National Cancer Institute 

CARCINOGENESIS 

Technical Report Series 

No. 20 

1977 

BIOASSAY OF 

DAPSONE 

FOR POSSIBLE CARCINOGENICITY 

CAS No. 80-08-0 

NCI-CG-TR-20 

U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE 

Public Health Service 

National Institutes of Health 

BIOASSAY OF
 

DAPSONE
 

FOR POSSIBLE CARCINOGENICITY
 

Carcinogen Bioassay and Program Resources Branch
 

Carcinogenesis Program
 

Division of Cancer Cause and Prevention
 

National Cancer Institute
 

National Institutes of Health
 

Bethesda, Maryland 20014
 

DHEW Publication No. (NIH) 77-820
 

BIOASSAY OF
 

DAPSONE
 

FOR POSSIBLE CARCINOGENICITY
 

Carcinogenesis Program
 

Division of Cancer Cause and Prevention
 

National Cancer Institute
 

National Institutes of Health
 

CONTRIBUTORS; This report presents the results of the bioassay
 

of dapsone for possible carcinogenicity, conducted for the
 

Carcinogen Bioassay and Program Resources Branch, Carcinogenesis
 

Program, Division of Cancer Cause and Prevention, National Cancer
 

Institute (NCI), Bethesda, Maryland. The bioassay was conducted
 

by Southern Research Institute, Birmingham, Alabama, initially
 

under direct contract to NCI and currently under a subcontract to
 

Tracor Jitco, Inc., prime contractor for the NCI carcinogenesis
 

bioassay program.
 

The experimental design and doses were determined by Drs. D. P.
 1 1 2
 Griswold , J. D. Prejean , E. K. Weisburger , and J. Η.
 

Weisburger2>3. ^s^ j # Belzer^ and Mr. I. Brown-' were responsible
 

for the care and feeding of the laboratory animals. Data
 

management and retrieval were performed by Ms. C. A. Dominick^-.
 

Histopathologic examinations were performed by Drs. S. D.
 

Kosankel and J. C. Peckham-*-, and the diagnoses included in this
 

report represent their interpretation. Pathologists at NCI and
 

Tracor Jitco have reviewed selected slides and concur with the
 

overall pathologic evaluation of the study.
 

Animal pathology tables and survival tables were compiled at EG&G
 

Mason Research Institute^. The statistical analyses were performed by Dr. J. R. Joiner-*, using methods selected for the
 

bioassay program by Dr. J. J. Gart^. Chemicals used in this
 

bioassay were analyzed under the direction of Dr. E. Murrill^,
 

and the analytical results were reviewed by Dr. C. W. Jameson^.
 

This report was prepared at Tracor Jitco under the direction of
 

NCI. Those responsible for the report at Tracor Jitco were Dr.
 

iii
 
Marshall Steinberg5

, Director of the Bioassay Program; Drs. J. F.
 

Robens5 and R. W. Fogleman5, toxicologists; Ms. L· A. Waitz5,
 

bioscience writer; and Dr· E. W. Gunberg5, technical editor,
 

assisted by Ms. Y. E. Presley5 and Ms. P. J. Graboske5.
 

The statistical analysis was reviewed by a member or members of
 

the Mathematical Statistics and Applied Mathematics Section of
 

NCI (Dr. John J. Gart, Mr. Jun-mo Nam, Dr. Hugh. M. Pettigrew,
 

and Dr. Robert E. Tarone served as reviewers on an alternating
 

basis).
 

The following other scientists at the National Cancer Institute
 

were responsible for evaluating the bioassay experiment,
 

interpreting the results, and reporting the findings:
 

Dr. Kenneth C. Chu
 

Dr. Cipriano Cueto, Jr.
 

Dr. J. Fielding Douglas
 

Dr. Dawn G. Goodman
 

Dr. Richard A. Griesemer
 

Dr. Thomas W. Orme
 

Dr. Robert A. Squire8
 

Dr. Jerrold M. Ward
 

^•Southern Research Institute, 2000 Ninth Avenue South,
 

Birmingham, Alabama.
 

^Carcinogenesis Program, Division of Cancer Cause and Prevention,
 

National Cancer Institute, National Institutes of Health,
 

Bethesda, Maryland.
 

^Now with the Naylor Dana Institute for Disease Prevention,
 

American Health Foundation, Hammond House Road, Valhalla,
 

New York.
 

^EG&G Mason Research Institute, 1530 East Jefferson Street,
 

Rockville, Maryland.
 

5Tracor Jitco, Inc., 1776 East Jefferson Street, Rockville,
 

Maryland.
 

iv
 
^Mathematical Statistics and Applied Mathematics Section,
 

Biometry Branch, Field Studies and Statistics, Division of
 

Cancer Cause and Prevention, National Cancer Institute, National
 

Institutes of Health, Bethesda, Maryland.
 

^Midwest Research Institute, 425 Volker Boulevard, Kansas City,
 

Missouri.
 

"Mow with the Division of Comparative Medicine, Johns Hopkins
 

University, School of Medicine, Traylor Building, Baltimore,
 

Maryland.
 

SUMMARY
 

A bioassay of dapsone, 4,4'-sulfonyldianiline, for possible
 

carcinogenicity was conducted by administering the test material
 

in Eeed to Fischer 344 rats and B6C3F1 mice.
 

Groups of 35 rats and 35 mice of each sex were administered
 

dapsone at one of two doses, either 600 or 1,200 ppm for rats and
 

either 500 or 1,000 ppm for mice. The rats and mice were treated
 

for 78 weeks; the rats were then observed for 26-28 weeks, the
 

mice for 28-30 weeks. Matched controls consisted of groups of 15
 

untreated rats and 14 untreated mice of each sex; pooled
 

controls, used for statistical evaluation, consisted of the
 

matched controls combined with 30 male and 30 female untreated
 

rats and 29 male and 29 female untreated mice from similarly
 

performed bioassays of two other test chemicals. All surviving
 

rats were killed at 104-106 weeks, all surviving mice at 106-108
 

weeks.
 

Treated rats and mice had lower mean body weights than the
 

corresponding controls; when treatment was discontinued at week
 

78, both species showed some increase in body weight. Survival
 

among rats was unaffected by treatment with dapsone; adequate
 

numbers of animals survived for meaningful statistical analyses
 

of the Incidences of tumors. Dapsone did not adversely affect
 

the survival of mice, as shown by the test for positive
 

dose-related trend. Suppurative bronchopneumonia was found in
 

some mice in all matched-control and treated groups. Sevetal
 

control males died early in the study, while survival of the
 

other groups of mice was not affected until week 75.
 

Among rats, mesenchymal tumors of the abdominal organs or
 

peritoneal tissues occurred in 13/35 low-dose males and 22/33
 

high-dose males. None occurred among control males or among
 

control or treated females. The most commonly occurring tumors
 

were fibroma, fibrosarcoma, or sarcoma, NOS (not otherwise
 

specified), of the spleen and the peritoneum. In male rats,
 

these mesenchymal tumors of the spleen occurred in a
 

statistically significant incidence in both treated groups
 

vii
 
(low-dose 6/34, Ρ = 0.006; high-dose 14/32, Ρ < 0.001) when
 

compared with pooled controls. In the peritoneum, the incidences
 

of these mesenchymal tumors were significant in both treated
 

groups (low-dose 5/35, Ρ = 0.014; high-dose 6/33, Ρ = 0.005) when
 

compared with the pooled controls. No tumors related to
 

treatment were found in female rats.
 

Among the mice, there were no tumors that could clearly be
 

related to treatment.
 

It is concluded that under the conditions of this bioassay,
 

dapsone was not carcinogenic for female Fischer 344 rats or
 

B6C3F1 mice of either sex. Dapsone was carcinogenic
 

(sarcomagenic) for male Fischer 344 rats, causing mesenchymal
 

tumors in the spleen and the peritoneum.
 

viii
 
TABLE OF CONTENTS
 

Page
 

I. Introduction 1
 

II. Materials and Methods 3
 

A. Chemical 3
 

. Dietary Preparation 3
 

C. Animals 4
 

D. Animal Maintenance 4
 

E. Subchronic Studies 7
 

F. Designs of Chronic Studies 8
 

G· Clinical and Pathologic Examinations 11
 

H· Data Recording and Statistical Analyses 12
 

III. Results - Rats 19
 

A. Body Weights and Clinical Signs (Rats) 19
 

B. Survival (Rats) 19
 

C. Pathology (Rats) 22
 

D. Statistical Analyses of Results (Rats) 26
 

IV. Results - Mice 31
 

A. Body Weights and Clinical Signs (Mice) 31
 

B. Survival (Mice) 31
 

C. Pathology (Mice) 34
 

D. Statistical Analyses of Results (Mice) 35
 

V. Discussion ; 39
 

VI. Bibliography 43
 

APPENDIXES
 

Appendix A Summary of the Incidence of Neoplasms in
 

Rats Fed Dapsone in the Diet 45
 

Table Al Summary of the Incidence of Neoplasms in
 

Male Rats Fed Dapsone in the Diet 47
 

Table A2 Summary of the Incidence of Neoplasms in
 

Female Rats Fed Dapsone in the Diet 50
 

ix
 
Page
 

Appendix Β Summary of the Incidence of Neoplasms in 

Mice Fed Dapsone in the Diet 53 

Table B1 Summary of the Incidence of Neoplasms in 

Male Mice Fed Dapsone in the Diet 55 

Table B2 Summary of the Incidence of Neoplasms in 

Female Mice Fed Dapsone in the Diet 58 

Appendix C Summary of the Incidence of Nonneoplastic 

Lesions in Rats Fed Dapsone in the Diet 61 

Table C1 Summary of the Incidence of Nonneoplastic 

Lesions in Male Rats Fed Dapsone 

in the Diet 63 

Table C2 Summary of the Incidence of Nonneoplastic 

Lesions in Female Rats Fed Dapsone 

in the Diet 66 

Appendix D Summary of the Incidence of Nonneoplastic 

Lesions in the Mice Fed Dapsone 

in the Diet 69 

Table D1 Summary of the Incidence of Nonneoplastic 

Lesions in the Male Mice Fed Dapsone 

in the Diet 71 

Table D2 Summary of the Incidence of Nonneoplastic 

Lesions in Female Mice Fed Dapsone 

in the Diet 74 

Appendix Ε Analyses of the Incidence of Primary Tumors 

in Rats Fed Dapsone in the Diet 77 

Table E1 Analyses of the Incidence of Primary Tumors 

in Male Rats Fed Dapsone in the Diet 79 

Table E2 Analyses of the Incidence of Primary Tumors 

in Female Rats Fed Dapsone in the Diet 88 

χ 
Page 

Appendix F Analyses of the Incidence of Primary Tumors 

in Mice Fed Dapsone in the Diet 91 

Table Fl Analyses of the Incidence of Primary Tumors 

in Male Mice Fed Dapsone in the Diet 93 

Table F2 Analyses of the Incidence of Primary Tumors 

in Female Mice Fed Dapsone in the Diet 96 

TABLES 

Table 1

Table 2

 Design of Dapsone Chronic Feeding 

Studies in Rats

 Design of Dapsone Chronic Feeding 

9 

Studies in Mice « 10 

FIGURES 

Figure 1

Figure 2

 Growth Curves for Rats Fed Dapsone 

in the Diet

 Survival Curves for Rats Fed Dapsone 

in the Diet

 20 

 21 

Figure 3 Growth Curves for Mice Fed Dapsone 

in the Diet 32 

Figure 4 Survival Curves for Mice Fed Dapsone 

in the Diet 33 

xi
 

I. INTRODUCTION
 

Dapsone (CAS 80-08-0; NCI C01718) is the parent chemical of the
 

sulfone drugs, and the major therapeutic agent in this group for
 

the treatment of leprosy (Weinstein, 1975). It is also
 

administered to treat dermatitis herpetiformis and malaria, and
 

is used in combination with radiotherapy in the treatment of
 

gynecologic neoplasms (Graham et al., 1968; Graham et al. , 1969;
 

Rollo, 1975). The mechanism of action of the sulfones is not
 

known, although some evidence suggests that they act similarly to
 

the sulfonamides, which inhibit bacterial utilization of
 

p-aminobenzoic acid (Weinstein, 1975). Dapsone is also sold for
 

use as an accelerator in epoxy resins (RSA Corp., 1977). Dapsone
 

was selected for screening by the carcinogenesis program in an
 

attempt to evaluate the carcinogenicity of certain drugs that are
 

used extensively and for prolonged periods in humans.
 

1 

II. MATERIALS AND METHODS
 

A. Chemical
 

Dapsone is the generic name for 4,4'-sulfonyldianiline. It was
 

obtained in a single batch (Lot No. 870-5) from the RSA
 

Corporation, Ardsley, New York. This lot, according to the RSA
 

Corporation, met USP grade specifications, indicating a purity of
 

> 99%. Nonaqueous titration of the amine functions performed at
 

the Midwest Research Institute indicated 100.0 + 0.4%. The
 

melting point was 177.5-179°C (literature: 178.5°C). Elemental
 

analyses (C, Η, Ν, S) were correct for C]^2^12^2^2^> *-he molecular
 

formula of 4,4'-sulfonyldianiline· Identity was confirmed by
 

nuclear magnetic resonance and infrared spectra, which were in
 

agreement with the structure and matched the spectra found in the
 

literature.
 

The chemical was stored at 5°C in plastic bottles enclosed in
 

sealed plastic bags.
 

B. Dietary Preparation
 

Test diets were formulated every 2 weeks using finely ground
 

Wayne® Lab Blox (Allied Mills, Inc., Chicago, 111.) to which was
 

added the required amount of dapsone for each dietary concentration· A given amount of the test chemical was first hand3
 
mixed with a small amount of feed. This mixture was then added
 

to a larger quantity of feed to give the desired concentration of
 

the chemical, and mixed mechanically in a twin-shell blender for
 

not less than 10 minutes to assure homogeneity of the mixture·
 

Formulated diets were stored in plastic bags at room temperature
 

until used·
 

C. Animals
 

Fischer 344 rats and B6C3F1 mice, used in the chronic studies,
 

were obtained through contracts of the Division of Cancer
 

Treatment, National Cancer Institute. The rats were obtained
 

from Charles River Breeding Laboratories, Inc., Wilmington,
 

Massachusetts, and the mice were obtained in mixed shipments
 

from A. R. Schmidt, Madison, Wisconsin, and from Charles River
 

Laboratories. On arrival at the laboratory, all animals were
 

quarantined for an acclimation period (rats for 5 days, mice for
 

4 days) and were then assigned to control and treated groups·
 

D. Animal Maintenance
 

All animals were housed in temperature- and humidity-controlled
 

rooms. The temperature range was 20-24°C and the relative
 

humidity was maintained at 40-60%. Room air was changed 15
 

times per hour and passed through both incoming and exhaust
 

fiberglass roughing filters. In addition to natural light,
 

4 
illumination was provided by fluorescent light for 9 hours per
 

day. Food and water were supplied daily and were available ad
 

libitum.
 

Rats were housed five per cage and mice seven per cage in solid-


bottom stainless steel cages (Hahn Roofing and Sheet Metal Co·,
 

Birmingham, Ala.). The bottoms of the rat cages were lined with
 

Iso-Dri(Rw) hardwood chips (Carworth, Edison, N. J.), and cage tops
 

were covered with disposable filter bonnets beginning at week 25;
 

mouse cages were provided with Sterolit® clay bedding (Englehard
 

Mineral and Chemical Co., New York, N. Y.) . Bedding was replaced
 

once per week; cages, water bottles, feeders, and racks were
 

sanitized once per week.
 

The rats and mice were housed in separate rooms. Control animals
 

were housed with respective treated animals. Animals treated
 

with dapsone were maintained in the same rooms as animals of the
 

same species being treated with the following chemicals:
 

RATS
 

Feed Studies
 

4-acetyl-N-((cyclohexylamino)carbonyl)benzenesulfonamide
 

(acetohexamide) (CAS 968-81-0)
 

anthranilic acid (CAS 118-92-3)
 

l-butyl-3-(p-tolylsulfonyl)urea (tolbutamide) (CAS 64-77-7)
 

4-chloro-N-((propylamino)carbonyl)benzenesulfonamide
 

(chlorpropamide) (CAS 94-20-2)
 

5-(4-chlorophenyl)-6-ethyl-2,4-pyrimidinediamine
 

(pyrimethamine) (CAS 58-14-0)
 

5 
2,6-diamino-3-(phenylazo)pyridine hydrochloride (CAS 136-40-3)
 

L-tryptophan (CAS 73-22-3)
 

N-9H-fluoren-2-ylacetamide (CAS 53-96-3)
 

N-(p-toluenesulfonyl)-N'-hexamethyleniminourea
 

(tolazamide) (CAS 1156-19-0)
 

1-phenethylbiguanide hydrochloride (phenformin) (CAS 114-86-3)
 

pyrazinecarboxamide (pyrazinamide) (CAS 98-96-4)
 

4,4'-thiodianiline (CAS 139-65-1)
 

ethionamide (CAS 536-33-4)
 

MICE
 

Feed Studies
 

4-acetyl-N-((cyclohexylamino)carbonyl)benzenesulfonamide
 

(acetohexamide) (CAS 968-81-0)
 

anthranilic acid (CAS 118-92-3)
 

l-butyl-3-(p-tolylsulfonyl)urea (tolbutamide) (CAS 64-77-7)
 

4-chloro-N-((propylamino)carbonyl)benzenesulfonamide
 

(chlorpropamide) (CAS 94-20-2)
 

5-(4-chlorophenyl)-6-ethyl-2,4-pyrimidinediamine
 

(pyrimethamine) (CAS 58-14-0)
 

2,6-diamino-3-(phenylazo)pyridine hydrochloride (CAS 136-40-3)
 

L-tryptophan (CAS 73-22-3)
 

N-9H-fluoren-2-ylacetamide (CAS 53-96-3)
 

N-(p-toluenesulfonyl)-N'-hexamethyleniminourea
 

(tolazamide) (CAS 1156-19-0)
 

1-phenethylbiguanide hydrochloride (phenformin) (CAS 114-86-3)
 

pyrazinecarboxamide (pyrazinamide) (CAS 98-96-4)
 

4,4'-thiodianiline (CAS 139-65-1)
 

ethionamide (CAS 536-33-4)
 

Gavage Studies
 

cholesterol (ρ-(bis(2-chloroethyl)amino)phenyl)acetate
 

(phenesterin) (CAS 3546-10-9)
 

estradiol bis((p-(bis(2-chloroethyl)amino)phenyl)acetate)
 

(estradiol mustard) (CAS 22966-79-6)
 

Intraperitoneal Injection Studies
 

4'-(9-acridinylamino)methansulfon-m-aniside monohydrochloride
 

(MAAM) (NSC 141549)
 

acronine (CAS 7008-42-6)
 

5-azacytidine (CAS 320-67-2)
 

beta-2'-deoxy-6-thioguanosine monohydrate (beta-TGDR)
 

(CAS 789-61-7)
 

6
 
1,4-butanediol dimethanesulfonate (busulfan) (CAS 55-98-1)
 

emetine dihydrochloride tetrahydrate (CAS 316-42-7)
 

3,3' -iminobis-1-propanol dimethanesulfonate (ester)
 

hydrochloride (CAS 3458-22-8)
 

(+)-4,4'-(1-methyl-l,2-ethanediyl)bis-2,6-piperazinedione
 

(ICRF-159) (CAS 21416-87-5)
 

N,3-bis(2-chloroethyl)tetrahydro-2H-l,3,2-oxazaphosphorin~2­

amine-2-oxide (isophosphamide) (CAS 3778-73-2)
 

N-(2-chloroethyl)-N-(l-methyl-2-phenoxyethyl)benzylamine
 

hydrochloride (phenoxybenzamine) (CAS 63-92-3)
 

N-(l-methylethyl)-4-((2-methylhydrazino)methyl)benzamide
 

monohydrochloride (procarbazine) (CAS 366-70-1)
 

tris(l-aziridinyl)phosphine sulfide (thio-TEPA) (CAS 52-24-4)
 

2,4,6»tris(dimethylamino)-s-triazine (CAS 645-05-6)
 

E. Subchronic Studies
 

Subchronic feeding studies were conducted to estimate the maximum
 

tolerated doses of dapsone, on the basis of which low and high
 

concentrations (hereinafter referred to as f!low doses11 and "high
 

doses") were determined for administration in the chronic
 

studies. In these subchronic studies, dapsone was added to the
 

animal feed in concentrations of 1,200, 3,000, 6,000, 15,000, or
 

30,000 ppm for rats and 2,000, 5,000, 10,000, or 50,000 ppm for
 

mice. The treated and control groups each consisted of five male
 

animals. The chemical was provided in the feed to the treated
 

groups 7 days per week for 45 days, followed by a 45-day period
 

of observation.
 

All rats receiving 30,000 ppm died before termination of the
 

study, as did 4/5 rats receiving 15,000 or 6,000 ppm, and 1/5
 

rats receiving 3,000 ppm. At 1,200 ppm there were no deaths;
 
weight gains in this group were depressed throughout both the
 

treatment and the observation periods, but were within 15% of the
 

control weights. The low and high doses for the chronic studies
 

in rats were set at 600 and 1,200 ppm·
 

Because deaths occurred in all treated groups of mice, a second
 

study was conducted using twofold increasing concentrations
 

ranging from 120 to 2,000 ppm. In this study, one animal
 

receiving 2^000 ppm died during week 2. Body weights of all
 

treated animals, and particularly those of the high-dose groups,
 

were depressed during the treatment period, but were similar to
 

those of the controls by the end of the observation period. The
 

low and high doses for the chronic studies in mice were set at
 

500 anc 1,000 ppm,
 

F. Designs of Chronic Studies
 

The designs of the chronic studies are shown in tables 1 and 2.
 

Since the numbers of animals in the matched-control groups were
 

small, pooled-control groups also were used for statistical
 

comparisons. Matched controls from the current studies on
 

dapsone were combined with matched conLrols from studies
 

performed on anthranilic acid (CAS 118-92-3) and 4,4'-thiodianiline (CAS 139-65-1). The pooled controls for statistical
 

tests using rats consisted «*f 45 males and 4-5 females; using
 

8
 
Table 1. Design of Dapsone Chronic Feeding Studies in Rats
 

Sex and Initial Dapsone Time on Study 

Treatment No. of in Diet Treated Untreated 

Group Animalsa (ppm)b (weeks) (weeks) 

Male 

Matched-Control 15 0 0 106 

Low-Dose 35 600 78 27 

High-Dose 35 1,200 78 26 

Female 

Matched-Control 15 0 0 106 

Low-Dose 35 600 78 27 

High-Dose 35 1,200 78 27 

aAll animals were 34 days of age when placed on study.
 

^Animals were fed diets containing dapsone 5 days per week, and
 

control diets 2 days per week.
 
Table 2. Design of Dapsone Chronic Feeding Studies in Mice
 

Sex and Initial Dapsone Time on Study 

Treatment No. of in Diet Treated Untreated 

Group Animalsa (ppm)b (weeks) (weeks) 

Male 

Matched-Control 14 0 0 106 

Low-Dose 35 500 78 29 

High-Dose 35 1,000 78 29 

Female 

Matched-Control 14 0 0 108 

Low-Dose 35 500 78 30 

High-Dose 35 1,000 78 29 

aMale animals were 34 days of age and females 38 days of age when
 

placed on study.
 

bAnimals were fed diets containing dapsone 5 days per week, and
 

control diets 2 days per week.
 

10
 
mice, 43 males and 43 females. The studies on chemicals other
 

than dapsone were also conducted at Southern Research Institute
 

and overlapped the dapsone study by at least 7 months for rats
 

and at least 10 months for mice. The matched-control groups for
 

the different test chemicals were of the same strain and from the
 

same supplier, and they were examined by the same pathologists.
 

G. Clinical and Pathologic Examinations
 

All animals were observed twice daily for signs of toxicity, and
 

palpated for masses at each weighing. Rats and mice were weighed
 

individually each week for 8 weeks and every 2 weeks for the
 

remainder of the study. Animals that were moribund at the time
 

of clinical examination were killed and necropsied.
 

The pathologic evaluation consisted of gross and microscopic
 

examination of major tissues, major organs, and all gross lesions
 

from killed animals and from animals found dead. The following
 

tissues were examined microscopically: skin, muscle, lungs and
 

bronchi, trachea, bone and bone marrow, spleen, lymph nodes,
 

thymus, heart, salivary gland, liver, gallbladder and bile duct
 

(mice), pancreas, esophagus, stomach, small intestine, large
 

intestine, kidney, urinary bladder, pituitary, adrenals thyroid,
 

parathyroid, mammary gland, prostate or uterus, testis or ovary,
 

brain and sensory organs. Peripheral blood smears were prepared
 

11
 
from each animal. Occasionally, additional tissues were also
 

examined microscopically. The different tissues were preserved
 

in 10% buffered formalin, embedded in paraffin, sectioned, and
 

stained with hematoxylin and eosin. Special staining techniques
 

were utilized when indicated for more definitive diagnosis.
 

A few tissues from some animals were not examined, particularly
 

from those animals that died early. Also, some animals were
 

missing, cannibalized, or judged to be in such an advanced state
 

of autolysis as to preclude histopathologic evaluation. Thus,
 

the number of animals from which particular organs or tissues
 

were examined microscopically varies, and does not necessarily
 

represent the number of animals that were placed on study in each
 

group.
 

H. Data Recording and Statistical Analyses
 

Pertinent data on this experiment have been recorded in an automatic data processing system, the Carcinogenesis Bioassay Data
 

System (Linhart et al. , 1974). The data elements include descriptive information on the chemicals, animals, experimental design,
 

clinical observations, survival, body weight, and individual
 

pathologic results, as recommended by the International Union
 

Against Cancer (Berenblum, 1969). Data tables were generated for
 

verification of data transcription and for statistical review.
 

12
 
These data were analyzed using the statistical techniques
 

described in this section. Those analyses of the experimental
 

results that bear on the possibility of carcinogenicity are
 

discussed in the statistical narrative sections.
 

Probabilities of survival were estimated by the product-limit
 

procedure of Kaplan and Meier (1958) and are presented in this
 

report in the form of graphs. Animals were statistically
 

censored as of the time that they died of other than natural
 

causes or were found to be missing; animals dying from natural
 

causes were not statistically censored. Statistical analyses for
 

a possible dose-related effect on survival used the method of Cox
 

(1972) for testing two groups for equality and Tarone's (1975)
 

extensions of Cox's methods for testing for a dose-related trend·
 

One-tailed Ρ values have been reported for all tests except the
 

departure from linearity test, which is only reported when its
 

two-tailed Ρ value is less than 0.05.
 

The incidence of neoplastic or nonneoplastic lesions has been
 

given as the ratio of the number of animals bearing such lesions
 

at a specific anatomic site (numerator) to the number of animals
 

in which that site is examined (denominator). In most instances,
 

the denominators included only those animals for which that site
 

was examined histologically. However, when macroscopic examination was required to detect lesions prior to histologic sampling
 

13
 
(e.g., skin or mammary tumors), or when lesions could have
 

appeared at multiple sites (e.g., lymphomas), the denominators
 

consist of the numbers of animals necropsied.
 

The purpose of the statistical analyses of tumor incidence is to
 

determine whether animals receiving the test chemical developed a
 

significantly higher proportion of tumors than did the control
 

animals. As a part of these analyses, the one-tailed Fisher
 

exact test (Cox, 1970) was used to compare the tumor incidence of
 

a control group with that of a group of treated animals at each
 

dose level. When results for a number of treated groups (k) are
 

compared simultaneously with those for a control group, a
 

correction to ensure an overall significance level of 0.05 may be
 

made. The Bonferroni inequality (Miller, 1966) requires that the
 

 value for any comparison be less than or equal to 0.05/k. In
 

cases where this correction was used, it is discussed in the
 

narrative section. It is not, however, presented in the tables,
 

where the Fisher exact Ρ values are shown.
 

The Cochran-Armitage test for linear trend in proportions, with
 

continuity correction (Armitage, 1971), was also used. Under the
 

assumption of a linear trend, this test determines if the slope
 

of the dose-response curve is different from zero at the one-


tailed 0.05 level of significance. Unless otherwise noted, the
 

direction of the significant trend is a positive dose relation14
 
ship. This method also provides a two-tailed test of departure
 

from linear trend.
 

A time-adjusted analysis was applied when numerous early deaths
 

resulted from causes that were not associated with the formation
 

of tumors. In this analysis, deaths that occurred before the
 

first tumor was observed were excluded by basing the statistical
 

tests on animals that survived at least 52 weeks, unless a tumor
 

was found at the anatomic site of interest before week 52. When
 

such an early tumor was found, comparisons were based exclusively
 

on animals that survived at least as long as the animal in which
 

the first tumor was found. Once this reduced set of data was
 

obtained, the standard procedures for analyses of the incidence
 

of tumors (Fisher exact tests, Cochran-Armitage tests, etc.) were
 

followed.
 

When appropriate, life-table methods were used to analyze the
 

incidence of tumors. Curves of the proportions surviving without
 

an observed tumor were computed as in Saffiotti et al. (1972).
 

The week during which animals died naturally or were sacrificed
 

was entered as the time point of tumor observation. Cox's
 

methods of comparing these curves were used for two groups;
 

Tarone's extension to testing for linear trend was used for three
 

groups. The statistical tests for the incidence of tumors which
 

used life-table methods were one-tailed and, unless otherwise
 

15
 
noted, in the direction of a positive dose relationship. Significant departures from linearity (P < 0.05, two-tailed test) were
 

also noted.
 

The approximate 95 percent confidence interval for the relative
 

risk of each treated group compared to its control was calculated
 

from the exact interval on the odds ratio (Gart, 1971). The
 

e r e s
 relative risk is defined as P^/Pc w ^ Pt *- the true binomial
 

probability of the incidence of a specific type of tumor in a
 

treated group of animals and pc is the true probability of the
 

spontaneous incidence of the same type of tumor in a control
 

group. The hypothesis of equality between the true proportion of
 

a specific tumor in a treated group and the proportion in a
 

control group corresponds to a relative risk of unity. Values in
 

excess of unity represent the condition of a larger proportion in
 

the treated group than in the control.
 

The lower and upper limits of the confidence interval of the
 

relative risk have been included in the tables of statistical
 

analyses. The interpretation of the limits is that in
 

approximately 95% of a large number of identical experiments, the
 

true ratio of the risk in a treated group of animals to that in a
 

control group would be within the interval calculated from the
 

experiment. When the lower limit of the confidence interval is
 

greater than one, it can be inferred that a statistically
 

16
 
significant result (a P < 0*025 one-tailed test when the control
 

incidence is not zero, Ρ < 0·050 when the control incidence is
 

zero) has occurred· When the lower limit is less than unity, but
 

the upper limit is greater than unity, the lower limit indicates
 

the absence of a significant result while the upper limit
 

indicates that there is a theoretical possibility of the
 

induction of tumors by the test chemical, which could not be
 

detected under the conditions of this test·
 

17
 

III. RESULTS - RATS
 

A. Body Weights and Clinical Signs (Rats)
 

Among males, decreased body weight gains occurred in the high-


dose animals after about 20 weeks on study; animals at the low
 

dose also had depressed body weights as compared with the matched
 

controls after approximately 40 weeks· Body weights in both
 

high- and low-dose female rats were lower than those in the
 

control group after aproximately 12 weeks· Following withdrawal
 

of the chemical at week 78, the body weights of these groups
 

increased (figure 1)·
 

B. Survival (Rats)
 

Kaplan and Meier curves estimating the probabilities of survival
 

for male and female rats fed dapsone in the diet at the doses of
 

this experiment, together with those of the controls, are shown
 

in figure 2· In both sexes, the Tarone test results are not
 

significant at the 0.05 level for positive dose-related trend in
 

mortality over the period. In male rats, 51% of both treated
 

groups and 73% of the controls lived to the end of the study·
 

The overall survival rate was higher in females than in males,
 

with more than 80% of the treated and control female rats living
 

to termination of the study. Sufficient animals of both sexes
 

19
 
450 

400 

s 

X 

350

300­

D 

_,DD o ° O, 

UJ 

δ 

> 

s 

250 

200 

< 

LU 150­

100­

8 

MALE RATS 

D MATCHED CONTROL 

 LOW DOSE 

 HIGH DOSE 

50 ­

300 

20 40 60

TIME ON STUDY (WEEKS) 

 80 100 120 

D 

250 

2

Ι 

Ο 

Ω 

Ο 

GO 

< 

LU 

Έ 

 200 Η 

150

100 ­

A 

,Ο*Δ ΔΔ^ 

D DOG 

FEMALE RATS 

D MATCHED CONTROL 

 LOW DOSE 

50 s HIGH DOSE 

20 40 60 80 

TIME ON STUDY (WEEKS) 

Figure 1. Growth Curves for Rats Fed Dapsone in the Diet 

100 120 

2 0 
0 60 

< 04°H m 

Ο 

QC 

a. 0 30 

D

MALE RATS 

 MATCHED CONTROL 

 LOW DOSE 

 HIGH DOSE 

30 45 60 75 90 

TIME ON STUDY (WEEKS) 

105 120 

0 90 ­

λ ""Ι

 ; (ID 

0 80 ­

J

> 

070 

* 0 60 ­

0 ) 

LL 

o 

> 0 50 ­ BIL < 0 40 ­

OQ 

Ο 

QC 

°" 0 30 ­ FEMALE RATS 

D MATCHED CONTROL 

 LOW DOSE
 

 HIGH DOSE
 

0 20 ­

0 10 ­

105 120 

TIME ON STUDY (WEEKS) 

Figure 2. Survival Curves for Rats Fed Dapsone in the Diet 

21
 
were available for meaningful statistical analyses of the
 

incidences of late-developing tumors.
 

C. Pathology (Rats)
 

Histopathologic findings on neoplasms in rats are summarized in
 

Appendix A, tables Al and A2; findings on nonneoplastic lesions
 

are summarized in Appendix C, tables CI and C2.
 

A variety of neoplasms occurred in both the control and treated
 

groups. With the exception of malignant lymphomas and
 

mesenchymal tumors of the abdominal cavity and viscera in treated
 

male rats, the neoplasms listed in Appendix A either occurred
 

with approximately equal frequency in treated and matched-control
 

rats, or occurred in insufficient numbers for accurate evaluation
 

of dose relationships.
 

Of the low-dose male rats, 4/35 (11%) had lesions classified as
 

malignant lymphomas of the histiocytic type. Similar lymphoreticular neoplasms have been observed previously in the Fischer
 

344 rat independent of any treatment. In some areas, the histiocytes of the lymphomas had marked pleomorphism including spindle-


cell shapes with various degrees of invasion into adjacent
 

tissues and the peritoneal cavity. In these areas, the malignant
 

histiocytes could not be differentiated from spindle cells of
 

mesenchymal tumors arising from the spleen and peritoneum.
 

22
 
Mesenchymal lesions which occurred only in chemical-treated male
 

rats had the following tissue distribution and incidences:
 

Tissue-Lesion
 

Spleen
 

sarcoma, NOS
 

fibroma
 

fibrosarcoma
 

fibrosis
 

metaplasia, osseous
 

Pancreas
 

fibroma
 

metaplasia, osseous
 

Abdominal cavity
 

fibroma
 

Peritoneum
 

sarcoma, NOS
 

fibroma
 

fibrosarcoma
 

fibrosis
 

metaplasia, osseous
 

Peritoneal cavity
 

metaplasia, osseous
 

Mesentery
 

metaplasia, osseous
 

Multiple organs
 

sarcoma, NOS
 

fibrosarcoma
 

metaplasia, osseous
 

Number of Rats Examined
 

Not otherwise specified.
 

Matched
 

Control
 

JA
 

JA
 

JA
 

JA
 

JA
 

JA
 

JA
 

14
 

Low
 

Dose
 

Ih.
 

6 (18%)
 

3 (9%)
 

33
 

1 (3%)
 

35
 

1 (3%)
 

35
 

4 (11%)
 

1 (3%)
 

1 (3%)
 

2 (6%)
 

2 (6%)
 

35
 

1 (3%)
 

35
 

1 (3%)
 

_35
 

1 (3%)
 

35
 

High
 

Dose
 

32
 

3 (9%)
 

10 (31%)
 

3 (9%)
 

3 (9%)
 

6 (19%)
 

32
 

1 (3%)
 

11
 

33
 

3 (9%)
 

3 (9%)
 

1 (3%)
 

11
 

11
 

33
 

1 (3%)
 

1 (3%)
 

33
 

23
 
The group frequencies for animals with lesions of the abdominal
 

organs or peritoneal tissues were as follows: mesenchymal
 

tumors, low-dose males 13/35 (37%) and high-dose males 22/33
 

(67%); splenic and peritoneal fibrosis, low-dose males 4/35 (11%)
 

and high-dose males 3/33 (9%); and osseous metaplasia, low-dose
 

males 3/35 (9%) and high-dose males 7/33 (21%).
 

The mesenchymal tumors were classified as fibromas, fibrosarcomas, and sarcomas, NOS· They were spindle-cell neoplasms
 

which varied in morphology and differentiation and had various
 

degrees of collagen formation. The fibromas had well-differentiated fibroblasts with ample collagen, whereas the fibrosarcomas
 

were more pleomorphic, more anaplastic, and more variable in the
 

amount of collagen deposited. The poorly differentiated
 

spindle-cell tumors with little or no collagen production were
 

classified as sarcomas, NOS. Nonneoplastic proliferation of the
 

connective tissues, either fibrosis or fibroplasia, showed mature
 

collagen formation. Osseous metaplasia was associated with
 

proliferation of connective tissues, and was most often seen in
 

rats with neoplastic lesions. These osseous lesions were
 

well-differentiated, localized, and noninvasive. They did not
 

metastasize.
 

In addition to the neoplastic and nonneoplastic proliferative
 

lesions of the connective tissues of the abdomen, a number of
 

24
 
other degenerative, proliferative, and inflammatory changes were
 

also encountered in animals of the treated and control groups.
 

These nonneoplastic lesions are commonly seen in aged rats.
 

The spleen appeared to be a primary site affected by dapsone.
 

Both neoplastic and nonneoplastic proliferative lesions were
 

often present in the same spleen* These proliferative
 

mesenchymal lesions ranged from focal areas of fibrosis,
 

fibroplasia, and fibromas with deposits of mature collagen to
 

poorly differentiated fibrosarcomas and sarcomas of unspecified
 

type. In some rats, lesions became disseminated throughout the
 

peritoneal cavity. The formation of well-differentiated
 

membranous bone and osseous metaplasia are believed to be
 

secondary to the neoplastic proliferation of the connective
 

tissues caused by chemical treatment.
 

In the judgment of the pathologists, a dose-related increase
 

occurred in the number and malignancy of abdominal tumors found
 

in male Fischer 344 rats. Under the conditions of this study,
 

dapsone was carcinogenic (sarcomagenic) for male but not female
 

Fischer 344 rats.
 

D. Statistical Analyses of Results (Rats)
 

Tables El and E2 in Appendix Ε contain the statistical analyses
 

of the incidences of those specific primary tumors that were
 

25
 
observed in at least 5% of one or more treated groups of either
 

sex.
 

In male rats, the Cochran-Armitage test results for positive
 

dose-related trend in proportions of fibroma of the spleen are
 

significant when the pooled-control group (P < 0·001) or the
 

matched-control group (P = 0.012) is used. The Fisher exact test
 

shows that the incidence in the high-dose group is significantly
 

higher than that in either the pooled controls (P < 0.001) or the
 

matched controls (P = 0.016), and the incidence in the low-dose
 

group is significantly higher than that in the pooled controls
 

(P = 0.006). The lower limits of the 95% confidence interval of
 

these relative risks have values greater than one. The
 

statistical conclusion is that the occurrence of fibroma of the
 

spleen in male rats is associated with dapsone at the doses of
 

this experiment. No such tumor was observed in female rats.
 

Fibrosarcomas of the spleen were found exclusively in the high-


dose males. The Cochran-Armitage test shows probability levels
 

of 0.023 when the pooled controls are used. The Fisher exact
 

test results are not significant. The spontaneous rate of this
 

tumor in the male Fischer 344 historical-control rats compiled to
 

date by this laboratory is 0/235. No such tumor was observed in
 

female rats.
 

26
 
The analyses of the incidence of sarcoma, NOS, of the spleen in
 

male rats show significant Cochran-Armitage test results (P =
 

0.023) when the pooled-control group is used. The Fisher exact
 

test results are not significant. The incidence observed in the
 

male historical-control rats compiled to date by this laboratory
 

is 0/235. No such tumor was observed in females. When the
 

incidences of fibroma, fibrosarcoma, and sarcoma, NOS, of the
 

spleen in male rats are grouped for statistical analyses, all
 

test results are significant (P j< 0.006), indicating a dose
 

association of this combination of tumors with the chemical.
 

Malignant lymphomas were observed exclusively in the low-dose
 

male rats. The Cochran-Armitage test results for linearity are
 

not significant, but an indicated departure from linear trend is
 

observed when the pooled-control group (P = 0.003) or the
 

matched-control group (P = 0.022) is used, since the proportion
 

in the low-dose group is greater than that in the high-dose
 

group. The Fisher exact test results show a P value of 0.035
 

when the incidence in the low-dose group is compared with that in
 

the pooled-control group, but this is above the 0.025 level
 

required by the Bonferroni inequality criterion for significance.
 

No such tumors were observed in female rats.
 

In male rats, the Cochran-Armitage tests on the proportions of
 

sarcoma, NOS, of the peritoneum are not significant. The Fisher
 

27
 
exact test shows a Ρ value of 0.035 when the incidence in the
 

low-dose group is compared with that in the pooled-control group,
 

and the lower limit of the 95% confidence interval for the
 

relative risk of the low-dose group versus the pooled-control
 

group has a value greater than one. This positive finding is
 

accentuated by the zero incidence of this tumor in the 235
 

Fischer 344 male historical-control rats from similar bioassays
 

conducted by this laboratory. However, the probability level of
 

0.035 is above the Bonferroni criterion of 0.025, and therefore,
 

the significance of the result of the analysis of this specific
 

tumor is questionable. No such tumors were observed in female
 

rats.
 

Fibrosarcomas of the peritoneum of male rats were observed in
 

both treated groups, and the incidence in the high-dose group was
 

three times that in the low-dose group. The Cochran-Armitage
 

test shows a probability level of 0.037 when the pooled-control
 

group is used, but the Fisher exact test shows that the
 

incidences in the treated groups are not significantly higher
 

than the incidence in either of the control groups. This tumor
 

did not occur in any of the 235 Fischer 344 male historical-


control rats used by this laboratory. When the incidences of
 

fibrosarcoma or of sarcoma, NOS, of the peritoneum in male rats
 

are grouped for statistical analysis, increased significance (P ^<
 

28
 
0.014) is observed for both Fisher exact test results and for the
 

test of linear trend using the pooled controls. The statistical
 

conclusion is that the combination of these tumors and the
 

chemical are dose related.
 

Negative results are observed in the incidence of mammary tumors
 

in female rats, where the incidence in the pooled controls
 

exceeds the incidences in the treated groups. There is no other
 

incidence of tumors at any specific site in either male or female
 

rats for which the statistical test results are significant in
 

the positive direction.
 

29
 

IV. RESULTS - MICE
 

A. Body Weights and Clinical Signs (Mice)
 

Mean body weights of both high- and low-dose male mice were lower
 

than those of the matched controls from initiation of the study
 

to about week 70 (figure 3). Among the females, the mean body
 

weights of the matched controls were unusually high, approaching
 

50g, and it is difficult to assess the significance of the lower
 

mean body weights among the treated animals.
 

When treatment was stopped at week 78, body weights increased.
 

At this time, mean body weights of the controls decreased to less
 

than those of the male treated groups, and were equal to those of
 

the female treated groups.
 

B. Survival (Mice)
 

Kaplan and Meier curves estimating the probabilities of survival
 

for male and female mice fed dapsone in the diet at the doses of
 

this experiment, together with those of the controls, are shown
 

in figure 4. In both sexes, the Tarone test results for positive
 

dose-related trend in mortality over the period are not significant. In male mice, 73% of the high-dose mice and 67% of the
 

low-dose mice, but only 8% of the controls, survived to the end
 

of the study. Early deaths in the male controls were not tumor
 

31
 
MALE MICE 

D MATCHED CONTROL 

 LOW DOSE 

 HIGH DOSE 

40 50 60 70 80 90 100 110 

TIME ON STUDY (WEEKS) 

FEMALE MICE 

D MATCHED CONTROL 

 LOW DOSE 

 HIGH DOSE 

TIME ON STUDY (WEEKS) 

Figure 3, Growth Curves for Mice Fed Dapsone in the Diet 

32 
 ο a 

', Δ 

Δ 

o - 0--, 

Δ 

(SO 

DC 

D 

CO 

LL 

Ο 

>• 

<

0Q 

Ο 

QC 

0­

 40 

 30 

MALE MICE 

 MATCHED CONTROL 

 LOW DOSE 

 HIGH DOSE 

45 60 75 90 

TIME ON STUDY (WEEKS) 

1 ο Β 

D 

CO 

m 

<

CD 

ο 

QCft 

 0 40 

0 30 FEMALE MICE 

D MATCHED CONTROL 

 LOW DOSE 

 HIGH DOSE 

Figure 4.

45 60 75 90 

TIME ON STUDY (WEEKS) 

 Survival Curves for Mice Fed Dapsone in the Diet 

13b 

33 
associated, since there was no incidence of tumors in this group.
 

The median time on study was 69 weeks in the controls. Fewer
 

females than males survived, with only 23% of the high-dose
 

group, 31% of the low-dose group, and 43% of the controls living
 

to termination of the study. The median time on study was 92
 

weeks in the treated groups and 102 weeks in the controls. The
 

severe early mortality rate in the female mice may have
 

suppressed the incidence of late-developing tumors.
 

C. Pathology (Mice)
 

Histopathologic findings on neoplasms in mice are summarized in
 

Appendix B, tables Bl and B2; findings on nonneoplastic lesions
 

are summarized in Appendix D, tables Dl and D2.
 

A variety of neoplasms occurred in both matched-control and
 

treated groups. The neoplasms listed in Appendix Β occurred with
 

approximately equal frequency in treated and control mice, or
 

appeared in insignificant numbers. No malignant tumors occurred
 

in male mice of this study, and more neoplasms occurred in
 

control females than in treated females. No tumor metastases
 

were recorded in these mice.
 

In addition to the neoplastic lesions, a number of degenerative,
 

proliferative, and inflammatory changes were encountered in
 

34
 
animals of both the treated and control groups (Appendix D) .
 

These nonneoplastic lesions are commonly seen in aged mice;
 

however, the suppurative lesions involving the lungs were
 

associated with increased mortalities or decreased life spans in
 

the treated and control groups of mice. The incidence of
 

suppurative bronchopneumonia in the male mice was as follows:
 

matched controls 6/11 (55%), low-dose group 5/33 (15%), and
 

high-dose group 9/32 (29%). In the female mice the incidence was
 

as follows: matched controls 9/13 (69%), low-dose group 22/30
 

(73%), and high-dose group 21/35 (60%). The reduction in life
 

spans was caused by respiratory disease.
 

In the judgment of the pathologists, feeding the mice dapsone in
 

the diet for 18 months resulted in no increase in the incidence
 

of tumors. Under the conditions of this study, dapsone was not
 

carcinogenic for B6C3F1 mice.
 

D. Statistical Analyses of Results (Mice)
 

Tables Fl and F2 in Appendix F contain the statistical analyses
 

of the incidences of those specific primary tumors that were
 

observed in at least 5% of one or more treated groups of either
 

sex.
 

In male mice, although the results of the Cochran-Armitage test
 

35
 
for positive dose-related linear trend in the incidence of
 

alveolar/bronchiolar adenoma of the lung are not significant, the
 

Fisher exact test shows a Ρ value of 0.031 when the incidence in
 

the low-dose group is compared with that in the pooled-control
 

group. This probability level, however, is below the Bonferroni
 

criterion of 0.025 required by the multiple comparisons.
 

Therefore, association between this incidence of tumors and
 

dapsone is not confirmed, since the incidence in the high-dose
 

group is not statistically significant. No such tumor was
 

observed in female mice.
 

There is no other incidence of tumors at any specific site in
 

either male or female mice for which the statistical test results
 

are significant in the positive direction. When lymphoma and
 

leukemia in female mice were combined for analysis, the incidence
 

of leukemia was not included in table F2, since the proportion in
 

each of the treated groups is less than 5%. A list of the
 

incidences of each type of tumor is provided in Appendix B,
 

tables Bl and B2.
 

In all but one of the 95% confidence intervals, shown in the
 

tables, the lower limit has a value less than one; this indicates
 

the negative aspects of the results. It should also be noted
 

that each of these intervals has an upper limit greater than one,
 

36
 
indicating the theoretical possibility of the induction of tumors
 

by dapsone, which could not be detected under the conditions of
 

this test.
 

37
 

V. DISCUSSION
 

In this bioassay, dapsone was toxic to both the treated rats and
 

treated mice, since the mean body weights of these animals were
 

lower than those of the corresponding matched controls throughout
 

most of the study. However, the body weights of control female
 

mice were unusually high. When the drug was discontinued at week
 

78, treated animals of both species showed varying increases in
 

body weight.
 

Dapsone did not affect survival of rats; adequate numbers of
 

animals survived for meaningful statistical analyses of the
 

incidences of tumors. Dapsone also did not affect the survival
 

of mice, as shown by the test for positive dose-related trend,
 

but suppurative bronchopneumonia was found in some animals in all
 

matched-control and treated groups. Several control males died
 

early in the study, while survival of the other groups of mice
 

was not affected until week 75.
 

Among rats, mesenchymal tumors of the abdominal organs or
 

peritoneal tissues occurred in 13/35 low-dose males and 22/33
 

high-dose males. None occurred among control males or among
 

control or treated females* The most commonly occurring tumors
 

were fibroma, fibrosarcoma, or sarcoma, NOS, of the spleen and
 

the peritoneum. In male rats, these mesenchymal tumors of the
 

39
 
spleen occurred in a statistically significant incidence in both
 

treated groups (low-dose 6/34, Ρ = 0.006; high-dose 14/32, Ρ <
 

0.001) when compared with pooled controls. In the peritoneum,
 

the incidences of these mesenchymal tumors were significant in
 

both treated groups (low-dose 5/35, Ρ = 0.014; high-dose 6/33,
 

 = 0.005) when compared with the pooled controls. No tumors
 

related to treatment were found in female rats.
 

Among the mice, there were no tumors that could clearly be
 

related to treatment. In the males, alveolar/bronchiolar adenoma
 

was observed in 5/33 low-dose animals. Although significant (P =
 

0.031) when compared with pooled controls, the tumors cannot
 

clearly be associated with treatment, because of the low
 

incidence in the low-dose group, and because only one tumor was
 

found in the high-dose group» Similar tumors were not observed
 

in female mice.
 

In studies of the toxicity of dapsone in animals, Dhar and
 

Mukherji (1971) administered daily intraperitoneal injections at
 

a dose of 20 mg/kg/week (chosen to simulate the human dose) for
 

22 weeks. In this study, there were minor changes in
 

hematological values, but none in the histology of the liver or
 

spleen. Higher doses for shorter periods of time caused anemia
 

and enlargement and degeneration of the spleen and liver.
 

40
 
Bergel (1973) reported that in a feeding study with Wistar rats,
 

tumors were found in 8/15 animals living more than 17 months, but
 

none were found in the 15 controls. Five of the eight animals
 

had tumors similar to those found in significant incidences in
 

rats in the present bioassay; i.e., mesenchymal tumors of the
 

peritoneum and organs of the abdominal cavity.
 

Dapsone inhibits the oxidation of pyruvate in the citric acid
 

cycle in rats and mice, and this is believed to be related to the
 

toxicity of the chemical (Wu and Dubois, 1970). It is
 

metabolized to the monohydroxylamine by N-oxidation; this occurs
 

to a greater extent in man than in rats (Israili et al. , 1973).
 

The monohydroxylamine metabolite is excreted in the urine in the
 

form of various conjugates.
 

It is concluded that under the conditions of this bioassay,
 

dapsone was not carcinogenic for female Fischer 344 rats or
 

B6C3F1 mice of either sex. Dapsone was carcinogenic
 

(sarcomagenic) for male Fischer 344 rats, causing mesenchymal
 

tumors in the spleen and the peritoneum.
 

41
 

VI. BIBLIOGRAPHY
 

Armitage, Ρ·, Statistical Methods in Medical Research, John Wiley
 

& Sons, Inc., New York, 1971, pp. 362-365.
 

Berenblum, I., ed., Carcinogenicity Testing: A Report of the
 

Panel of Carcinogenicity of the Cancer Research Commission
 

-2JL the UICC, Vol. _2, International Union Against Cancer,
 

Geneva, 1969.
 

Cox, D. R. , Regression models and life tables. J^_ IU_ Statist.
 

S£c^_ t 3A: 187-220, 1972.
 

Cox, D. R. , Analysis of Binary Data, Methuen & Co., Ltd., London,
 

1970, pp. 48-52.
 

Dtiar, D. C. and Mukherji, Α., Effect of long-term administration
 

of 4,4'-diamino diphenyl sulphone (DDS) in white rats.
 

Indian J. Exp. Biol. 9:388-390, 1971.
 

Gart, J. J., The comparison of proportions: a review of
 

significance tests, confidence limits and adjustments for
 

stratification. Rev. Int. Stat. Inst. 39^148-169, 1971.
 

Graham, J. and Graham, R. , Cancer treatment with sulfones. Surg.
 

Gynec. Obstet. 127:103-107, 1969.
 

Graham, J., Graham, R. , and Hirabayashi, K. , Recurrent cancer of
 

the cervix uteri. Surg. Gynec. Obstet. 126:799-804, 1968.
 

Israili, Z. H. , Cucinell, S. Α., Vaught, J., Davis, Ε. , Lesser,
 

J. Μ. , and Dayton, P. G., Studies of the metabolism of
 

dapsone in man and experimental animals: formation of
 

N-hydroxy metabolites. J_^ Pharmacol. Expertl. Therap. 187
 

(1):138-151, 1973.
 

Kaplan, E. L. and Meier, P., Nonparametric estimation from
 

incomplete observations. J^ Amer. Statist. Assoc. 53:
 

457-481, 1958.
 

Linhart, M. S. , Cooper, J. Α., Martin, R. L. , Page, N. P., and
 

Peters, J. Α., Carcinogenesis bioassay data system, Comp.
 

and Biomed. Res. 7:230-248, 1974.
 

43
 
Miller, R· G. , Jr. , Simultaneous Statistical Inference,
 

McGraw-Hill Book Co., New York, 1966, pp. 6-10.
 

Rollo, I· M., Drugs used in the chemotherapy of malaria, chapter
 

52 in Goodman, L. S. and Gilman, Α., eds., The
 

Pharmacological Basis of Therapeutics, Macmillan Publishing
 

Co., Inc., New York, 1975, pp. 1045-1069.
 

RSA Corporation, personal communication, Ardsley, Ν. Υ., 1977.
 

Saffiotti, U., Montesano5 R. , Sellakumar, A. R., Cefis, F., and
 

Kaufman, D. G. , Respiratory tract carcinogenesis in hamsters
 

induced by different numbers of administrations of benzo (a)
 

pyrene and ferric oxide. Cancer Res. 32:1073-1081, 1972.
 

Tarone, R. E., Tests for trend in life table analysis.
 

Biometrika 62:679-682, 1975.
 

Weinstein, L. , antimicrobial agents, drugs used in the 

chemotherapy of tuberculosis and leprosy, chapter 60 in 

Goodman, L. S. and Gilman, A. eds., The Pharmacological 

Basis of Therapeutics, Macmillan Publishing Co., Inc., New
 

York, 1975, pp. 1201-1223.
 

Wu, D· L. and Dubois, Κ. P. , Effect of DDS on endogenous
 

respiration and the oxidation of several substrates by rat
 

diaphragm. Arch, int. Pharmacodyn. 183:36-45, 1970.
 

44
 
APPENDIX A
 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN
 

RATS FED DAPSONE IN THE DIET
 

45
 

TABLE A1.

 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN MALE RATS 

FED DAPSONE INTHEDIET 

HIGH DOSE
 

35
 

33
 

33
 

(33)
 

1 (3%)
 

(31)
 

(33)
 

(32)
 

3 (9%)
 

10	 (31%)
 

3 (9%)
 

(32)
 

1 (3%)
 

(32)
 

ANIMALS INITIALLY IN STUDY
 

ANIMALS NECROPSIED
 

ANIMALS EXAMINED HISTOPATHOLOGICALLY
 

INTEGUHENTABY SYS1EB
 

*SUBCUT TISSUE
 

BASAL-CELL CARCINOMA
 

EESPIRATCBY SYSTEM
 

#LUNG


ALVEOLAR/BRONCHIOLAR CARCINOMA
 

OSTEOSARCOMA, METASTATIC


HEMATOPOIETIC SYSTEM
 

•MULTIPLE	 ORGANS
 

MALIG.LYMPHOMA, HISTIOCYTIC TYPE
 

UNDIFFERENTIATED LEUKEMIA
 

#SPLEEN
 

SARCOMA, NOS
 

FIBBCMA
 

FIBEOSARCCMA 

CIRCULATORY SYSTEM
 

NONE
 

DIGESTIVE SYSTEM
 

#LIVER
 

HEMANGIOSAfiCOMA
 

#PANCREAS
 

CONTROL LOU DOSE
 

15 35
 

35
 

14 35
 

(14) (35)
 

 (14) (34)
 

1 (3%)
 

 1 (7%)
 

(35)
 

4 (11%)
 

1 (756)
 

(14) (34) 

6 (18%)
 

(14) (35)
 

(14) (33)
 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

47 
TABLE A1. MALE RATS: NEOPLASMS (CONTINUED)

 

CONTROL LOW DOSE HIGH DOSE
 

URINARY SYSTEM 

NONE 

ENDOCRINE SYSTEM 

#PITUITARY 

CHROMOPHOBE

CHROMOPHOBE

 ADENOMA 

 CARCINOMA 

(14) 

1 (7%) 

(28) 

2 (7%) 

(28) 

2 (7%) 

2 (7%) 

iTHYROID 

FOLIICULAR-CELL CARCINOMA 

C-CELL ADENOMA 

C-CELL CARCINOMA 

#PANCREATIC ISLETS 

ISLET-CELL ADENOMA 

(14) 

1 (7%) 

(14) 

(33) 

1 (3%) 

1 (3%) 

1 0%) 

(33) 

1 (3%) 

(28) 

1 (4%) 

(32) 

REPRODUCTIVE SYSTEM 

#TESTIS

INTERSTITIAL-CELL TUMOR

 (14)

 14 (100%)

 (35)

 29 (83%)

 (31) 

 28 (90%) 

NERVOUS SYSTEM 

#BRAIN

SARCOMA, NOS

 (14)

 2 (14%) 

 (32) (32) 

SPECIAL SENSE ORGANS 

NONE 

MUSCULOSKELETAL SYSTEM 

NONE 

BODY CAVITIES 

• ABDOMINAL CAVITY

FIBBCMA 

 (14) (35) (33) 

i NUMBER OF ANIMALS WITH TISSUE EXAMINED

* NUMBER OF ANIMALS NECROFSIED 

 MICROSCOPICALLY 

48
 
TABLE A1. MALE RATS: NEOPLASMS (CONTINUED) 

CONTROL LOW DOSE HIGH DOSE
 

•PERIICNEUM	 (14) (35) (33 )
 

SARCOMA, NOS 4 (11%) 3 (9%)
 

FIBROMA 1 (3%)
 

FIBROSARCOMA 1 (3%) 3 (9%)
 

ALL OTHJER SYSTEMS 

•MULTIPLE ORGANS (35) (33) 

SARCOMA, NOS 1 (3%) 

FIBROSARCOMA 1 (3%) 

ANIMAL DISPOSITION SUHMAhi
 

ANIMALS INITIALLY IN STUDY 15 35 35
 

NATURAL DEATHS 10 10
 

MORIBUND SACRIFICE 7 7
 

SCHEDULED SACRIFICE
 

ACCIDENTALLY KILLED
 

TERMINAL SACRIFICE 11 18 18
 

ANIMAL MISSING
 

d INCLUDES AUT0LY2ED ANIMALS
 

TUMOR SUMMARY
 

TOTAL ANIMALS WITH PRIMARY TUTORS* 14 32 32
 

TOTAL PRIMARY TUMORS 19 54 59
 

TOTAL ANIMALS WITH BENIGN TUMORS 14 31 30
 

TOTAL BENIGN TUMORS 15 42 40
 

TOTAL ANIMALS WITH MALIGNANT TUMORS 12 16
 

TOTAL MALIGNANT TUMORS 12 19
 

TOTAL ANIMALS WITH SECONDARY TUMORS# 1
 

TOTAL SECONDARY TUMORS 1
 

TOTAL ANIMALS WITH TUMORS UNCERTAINBENIGN OR MALIGNANT
 

TOTAL UNCERTAIN TUMORS
 

TOTAL ANIMALS WITH TUMORS UNCERTAINPRIMARY OR METASTATIC
 

TOTAL UNCERTAIN TUMORS
 

* PRIMARY TUMORS: ALL TUMORS EXCEPT SECONDARY TUMORS
 

# SECONDARY TUMORS: METASTATIC TOMORS OR TUMORS INVASIVE INTO AN ADJACENT ORGAN
 

49
 
TABLE A2.

 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN FEMALE RATS 

FEODAPSONEINTHEDIET 

CONTROL LO» DCSE HIGH DOSE
 

ANIMALS INITIALLY IN STUDY 15 35 35
 

ANIMALS SECROPSIED 15 34 35
 

ANIMALS EXAMINED HISTOPATHOLOGICALLI 15 34 35
 

INTEGUMENTARY SYSTEM
 

•SUBCUT TISSUE	 (15) (34) (35)
 

SQUAMOUS CELL PAPILLOMA 1 (3%)
 

RESPIRATORY SYSTEM
 

NONE
 

HEMATOPOIETIC SYSTEM
 

NONE
 

CIRCULATORY SYSTEM
 

NONE
 

DIGESTIVE SYSTEM
 

NONE
 

URINARY SYSTEM
 

tKIDNEY (15) (34) (34)
 

ADENOCARCINOMA, NOS 1 (3%)
 

#URINARY BLADDER (15) (3D (33)
 

TRANSITIONAL-CELL CARCINOMA 1 (3%)
 

ENDOCBINE SYSTEM
 

•PITUITARY	 (15) (24) (30)
 

._£-I4flSL 5-iHSL IJLJIZII 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMEER OF ANIMALS NECROPSIED
 

50
 
TABLE A2. FEMALE RATS: NEOPLASMS (CONTINUED) 

CONTROL LOW DOSE HIGH DOSE
 

#THYFOIE (15) (32) (34)
 

ADENOCARCINOMA, NOS 1 (3%)
 

C-CELL ADENOMA 1 (3%)
 

HEPBOEUCTIVE SYSTEM
 

•MAMMARY	 GLAND (15) (34) (35)
 

ADENOMA, NCS 1 (3%)
 

FIBROADENOMA 1 (7%) 2 (6%) 1 (3%)
 

#UTERUS (14) (33) (34)
 

ADENOCARCINOMA, NOS 1 (7%)
 

ENDOMETRIAL STROMAL POLYP 3 (21%) 8 (24%) 2 (6%)
 

NERVOUS SYSTEM
 

NCNE
 

SPECIAL SENSE ORGANS
 

NONE
 

MUSCULOSKELETAL SYSTEM
 

NCNE
 

BODY C&VITIIS
 

NCNE
 

ALL OTHER SXSTEMS
 

• NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

51
 
TABLE A2. FEMALE RATS: NEOPLASMS (CONTINUED)

 

CONTROL LOW DOSE HIGH DOSE
 

ANIMAL DISPOSITION SUMMARY 

ANIMALS INITIALLY IN STUDY

NATURAL DEATHS

MORIBUND SACRIFICE

SCHEDULED SACRIFICE 

ACCIDENTALLY KILLED 

TERMINAL SACRIFICE

ANIMAL MISSING 

 15

 15

 35

 4

 31

 35 

2 

4 

 29 

3 INCLUDES AUTOLYZED ANIMALS 

TUMOR SUMMARY
 

TOTAL ANIMALS WITH ERIMARY TUMORS* 8 15 14
 

TOTAL PRIMARY TUMORS 11 20 15
 

TOTAL ANIMALS WITH BENIGN TUMORS 7 14 13
 

TOTAL BENIGN TUMORS 10 18 14
 

TOTAL ANIMALS WITH MALIGNANT TUMORS 1 2 1
 

TOTAL MALIGNANT TUMORS 1 2 1
 

TOTAL ANIMALS WITH SECONDARY TUMORSt
 

TOTAL SECONDARY TUMORS
 

TOTAL ANIMALS WITH TUMORS UNCERTAIN­ BENIGN OR MALIGNANT
 

TOTAL UNCERTAIN TUMORS
 

TOTAL ANIMALS WITH TUMORS UNCERTAIN­ PRIMARY OR METASTATIC
 

TOTAL UNCERTAIN TUMORS
 

* PRIMARY TUMORS: ALL TUMORS EXCEPT SECONDARY TUMORS
 

# SECONDARY TUMORS: METASTATIC TUMORS OR TUMORS INVASIVE INTO AN ADJACENT CRGAN
 

52 
APPENDIX B
 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN
 

MICE FED DAPSONE IN THE DIET
 

53
 

TABLE B1.

 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN MALE MICE 

FEDDAPSONEINTHEDIET 

CONTROL LOW DOSE HIGH DOSE 

ANIMALS INITIALLY IN STUDY 14 35 34 

ANIMALS MISSING 1 1 1 

ANIMALS NECROPSIED 11 33 33 

ANIMALS EXAMINED HXSTOPATHOLOGICALLY 11 33 32 

INTEGUMENTARY SYSTEM
 

•SKIN	 (11) (33) (33)
 

FIBROMA 1 (3%)
 

BESPIRATCRY SYSTEM
 

#LUNG (11) (33) (32)
 

ALVEOLAR/BRONCHIOLAR ADENOMA 5 (15%) 1 (3%)
 

HEMATOPOIETIC SYSTEM
 

NONE
 

CIRCULATORY SYSTEM
 

NONE
 

DIGESTIVE SYSTEM
 

«LIVEB (11) (33) (31)
 

HEPATOCELLULAR ADENOMA 6 (18%) 2 (6%)
 

URINARY SYSTEM
 

NONE
 

ENDOCRINE SYSTEM
 

•PITUITARY	 (7) (28) (16)
 

11611
 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

55
 
TABLE B1. MALE MICE: NEOPLASMS (CONTINUED)

 

#THYBOID
 

FOLLICULAR-CELL ADENOMA
 

REPRODUCTIVE SYSTEM
 

NCNE
 

NERVOUS SYSTEM
 

NCNE
 

SPECIAL SENSE ORGANS
 

•EYE/LACRIMAL	 GLAND
 

ADENCMA, NOS
 

MUSCULOSKELETAL SYSTEM
 

NONE
 

BODY CAVITIES
 

NONE
 

ALL OTHER SYSTEMS
 

NONE
 

ANIMAL DISPOSITION SUMMARY
 

ANIMAiS INITIALLY IN STUDY
 

NATURAL DEATHS
 

MORIBUND SACRIFICE
 

SCHEDULED SACRIFICE
 

ACCIDENTALLY KILLED
 

TERMINAL SACRIFICE
 

ANIMAL MISSING
 

INCLUDES AuTOkXZ ^
 

CONTROL LOW DOSE HIGH DOSE
 

(8)	 (30) (24)
 

1 (3%)
 

(11) (33) (33)
 

1 (3%)
 

14 35 

12 6 4 

3 7 

1 

24 22 

1 1 

* NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

• NUMBER OF ANIMALS SECROPSIED
 

56
 
TABLE B1. MALE MICE: NEOPLASMS (CONTINUED) 

CONTROL LOW DOSE HIGH DOSE
 

TOMOR SUMMARY
 

TOTAL ANIMALS WITH PRIMARY TUMORS* 11
 

TOTAL PRIMARY TUMORS 13
 

TOTAL ANIMALS WITH BENIGN TUMORS 11
 

TOTAL BENIGN TUMORS 13
 

TOTAL ANIMALS MITH MALIGNANT TUMORS
 

TOTAL MALIGNANT TUMORS
 

TOTAL ANIMALS WITH SECONDARY TUMORS#
 

TOTAL SECONDARY TUMORS
 

TOTAL ANIMALS WITH TUMORS UNCERTAIN­ BENIGN OR MALIGNANT
 

TOTAL UNCERTAIN TUMORS
 

TOTAL ANIMALS HITH TUMORS UNCERTAIN­ PRIMARY OR METASTATIC
 

TOTAL UNCERTAIN TUMORS
 

• PRIMARY TUMORS: ALL TUMORS EXCEPT SECONDARY TUMORS
 

# SECONDARY TUMORS; METASTATIC TUMORS OR TUMORS INVASIVE INTO AN ADJACENT ORGAN
 

57
 
TABLE B2.
 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN FEMALE MICE
 

FED DAPSONE IN THE DIET
 

CONTROL LOW DOSE HIGH DOSE
 

ANIMALS INITIALLY IN STUDY 14 35 36
 

ANIMALS HISSING 3
 

ANIMALS NECROPSIED 13 31 35
 

ANIMALS EXAMINED HISTOPATHOLOGICALLY 13 31 35
 

INTEGUMENTARY SYSTEM
 

*SUBCUT TISSUE (13) (31) (35)
 

FIBRCMA 1 (8%)
 

FIBROSARCOMA 1 (8%) 1 (3%)
 

RESPIRATORY SYSTEM
 

#LUNG (13) (30) (35)
 

ALVEOLAR/BRONCHIOLAR CARCINOMA 1 (8%)
 

HEMATOPOIETIC SYSTEM
 

•MULTIPLE ORGANS	 (13) (31) (35) 

MALIG.LYMPHOMA, LYMPHOCYTIC TYPE 1 (ΘΧ) 

MALIG.LYMPHOMA, HISTIOCYTIC TYPE 1 (3%) 

•PANCREATIC	 L.NODE (6) (1)
 

MALIG.LYMPHOMA, HISTIOCYTIC TYPE 1 (17%)
 

•LIVER	 (13) (30) (35)
 

GRANULOCYTIC LEUKEMIA 1 (8X)
 

CIRCULATORY SYSTEM
 

NONE
 

DIGESTIVE SYSTEM
 

NONE
 

URINARY SYSTEM
 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

58
 
TABLE B2. FEMALE MICE: NEOPLASMS (CONTINUED)

 

CONTROL LOW DOSE HIGH DOSE
 

ENDOCRINE SYSTEM
 

•PITUITARY	 (9) (25) (27)
 

ACIDOPHIL CARCINOMA 1 («)
 

REPRODUCTIVE SYSTEM
 

•MAMMARY	 GLAND (13) (31) (35)
 

ADENOCARCINOMA, NOS 1 (8*)
 

#UTERUS	 (13) (31) (35)
 

ENDOMETRIAL STROMAL POLYP 1 (3%)
 

NERVOUS SYSTEM
 

NONE
 

SPECIAL SENSE ORGANS
 

NONE
 

MUSCULOSKELETAL SYSTEM
 

NCNE
 

BODY CAVITIES
 

•PERITONEUM	 (13) (31) (35)
 

SARCOMA, NOS 1 (3%)
 

ALL OTHER SYSTEMS
 

•MULTIPLE ORGANS	 (13) (31) (35)
 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

• NUMBER OF ANIMALS NECROPSIED
 

59
 
TABLE B2. FEMALE MICE: NEOPLASMS (CONTINUED)

 

ANIMAL DISPOSITION SUMMARY
 

ANIMALS INITIALLY IN STUDY


NATURAL DEATHS


MORIEUND SACRIFICE


SCHEDULED SACRIFICE
 

ACCIDENTALLY KILLED


TERMINAL SACRIFICE


ANIMAL MISSING


d INCLUDES AUTOLYZED ANIMALS
 

TUMOR SUMMARY
 

TOTAL ANIMALS WITH fRIMARY TUMORS*


TOTAL PRIMARY TUMORS


TOTAL ANIMALS WITH BENIGN TUMORS


TOTAL BENIGN TUMORS


TOTAL ANIMALS WITH MALIGNANT TUttOHS


TOTAL MALIGNANT TUMORS


TOTAL ANIMALS WITH SECONDARY TUMORS*
 

TOTAL SECONDARY TUMORS
 

TOTAL ANIMALS WITH TUMORS UNCERTAIN­ BENIGN OR MALIGNANT
 

TOTAL UNCERTAIN TUMORS
 

TOTAL ANIMALS WITH TUMORS UNCERTAIN­ PRIMARY OR METASTATIC
 

TOTAL UNCERTAIN TUMORS
 

CONTROL


 14


 4


 4


 6


 6


 7


 1


 1


 5


 6


 LOS DOSE HIGH DOSE
 

 35 36
 

 14 8
 

9 17
 

2
 

7 11
 

3
 

4 2
 

4 2
 

1
 

1
 

3 2
 

3 2
 

* PRIMARY TUMORS: ALL TUMORS EXCEPT SECONDARY TUMORS
 

t SECONDARY TUMORSi METASTATIC TUMORS OR TDMORS INVASIVE INTO AN ADJACENT ORGAN
 

60
 
APPENDIX C
 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS
 

IN RATS FED DAPSONE IN THE DIET
 

61
 

TABLE CI.

 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN MALE RATS 

FEDDAPSONEINTHEDIET 

CONTROL LOW DOSE
 

ANIMALS INITIALLY IN STUDY 15 35
 

ANIMALS NECROPSIED 14 35
 

ANIMALS EXAMINED HISTOPATHOLOGICALLY 14 35
 

INTEGUMENTARY SYSTEM
 

NONE
 

RESPIRATORY SYSTEM
 

«TRACHEA (14) (35)
 

INFLAMMATION, SUPPURATIVE 1 (7%)
 

INFLAMMATION, ACUTE/CHRONIC
 

INFLAMMATION, CHRONIC 1 (7%) 1 (3%)
 

INFLAMMATION, CHRONIC SUPPURATIV 1 (7%) 6 (17%)
 

«LUNG/BRONCHIOLE (14) (34)
 

HYPERPLASIA, LYMPHOID 1 (7%) 1 (3%)
 

#LUNG (14) (34)
 

INFLAHHATION, INTERSTITIAL
 

INFLAMMATION, CHRONIC SUPPORATIV 1 (3%)
 

BRONCHOPNEUMONIA CHRONIC SUPPURA
 

HEMATOPOIETIC SYSTEM
 

«BONE HARROW (13) (32)
 

ATROPHY, NOS 5 (38%) 3 (9%)
 

«SPLEEN (14) (34)
 

CONGESTION, NOS 1 (3%)
 

HEMORRHAGE 3 (9%)
 

FIBROSIS 3 (9%)
 

NECROSIS, NOS
 

DEPOSIT, NOS 1 (3%)
 

ATROPHY, NOS 1 (3%)
 

METAPLASIA, OSSEOUS
 

HEMATOPOIESIS 1 (3%)
 

CIRCULATORY SYSTEM
 

« NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

• NUHBEB OF ANIMALS NECROPSIED
 

63
 

HIGH


35
 

33
 

33
 

(31)
 

7
 

1
 

1
 

1
 

(31)
 

2
 

(31)
 

1
 

 DOSE
 

(23%)
 

(3%)
 

(3%)
 

(3%)
 

(6%)
 

(3%)
 

1 (3%)
 

(28)
 

2
 

(32)
 

3
 

3
 

1
 

3
 

6
 

2
 

(7%)
 

(9%)
 

(9%)
 

(3%)
 

(9%)
 

(19%)
 

(6%)
 
TABLE CI. MALE RATS: NONNEOPLASTIC LESIONS (CONTINUED)

 

CONTROL LOW DOSE HIGH DOSE
 

DIGESTIVE SYSTEM
 

#LIVER (14) (35) (32)
 

NECROSIS, FOCAL 1 (3%)
 

CYTOPLASMIC VACUOLIZATION 1 (3%)
 

HEMATOPOIESIS 1 (3%)
 

#LIVER/CENTRILOBULAR (14) (35) (32)
 

NECROSIS, NOS 2 (6%) 1 (3%)
 

NECRCSIS, DIFFUSE 1 (3*)
 

•BILE DUCT	 (14) (35) (33)
 

HYPERPLASIA, NOS 1 (3%)
 

tPANCREAS (14) (33) (32)
 

METAPLASIA, OSSEOUS 1 (3%)
 

#PANCREATIC ACINUS (14) (33) (32)
 

ATROPHY, NOS 1 (7%)
 

URINARY SYSTEM
 

#KIDNEY (14) (35) (32)
 

INFLAMMATION, INTERSTITIAL 5 (16%)
 

INFLAMMATION, CHRONIC 14 (100%) 22 (63%) 15 (47%)
 

ENDOCRINE SYSTEM
 

#ADRENAL CORTEX (14) (35) (32)
 

HYPERPLASIA, NOS 1 (3X)
 

#THYROID (14) (33) (28)
 

HYPERPLASIA, FOLLICULAR-CELL 1 (4%)
 

REPRODUCTIVE SYSTEM
 

•MAMMARY	 GLAND (14) (35) (33)
 

CYST, NOS 1 (3%)
 

#PROSTATE (13) (31) (27)
 

INFLAMMATION, SUPPURATIVE 1 (4%)
 

•SEMINAL VESICLE (14) (35) (33)
 

_ -IMIAMMATION, SUPfUSATiV? 1 13})
 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

• NUMBER OF ANIMALS NECfiOPSIED
 

64
 
TABLE C1. MALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

CONTROL LOW DOSE HIGH DOSE
 

#TESTIS (35) (31)
 

LYMPHOCYTIC INFILTRATE 1 (3X) 2 (6%)
 

NECROSIS, FAT 1 (7%)
 

NERVOUS SYSTEM
 

NONE
 

SPECIAL SENSE ORGANS
 

•EYE/CRYSTALLINE	 LENS (14) (35) (33)
 

MLNERALIZATION 1 (7%)
 

MUSCULOSKELETAL SYSTEM
 

NONE
 

BODY CAVITIES
 

•PERITONEUM	 (14) (35) (33) 

INFLAMMATION, CHRONIC 1 (3%) 

FIBROSIS 2 (6S) 

METAPLASIA, OSSEOUS 2 (6X) 1 (3X) 

•PERITONEAL	 CAVITY (14) (35) (33)

 

METAPLASIA, OSSEOUS 1 (3X)

 

•MESENTERY	 (14) (35) (33)

 

METAPLASIA, OSSEOUS 1 (3X)

 

ALL OTHER SYSTEMS
 

•MULTIPLE	 ORGANS d<0 (35) (33)
 

METAPLASIA, OSSEOUS 1 (3%)
 

SPECIAL UORPHOLOGY SUMMARY
 

NO LESION REPORTED
 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

• NUMBER OF ANIMALS NECROPSIED
 

65
 
TABLE C2.
 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN FEMALE RATS
 

FEDDAPSONEINTHEDIET
 

CONTROL LCW DCSE
 

ANIMALS INITIALLY IN STUDY 15 35
 

ANIMALS KECBOPSIED 15 34
 

ANIMALS EXAMINED HISTOPATHOLOGICALLY 15 34
 

INTEGUMENTARY SYSTEM
 

NCNE
 

RESPIRAICRY SYSTEM 

tTRACHEA 

LYMPHOCYTIC INFILTBATE 

INFLAMMATION, SUPPUBATIVE 

INFLAMMATION, CHRONIC 

INFLAMMATION, CHRONIC SUPPURATIV 

(15) 

2 (13%) 

(34) 

1 

3 

(3%) 

(9%) 

#LUNG/BRONCHIOLE 

HYPERPLASIA, LYMPHOID 

(15) 

2 (13%) 

(33) 

1 (3%) 

«LUNG 

INFLAMMATION, INTERSTITIAL 

BRONCHOPNEUMONIA CHfiONIC SUPPURA 

(15) (33) 

HEMATOPOIETIC SYSTEM
 

«BONE MARROW (14) (33)
 

ATROPHY, NOS 8 (57%) 20 (61%)
 

«SPLEEN (15) (33)
 

HEMATOPOIESIS 1 (7%) 1 (3%)
 

CIRCOLATOBY SYSTEM
 

NONE
 

DIGESTIVE SYSTEM
 

«LIVER/PERIPORTAL (15) (34)


L.1Z4L
 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS ΝECBOPSIED
 

HIGH DOSE
 

35
 

35
 

35
 

(34)
 

1 (3%)
 

2 (6%)
 

1 (3%)
 

(35)
 

2 (6%)
 

(35)
 

4 (11%)
 

1 (3%)
 

(3 5)
 

22 (6 3%)
 

(34)
 

 (34)
 

66
 
TABLE C2. FEMALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

HIGH DOSE
 

(34)
 

1 (3%)
 

(34)
 

4 (12%)
 

1 (3%)
 

(34)
 

(35)
 

(34)
 

2 (6%)
 

1 (3%)
 

(34)
 

7 (21%)
 

4 (12%)
 

(34)
 

1 (3%)
 

1 (3%)
 

(34)
 

(34)
 

(34)
 

J-ilSL.
 

#£ANCREATIC ACINUS
 

ATROPHY, NOS
 

URINARY SYSTEM
 

#KIDNEY
 

INFLAMMATION, CHRONIC
 

INFLAMMATION, CHRONIC


ENDOCRINE SYSTEM
 

#ADRENAL
 

ANGIECTASIS
 

REPRODUCTIVE SYSTEM
 

•MAMMABY	 GLAND
 

CYST# NOS
 

#UTERUS
 

EDEMA, NOS
 

PYCMETfiA
 

#UTERU£/ENDOMETRIUM
 

 SUPPURATIV
 

INFLAMMATION,
 

INFLAMMATION,
 

HYPERPLASIA,
 

HYPERPLASIA,
 

#OVARY/OVIDUCT
 

INFLAMMATION,
 

INFLAMMATION,
 

#OVARY
 

CYST, NOS
 

INFLAMMATION,
 

#OVARY/MEDULLA
 

HYPERPLASIA,
 

NERVOUS SYSTEM
 

#BRAIN
 

MALACIA
 

SUPPURATIVE
 

CHRONIC SUPPURATIV
 

NOS
 

CYSTIC
 

SUPPURATIVE
 

CHRONIC SUPPURATIV
 

SUPPURATIVE
 

NOS
 

CONTROL
 

(15)
 

1 (7%)
 

(15)
 

13 (87%)
 

(15)
 

(15)
 

(14)
 

(14)
 

7 (50%)
 

1 (7%)
 

6 (43%)
 

(14)
 

(14)
 

(14)
 

1 (7%)
 

(15)
 

LOW DOSE
 

(33)
 

(34)
 

16 (47%)
 

(34)
 

1 (3%)
 

(34)
 

6 (18%)
 

(33)
 

11	 (33%)
 

2 (6%)
 

(33)
 

(33)
 

3 (9%)
 

1 (3%)
 

(33)
 

(31)
 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROFSIED
 

67
 
TABLE C2. FEMALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

CONTROL LOW DOSE HIGH DOSE
 

SPECIAL SENSE ORGANS
 

•EYE/CBYSTALLINE	 LENS (15) (34) (35)
 

MINERALIZATION 1 OX)
 

MUSCULOSKELETAL SYSTEM
 

NONE
 

BODY CAVITIES
 

•PERITCNEUM	 (15) (34) (35) 

INFLAMMATION# CHBONIC 1 (3%) 

•MESENTERY	 (15) (34) (35)

 

NECROSIS, FAT 1 (3%)

 

ALL OTHER SYSTEMS
 

NONE
 

SPECIAL BORPHOLOGY SUMMARY
 

NO LESION REPORTED
 

AUTOLYSIS/NO NECROPSY
 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

68
 
APPENDIX D
 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS
 

IN MICE FED DAPSONE IN THE DIET
 

69
 

TABLE D1.

 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN MALE MICE FED 

DAPSONE IN THE DIET 

CONTROL LOW DCSE HIGH DOSE
 

ANIMALS INITIALLY IN STUDY 14 35 34
 

ANIMALS HISSING 1 1 1
 

ANIMALS &ECRCPSIED 11 33 33
 

ANIMALS EXAMINED HISTOPATHOLOGICALLY 11 33 32
 

INTEGUMENTARY SYSTEM
 

•SKIN	 (11) (33) (33)
 

INFLAMMATION, SUPPURATIVE 1 (3%)
 

FIBROSIS 1 (3%)
 

RESPIRATORY SYSTEM
 

#LUNG/ERONCHIOLE 1) (33) (32)
 

HYPERPLASIA, PLASMA CELL 1 (3%)
 

HYPERPLASIA, LYMPHOID 2 (6%)
 

#LUNG 1) (33) (32)
 

INFLAMMATION, INTERSTITIAL 4 (13%)
 

INFLAMMATION, SUPPURATIVE 1 (3%)
 

BRONCHOPNEUMONIA SUPPURATIVE 5 (15%) 4 (13%)
 

ABSCESS, NOS 2 (18%)
 

BRCNCHOENEUMONIA CHRONIC SUPPURA 6 (55%) 5 (16%)
 

HEMATOPOIETIC SYSTEM
 

«SPLEEN (9) (33) (32)
 

CONTRACTURE 1 (3%)
 

HEMORRHAGE 2 (6%)
 

HYPERPLASIA, LYMPHOID 1 (3%) 1 (3%)
 

HEMATOPOIESIS 2 (6%) 2 (6%)
 

•MESENTERIC L.	 NODE (1) (7) (6)
 

CONGESTION, NOS 1 (14%) 3 (50%)
 

HEMORRHAGE 1 (17%)
 

HYPERPLASIA, LYMPHOID 2 (29%) 1 (17%)
 

HEMATOPOIESIS 1 (14%)
 

CIRCULATOHY SiSTEB
 

•MYOCARDIUM	 (11) (33) (32)
 

* NOHBEH OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECBOPSIED
 

71
 
TABLE D1. MALE MICE: NONNEOPLASTIC LESIONS (CONTINUED)
 

CONTROL LOW DOSE HIGH DOSE
 

INFLAMMATION, CHRONIC 1 (3%)
 

FIBROSIS, DIFFUSE 1 (3%)
 

DIGESTIVE SYSTEM 

#LIVER	 (U)
 (33) (31) 

FIBROSIS, FOCAL 1 13%)
 

NECROSIS, NOS 1 (3%)
 

HYPERPLASIA, NODULAR 2 (6%)
 

ANGIECTASIS 1 (3%)
 

HYPEEPLASIA, LYMPHOID 1 (3%)
 

«LIVrR/CENTRILOBULAR f Ί l > (33) (31)
 

NECROSIS, NOS 1 (3%) 1 (3%)
 

•BILE DUCT	 (11) (33) (33)
 

CYST, NOS 1 (3%)
 

«ESOPHAGUS (6) (33) (30)
 

ABSCESS, NOS 1 (3%)
 

«DUODENUM (6) .(3 3) (32)
 

HYPERPLASIA, ADENOMATOUS 1 (3%)
 

URINARY SYSTEM
 

«URINARY BLADDER (9) (32) (32)
 

MUCOCELE 1 (3%)
 

ENDOCRINE SYSTEM
 

NONE
 

REPRODUCTIVE SYSTEM
 

NONE
 

NERVOUS SYSTEM
 

NONE
 

SPECIAL SENSE ORGANS
 

« NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 • NUMBER OF ANIMALS NECBOPSIED
 

72
 
TABLE D1. MALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

CONTROL LOW DOSE HIGH DOSE
 

MUSCULOSKELETAL SYSTEM
 

NCNE
 

BODY CAVITIES
 

NCNE
 

ALL OTHER SYSTEMS
 

NONE
 

SPECIAL KORPHOLOGY SUMMARY
 

NO LESION REPORTED 5 13 10
 

ANIMAL MISSING/NO NECROPSY 1 1 1
 

ACCIDENTAL DEATH 1
 

NECROPSY PERF/NO HISTO PERFORMED 1
 

AUTOLYSIS/NO NECROPSY 2
 

73
 
TABLE D2.

 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN FEMALE MICE 

FEDDAPSONE INTHEDIET 

CONTROL LOW DOSE HIGH DOSE
 

ANIMALS INITIALLY IN STUDY 14 35 36
 

ANIMALS MISSING 3
 

ANIMALS NECROPSIED 13 31 35
 

ANIMALS EXAMINED HISTOPATHOLOGICALLY 13 31 35
 

INTEGUMENTARY SYSTEM
 

NONE
 

RESPIRATORY SYSTEM
 

#TRACHEA (13) (30) (35) 

INFLAMMATION, SUPPURATIVE 1 (8%) 1 (3%) 3 (9%) 

INFLAMMATION, CHRONIC SUPPURATIV 1 (3%) 

#LUNG (13) (30) (35) 

INFLAMMATION# INTERSTITIAL 1 (3%) 

PNEUMONIA, LIPID 1 (3%) 

BRCNCHOENEUMONIA SUPPURATIVE 9 (69%) 16 (5 3%) 16 (46%) 

ABSCESS, NOS 2 (7%) 

BRONCHOPNEUMONIA CHRONIC SUPPURA 6 (20%) 5 (14%) 

INFLAMMATION, FOCAL GRANULOMATOU 1 (3%) 

CHOLESTEROL DEPOSIT 1 (3%) 

HEMATOPOIETIC SYSTEM
 

•SPLEEN	 (13) (28) (34) 

HYPERPLASIA, LYMPHOID 2 (7%) 

HEMATOPOIESIS 3 (23%) 5 (18%) 3 (9%) 

•PULMONARY LYMPH NODE	 (6) (1)

 

INFLAMMATION, SUPPURATIVE 1 (17%)

 

#ABDOMINAL LYMPH NODE (6) (1)

 

HEMATOPOIESIS 1 (17%)

 

•PANCREATIC L.NODE	 (6) (1)

 

HYPERPLASIA, LYMPHOID 2 (33%)

 

•MESENTERIC L. NODE	 (6) (1) 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

74
 
TABLE D2. FEMALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

CONTROL LOW DOSE
 

CIRCULA1CRY SYSTEM
 

NONE
 

DIGESTIVE SYSTEM
 

#LIVER (13) (30)
 

ANGIECTASIS 1 (3%)
 

HEMATOPOIESIS 2 (7%)
 

#LIVER/CENTRILOBULAR (13) (30)
 

NECROSIS, NOS 1 (8%) 1 (3%)
 

•BILE DUCT	 (13) (31)
 

CYST, NOS 1 (8%)
 

#PANCREATIC ACINUS (13) (29)
 

ATROPHY, NOS 1 (8%)
 

URINABY SYSTEM
 

#KIDNEY (13) (31)
 

AMYLOIDOSIS 1 (8%)
 

ENDOCRINE SYSTEM
 

NONE
 

REPfiCDUCIIVE SYSTEM
 

#UTERUS (13) (31)
 

ABSCESS, NOS 1 (3%)
 

•UTERUS/ENDOMETRIUM	 (13) (31)
 

INFLAMMATION, SUPPURATIVE 3 (23%) 3 (10%)
 

INFLAMMATION, CHRONIC SUPPURATIV 1 (3%)
 

HYPERPLASIA, CYSTIC 5 (38%) 16 (52%)
 

#OVARY (13) (30)
 

ABSCESS, NOS 1 (8%)
 

INFLAMMATION, CHRONIC SUPPURATIV 1 (8%)
 

NERVOUS SYSTEM
 

NONE
 

HIGH DOSE
 

(35)
 

(35)
 

(35)
 

(34)
 

(35)
 

(35)
 

(35)
 

2 (6%)
 

17 (49%)
 

(35)
 

75
 
TABLE D2. FEMALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

CONTROL LOW DOSE HIGH DOSE 

SPECIAL SENSE ORGANS 

NONE 

MUSCULOSKELETAL SYSTEM 

NONE 

BODY CAVITIES 

•MESENTERY

MINERALIZATION

NECRCSIS, NOS

 (13)

 1 (8%) 

 1 (8%) 

 (31) (35) 

ALL OTHEB SYSTEMS 

NONE 

SPECIAL £CRFHOLCGY SUMMARY 

NO LESION REPORTED

ANIMAL MISSING/NO NECROPSY

ACCIIENTAL DEATH

AUTOLYSIS/NO NECROPSY

# NUMBER OF ANIMALS iITH TISSUE EXAMINED

• NUMBER OF ANIMALS NECBOPSIED 

1

 MICROSCOPICALLY 

3

 3 

1 

5 

1 

76
 
APPENDIX E
 

ANALYSES OF THE INCIDENCE OF PRIMARY TUMORS
 

IN RATS FED DAPSONE IN THE DIET
 

77
 

Table El. Analyses of the Incidence of Primary Tumors in Male Rats Fed Dapsone in the Dieta
 

Topography: Morphology 

Matched 

Control 

Hematopoietic System: 

Malignant Lymphoma*3 0/14 (0.00) 

 Values0 > d N.S. 

Departure from Linear Trende = 0.022 

Relative Risk (Matched Control)f 

Lower Limit 

Upper Limit 

VD Relative Risk (Pooled Control)f 

Lower Limit 

Upper Limit 

Weeks to First Observed Tumor — 

Pooled 

Control 

Low 

Dose 

High 

Dose 

0/44 (0.00) 4/35 (0.11) 0/33 (0.00) 

N.S. = 0.035** N.S. 

 = 0.003 

Infinite 

0.400 

Infinite 

Infinite 

1.170 

Infinite 

— 71 — 
Table El. Analyses of the Incidence of Primary Tumors in Male Rats Fed Dapsone in the Dieta
 

(continued) 

Topography: Morphology 

Matched 

Control 

Pooled 

Control 

Low 

Dose 

High 

Dose 

Hematopoietic

Lymphoma or

 System: 

 Leukemia 1/14 (0.07) 1/44 (0.02) 4/35 (0.11) 0/33 (0.00) 

 Values 0 >d N.S. N.S. N.S. N.S. 

Departure from Linear Trende = 0.015 

Relative Risk (Matched Control)f 

Lower Limit 

Upper Limit 

1.600 

0.183 

76.389 

0.000 

0.000 

7.860 

oo Relative Risk (Pooled Control)f 

Lower Limit 

Upper Limit 

5.029 

0.525 

239.834 

0.000 

0.000 

24.636 

Weeks to First Observed Tumor 106 — 71 
Table El. Analyses of the Incidence of Primary Tumors in Male Rats Fed Dapsone in the Dieta 

(continued) 

Topography: Morphology 

Matched 

Control 

Pooled 

Control 

Low 

Dose 

High 

Dose 

Spleen: Fibroma*5 0/14 (0.00) 0/43 (0.00) 6/34 (0.18) 10/32 (0.31) 

 Values0 > d 

 ­ 0.012 < 0.001 = 0.006** < 0.001** 

 ­ 0.016* 

Relative Risk (Matched Control) 

Lower Limit 

Upper Limit 

f Infinite 

0.710 

Infinite 

Infinite 

1.406 

Infinite 

0 0 

Relative Risk (Pooled Control)f 

Lower Limit 

Upper Limit 

Infinite 

2.041 

Infinite 

Infinite 

4.044 

Infinite 

Weeks to First Observed Tumor __ 69 91 

Spleen: Fibrosarcoma*5 0/14 (0.00) 0/43 (0.00) 0/34 (0.00) 3/32 (0.09) 

 Valuesc > d N.S. - 0.023 N.S. N.S. 

Relative Risk (Matched Control) 

Lower Limit 

Upper Limit 

f Infinite 

0.281 

Infinite 

Relative Risk (Pooled Control)f 

Lower Limit 

Upper Limit 

Infinite 

0.815 

Infinite 

Weeks to First Observed Tumor — — — 95 
Table El· Analyses of the Incidence of Primary Tumors in Male Rats Fed Dapsone in the Dieta
 

(continued) 

Topography; Morphology 

Matched 

Control 

Spleen: Sarcoma, NOSb 0/14 (0.00) 

 Values0 > d N.S. 

Relative Risk (Matched Control)f 

Lower Limit 

Upper Limit 

Relative Risk (Pooled Control)f 

Lower Limit 

Upper Limit 

00 

N> Weeks to First Observed Tumor 

Spleen: Fibroma, Fibrosarcoma, or Sarcoma, NOS 0/14 (0.00) 

 Values°>d 

 = 0.001 

Relative Risk (Matched Control)f 

Lower Limit 

Upper Limit 

Relative Risk (Pooled Control)f 

Lower Limit 

Upper Limit 

Weeks to First Observed Tumor 

Pooled 

Control 

Low 

Dose 

High 

Dose 

0/43 (0.00) 0/34 (0.00) 3/32 (0.09) 

 = 0.023 N.S. N.S. 

Infinite 

0.281 

Infinite 

Infinite 

0.815 

Infinite 

94 

0/43 (0.00) 6/34 (0.18) 14/32 (0.44) 

 < 0.001 = 0.006** < 0.001** 

 = 0.002* 

Infinite 

0.710 

Infinite 

Infinite 

2.067 

Infinite 

Infinite 

2.041 

Infinite 

Infinite 

5.948 

Infinite 

69 91 
idence of Primary 

(continued) 

Topography; Morphology 

Matched 

Control 

Pituitary :

Adenoma 

 Chromophobe 

1/14 (0.07) 

 Values0 >d N.S. 

Relative Risk (Matched Control)f 

Lower Limit 

Upper Limit 

00 

u> 

Relative Risk (Pooled Control)f 

Lower Limit 

Upper Limit 

Weeks to First Observed Tumor 106 

Pituitary :

Carcinoma 

 Chromophobe 

0/14 (0.00) 

 Values0 >d N.S. 

Relative Risk (Matched Control)f 

Lower Limit 

Upper Limit 

Relative Risk (Pooled Control)f 

Lower Limit 

Upper Limit 

Weeks to First Observed Tumor 

Tumors in Male
 

Pooled
 

Control
 

2/38 (0.05)
 

N.S.
 

1/38 (0.03)
 

N.S.
 

Rats Fed Dapsone
 

Low
 

Dose
 

2/28 (0.07)
 

N.S.
 

1.000
 

0.059
 

56.851
 

1.357
 

0.104
 

17.616
 

93 

0/28 (0.00)
 

N.S.
 

0.000
 

0.000
 

24.944
 

in the Dieta
 

High
 

Dose
 

2/28 (0.07)
 

N.S.
 

1.000
 

0.059
 

56.851
 

1.357
 

0.104
 

17.616
 

104 

2/28 (0.07)
 

N.S.
 

Infinite
 

0.157
 

Infinite
 

2.714
 

0.148
 

154.152
 

95
 
Table El· Analyses of the Incidence of Primary Tumors in Male Rats Fed Dapsone in the Dieta
 

(continued) 

Topography: Morphology 

Matched 

Control 

Pituitary: Chromophobe 

Adenoma or Carcinoma 1/14 (0.07) 

 Valuesc > d N.S. 

Relative Risk (Matched Control)f 

Lower Limit 

Upper Limit 

o°

Relative Risk (Pooled Control)f 

Lower Limit 

 Upper Limit 

Weeks to First Observed Tumor 106 

Thyroid: C-cell Carcinomab 1/14 (0.07) 

 Values0 > d N.S. 

Relative Risk (Matched Control)f 

Lower Limit 

Upper Limit 

Relative Risk (Pooled Control)f 

Lower Limit 

Upper Limit 

Weeks to First Observed Tumor 106 

Pooled
 

Control
 

3/38 (0.08)
 

N.S.
 

—_
 

2/44 (0.05)
 

N.S.
 

—
 

Low
 

Dose
 

2/28 (0.07)
 

N.S.
 

1.000
 

0.059
 

56.851
 

0.905
 

0.079
 

7.325
 

93
 

1/33 (0.03)
 

N.S.
 

0.424
 

0.006
 

32.328
 

0.667
 

0.012
 

12.197
 

105
 

High
 

Dose
 

4/28 (0.14)
 

N.S.
 

2.000
 

0.229
 

94.585
 

1.810
 

0.329
 

11.364
 

95
 

1/28 (0.04)
 

N.S.
 

0.500
 

0.007
 

37.877
 

0.786
 

0.014
 

14.261
 

104
 
(continued)
 

Topography: Morphology
 

Thyroid: C-cell Adenoma or
 

Carcinoma
 

 Values0>d
 

Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 oo
 

Ln
 

Weeks to First Observed Tumor
 

Testis: Interstitial-cell
 

Tumorb
 

 Values0>d
 

Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

:idence of Primary
 

Matched
 

Control
 

1/14 (0.07)
 

N.S.
 

106
 

14/14 (1.00)
 

N.S.
 

89
 

Tumors in Male
 

Pooled
 

Control
 

3/44 (0.07)
 

N.S.
 

38/44 (0.86)
 

N.S.
 

—
 

Rats Fed Dapsone
 

Low
 

Dose
 

2/33 (0.06)
 

N.S.
 

0.848
 

0.049
 

48.540
 

0.889
 

0.077
 

7.282
 

105
 

29/35 (0.83)
 

N.S.
 

0.829
 

0.000
 

1.122
 

0.959
 

0.784
 

1.169
 

71
 

in the Diet a
 

High
 

Dose
 

1/28 (0.04)
 

N.S.
 

0.500
 

0.007
 

37.877
 

0.524
 

0.010
 

6.092
 

104
 

28/31 (0.90)
 

N.S.
 

0.903
 

0.000
 

1.133
 

1.046
 

0.858
 

1.204
 

75
 
Table El. Analyses of the Incidence of Primary
 

(continued)
 

Matched
 

Topography: Morphology Control
 

Peritoneum: Sarcoma, NOS^ 0/14 (0.00)
 

 Values0>d N.S.
 

Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

0 0 

Weeks to First Observed Tumor
 

Peritoneum: Fibrosarcoma'5 0/14 (0.00)
 

 Values0>d N.S.
 

Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor —
 

Tumors in Male
 

Pooled
 

Control
 

0/44 (0.00)
 

N.S.
 

0/44 (0.00)
 

 = 0.037
 

—
 

Rats Fed Dapsone
 

Low
 

Dose
 

4/35 (0.11)
 

 = 0.035**
 

Infinite
 

0.400
 

Infinite
 

Infinite
 

1.170
 

Infinite
 

80
 

1/35 (0.03)
 

N.S.
 

Infinite
 

0.022
 

Infinite
 

Infinite
 

0.068
 

Infinite
 

105
 

in the Dieta
 

High
 

Dose
 

3/33 (0.09)
 

N.S.
 

Infinite
 

0.273
 

Infinite
 

Infinite
 

0.808
 

Infinite
 

95
 

3/33 (0.09)
 

N.S.
 

Infinite
 

0.273
 

Infinite
 

Infinite
 

0.808
 

Infinite
 

84
 
Table El. Analyses of the Incidence of Primary Tumors in Male Rats Fed Dapsone in the Dieta
 

(continued)
 

Topography: Morphology 

Matched 

Control 

Pooled 

Control 

Low 

Dose 

High 

Dose 

Peritoneum: Fibrosarcoma 

or Sarcoma, NOS 0/14 (0.00) 0/44 (0.00) 5/35 (0.14) 6/33 (0.18) 

 Values0 > d N.S. = 0.006 = 0.014** = 0.005** 

Relative Risk (Matched Control)f 

Lower Limit 

Upper Limit 

Infinite 

0.543 

Infinite 

Infinite 

0.732 

Infinite 

00 

Relative Risk (Pooled Control)f 

Lower Limit 

Upper Limit 

Infinite 

1.599 

Infinite 

Infinite 

2.151 

Infinite 

Weeks to First Observed Tumor — — 80 84 

a

Treated groups received doses of 600 or 1,200 ppm.
 

^Number of tumor-bearing animals/number of animals examined at site (proportion).
 

c

Beneath the incidence of tumors in a control group is the probability level for the Cochran-


Armitage test when Ρ < 0.05; otherwise, not significant (N.S.) is indicated. Beneath the
 

incidence of tumors in a treated group is the probability level for the Fisher exact test for
 

the comparison of that treated group with the matched-control group (*) or with the pooled-


control group (**) when Ρ < 0.05 for either control group; otherwise, not significant (N.S.)
 

is indicated.
 

d

A negative trend (N) indicates a lower incidence in a treated group than in a control group.
 

e

The probability level for departure from linear trend is given when Ρ < 0.05 for any comparison.
 

95% confidence interval of the relative risk between each treated group and the specified
 

control group.
 
Table E2. Analyses of the Incidence of Primary Tumors in Female Rats Fed Dapsone in the Dieta
 

Topography: Morphology 

Matched 

Control 

Pooled 

Control 

Low 

Dose 

High 

Dose 

Pituitary:

Adenoma 

 Chromophobe 

6/15 (0.40) 9/39 (0.23) 5/24 (0.21) 11/30 (0.37) 

 Values0 > d N.S. N.S. N.S. N.S. 

Relative Risk (Matched Control)f 

Lower Limit 

Upper Limit 

0.521 

0.161 

1.713 

0.917 

0.409 

2.499 

00 

00 

Relative Risk (Pooled Control)f 

Lower Limit 

Upper Limit 

0.903 

0.265 

2.587 

1.589 

0.686 

3.702 

Weeks to First Observed Tumor 106 _— 105 101 

Thyroid: C-cell Adenomab 0/15 (0.00) 0/41 (0.00) 1/32 (0.03) 0/34 (0.00) 

 Valuesc > d N.S. N.S. N.S. N.S. 

Relative Risk (Matched Control)f 

Lower Limit 

Upper Limit 

Infinite 

0.026 

Infinite 

Relative Risk (Pooled Control)f 

Lower Limit 

Upper Limit 

Infinite 

0.069 

Infinite 

Weeks to First Observed Tumor — — 105 — 
00 

Table E2. Analyses of the Incidence of Primary Tumor
 'umorss in Female
 

(continued)
 

Topography; Morphology
 

Mammary Gland: Fibroadenoma
 

or Adenoma, NOSb
 

 Values0>d
 

Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Uterus: Endometrial Stromal
 

Polypb
 

 Values0>d
 

Relative Risk (Matched Control)
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Matched Pooled 

Control Control 

1/15 (0.07) 9/44 (0.20) 

N.S. = 0.008(N) 

106 

3/14 (0.21) 6/43 (0.14) 

N.S. N.S. 

106 

Rats Fed Dapsone
 

Low
 

Dose
 

2/34 (0.06)
 

N.S.
 

0.882
 

0.051
 

50.522
 

0.288
 

0.032
 

1.274
 

93
 

8/33 (0.24)
 

N.S.
 

1.131
 

0.335
 

5.920
 

1.737
 

0.583
 

5.440
 

93
 

in the Dieta
 

High
 

Dose
 

1/35 (0.03)
 

 = 0.019**(N)
 

0.429
 

0.006
 

32.715
 

0.140
 

0.003
 

0.931
 

105
 

2/34 (0.06)
 

N.S.
 

0.275
 

0.026
 

2.190
 

0.422
 

0.044
 

2.175
 

105
 
Table E2. Analyses of the Incidence of Primary Tumors in Female Rats Fed Dapsone in the Dieta
 

(continued)
 

a

Treated groups received doses of 600 or 1200 ppm.
 

^Number of tumor-bearing animals/number of animals examined at site (proportion).
 

c

Beneath the incidence of tumors in a control group is the probability level for the Cochran-


Armitage test when Ρ < 0.05; otherwise, not significant (N.S.) is indicated. Beneath the incidence of tumors in a treated group is the probability level for the Fisher exact test for the
 

comparison of that treated group with the matched-control group (*) or with the pooled-


control group (**) when Ρ < 0.05 for either control group; otherwise, not significant
 

(N.S.) is indicated.
 

^A negative trend (N) indicates a lower incidence in a treated group than in a control group.
 

e

The probability level for departure from linear trend is given when Ρ < 0.05 for any comparison.
 

95% confidence interval of the relative risk between each treated group and the
 

specified control group.
 
APPENDIX F
 

ANALYSES OF THE INCIDENCE OF PRIMARY TUMORS
 

IN MICE FED DAPSONE IN THE DIET
 

91
 

Table Fl. Analyses of the Incidence of Primary Tumors in Male Mice Fed Dapsone

Topography: Morphology
 

Lung: Alveolar/Bronchiolar
 

Adenoma*5
 

 Values0>d
 

Departure from Linear Trende
 

Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

vo 

Weeks to First Observed Tumor
 

Matched
 

Control
 

0/11 (0.00)
 

N.S.
 

 = 0.041
 

—
 

Pooled
 

Control
 

0/31 (0.00)
 

N.S.
 

 = 0.009
 

—
 

Low
 

Dose
 

5/33 (0.15)
 

 = 0.031**
 

Infinite
 

0.464
 

Infinite
 

Infinite
 

1.206
 

Infinite
 

59
 

 in the Diet a 

High
 

Dose
 

1/32 (0.03)
 

N.S.
 

Infinite
 

0.020
 

Infinite
 

Infinite
 

0.052
 

Infinite
 

107
 
Table Fl. Analyses of the Incidence of Primary
 

(continued)
 

Matched
 

Topography: Morphology Control
 

Liver: Hepatocellular
 

Adenoma 0/11 (0.00)
 

 Values0>d N.S.
 

Departure from Linear Trende - 0.050
 

f
 Relative Risk (Matched Control)
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 ——
 

Pituitary: Chromophobe
 

Adenoma 0/7 (0.00)
 

 Values0>d N.S.
 

f
 Relative Risk (Matched Control)
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Tumors in Male
 

Pooled
 

Control
 

3/29 (0.10)
 

N.S.
 

0/18 (0.00)
 

N.S.
 

Mice Fed Dapsone
 

Low
 

Dose
 

6/33 (0.18)
 

N.S.
 

Infinite
 

0.589
 

Infinite
 

1.758
 

0.417
 

10.005
 

89
 

0/28 (0.00)
 

N.S.
 

—
 —
 

in the Dieta
 

High
 

Dose
 

2/31 (0.06)
 

N.S.
 

Infinite
 

0.115
 

Infinite
 

0.624
 

0.055
 

5.058
 

107
 

1/16 (0.06)
 

N.S.
 

Infinite
 

0.026
 

Infinite
 

Infinite
 

0.062
 

Infinite
 

85
 
Table Fl. Analyses of the Incidence of Primary Tumors in Male Mice Fed Dapsone in the Dieta
 

(continued)
 

a

Treated groups received doses of 500 or 1,000 ppm.
 

^Number of tumor-bearing animals/number of animals examined at site (proportion).
 

c

Beneath the incidence of tumors in a control group is the probability level for the Cochran-


Armitage test when Ρ < 0,05; otherwise, not significant (N.S.) is indicated. Beneath the incidence of tumors in a treated group is the probability level for the Fisher exact test for the
 

comparison of that treated group with the matched-control group (*) or with the pooled-


control group (**) when Ρ < 0.05 for either control group; otherwise, not significant
 

(N.S.) is indicated.
 

^A negative trend (N) indicates a lower incidence in a treated group than in a control group.
 

e

The probability level for departure from linear trend is given when Ρ < 0.05 for any comparison.
 

95% confidence interval of the relative risk between each treated group and the
 

specified control group.
 
Table F2. Analyses of the Incidence of Primary Tumors in Female Mice Fed Dapsone in the Dieta
 

Topography: Morphology 

Matched 

Control 

Subcutaneous Tissue: 

Fibrosarcoma 1/13 (0.08) 

 Values0'd N.S. 

Relative Risk (Matched Control)f 

Lower Limit 

Upper Limit 

Relative Risk (Pooled Control)f 

Lower Limit 

Upper Limit 

Weeks to First Observed Tumor 96 

Hematopoietic System: 

Malignant Lymphoma 1/13 (0.08) 

 Values0 > d N.S. 

Relative Risk (Matched Control)^ 

Lower Limit 

Upper Limit 

Relative Risk (Pooled Control)f 

Lower Limit 

Upper Limit 

Weeks to First Observed Tumor 107 

Pooled
 

Control
 

1/36 (0.03)
 

N.S.
 

2/36 (0.06)
 

N.S.
 

Low
 

Dose
 

1/31 (0.03)
 

N.S.
 

0.419
 

0.006
 

31.891
 

1.161
 

0.015
 

88.229
 

94
 

1/31 (0.03)
 

N.S.
 

0.419
 

0.006
 

31.891
 

0.581
 

0.010
 

10.576
 

94
 

High
 

Dose
 

0/35 (0.00)
 

N.S.
 

0.000
 

0.000
 

6.893
 

0.000
 

0.000
 

19.040
 

1/35 (0.03)
 

N.S.
 

0.371
 

0.005
 

28.358
 

0.514
 

0.009
 

9.418
 

108
 
υ. Table F2. Analyses of the Incidence of Primary Tumors in Female Mice Fed Dapsone in the Dieta
 

CO
 

 (continued)
 

I Matched Pooled Low High
 

I Topography: Morphology Control Control Dose Dose
 H
 

TO
 

3 Hematopoietic System: Lymphoma
 

I or Leukemiab

 2/13(0.15) 3/36(0.08) 1/31 (0.03) 1/35 (0.03)
 

ο
 

π
 

ι 

d N.S. N.S.
 f? Ρ Valuesc

> N.S. N.S.
 o
 

\ Relative Risk (Matched Control)r 0.210 0.186
 

S Lower Limit 0.004 0.003
 

§ Upper Limit 3.760 3.348
 u>
 

u>
 

0.387 0.343
 Relative Risk (Pooled Control)f
 

0.008 0.007
 Lower Limit
 

4.516 4.024
 Upper Limit
 

^ Weeks to First Observed Tumor 103 — 94 108
 

a

Treated groups received doses of 500 or 1,000 ppm.
 

^Number of tumor-bearing animals/number of animals examined at site (proportion).
 

c

Beneath the incidence of tumors in a control group is the probability level for the Cochran-


Armitage test when Ρ < 0.05; otherwise, not significant (N.S.) is indicated. Beneath the incidence of tumors in a treated group is the probability level for the Fisher exact test for the
 

comparison of that treated group with the matched-control group (*) or with the pooled-


control group (**) whe Ρ < 0.05 for either control group; otherwise, not significant
 

(N.S.) is indicated.
 

^A negative trend (N) indicates a lower incidence in a treated group than in a control group*
 

e

The probability level for departure from linear trend is given when Ρ < 0.05 for any comparison.
 

95% confidence interval of the relative risk between each treated group and the
 

specified control group.
 


DHEW Publication No. (NIH) 77-820