Studies indicate that mutations in tumor suppressor genes occur early in the process of carcinogenesis, and that these mutations are correlated with a subsequent development of cancer. The detection of such alterations would provide useful molecular markers for diagnosis, surveillance, early tumor identification and intervention, and prognosis. A novel human gene, designated as “Zsig62,” resides within a region of chromosome 16q that is associated with prostate and breast cancer, and that appears to contain tumor suppressor genes. Like a tumor suppressor gene, the Zsig62 gene is expressed in particular normal tissues, but not in tumors derived from those tissues.

EXAMPLE 1 
 Expression of the Zsig62 Gene A probe for northern analyses was produced using ZC18,137 (5′ CTG ATG CAG CAC TCA AGA CAA TC 3′; SEQ ID NO:4) and ZC18,139 (5′ GGC ATT TGT GGG CAG TGT TGG GGC 3′; SEQ ID NO:5) as primers and a clone encoding Zsig62 as template. The probe was a radioactively labeled using a commercially available random priming kit (REDIPRIMEII kit; AMERSHAM PHARMACIA BIOTECH, Inc.; Piscataway, N.J.), following the manufacturer's protocol. The probe was purified using a NUCTRAP push column (STRATAGENE, La Jolla, Calif.). EXPRESSHYB (CLONTECH Laboratories, Inc.; Palo Alto, Calif.) solution was used for the prehybridization and hybridization solutions for the northern blots. Hybridization took place overnight at 65° C. Following hybridization, the blots were washed in 2× SSC, 0.1% SDS at 25° C. for one hour, followed by a wash in 0.1× SSC and 0.1% SDS at 50° C. for one hour. Blots were exposed to film at −80° C. for several days. The results demonstrated that the Zsig62 gene is expressed in tissue from placenta, spinal cord, total pituitary, prostate, as well as prostate cell lines representing epithelial cells, smooth muscle cells, and stromal muscle cells. In contrast, little or no Zsig62 gene expression was observed in samples obtained from adult brain, fetal brain, heart, kidney, liver, fetal lung, pancreas, skeletal muscle, spleen, testis, thymus, small intestine, colon, peripheral blood lymphocytes, esophageal tumor, normal esophagus, stomach tumor, normal stomach, lung tumor, and the Y-1A adrenal cell line. In a number of instances, differential Zsig62 gene expression was observed in normal and cancerous tissues. Specifically, Zsig62 RNA was detected in tissue from lung, uterus, breast, fallopian tube, ovary, and gall bladder, while little or no Zsig62 gene expression in tumors derived from these organs. 
 EXAMPLE 2 
 Chromosomal Localization of the Zsig62 Gene Zsig62 was mapped to chromosome 16 using the commercially available “GeneBridge 4 Radiation Hybrid Panel” (Research Genetics, Inc., Huntsville, Ala.). The GeneBridge 4 Radiation Hybrid Panel contains amplifiable DNA molecules from each of 93 radiation hybrid clones, plus two control DNA molecules (the HFL donor and the A23 recipient). A WWW server (http://www-genome.wi.mit.edu/cgi-bin/contig/rhmapper.pl) allows mapping relative to the Whitehead Institute/MIT Center for Genome Research's radiation hybrid map of the human genome (the “WICGR” radiation hybrid map) which was constructed with the GeneBridge 4 Radiation Hybrid Panel. For the mapping of Zsig62 with the “GeneBridge 4 RH Panel,” 20 &mgr;l reactions were set up in a 96-well microtiter plate (STRATAGENE, La Jolla, Calif.) and used in a “RoboCycler Gradient 96” thermal cycler (STRATAGENE). Each of the 95 PCR reactions consisted of: 2 &mgr;l 10× KlenTaq PCR reaction buffer (CLONTECH Laboratories, Inc., Palo Alto, Calif.), 1.6 &mgr;l dNTPs mix (2.5 mM each, PERKIN-ELMER, Foster City, Calif.), 1 &mgr;l sense primer, ZC 19,942 (5′ GGA GCT GGC ATC TTC TGA 3′; SEQ ID NO:6), 1 &mgr;l antisense primer, ZC 19,943 (5′ TCC CCA CCC ACC CAC TAT 3′; SEQ ID NO:7), 2 &mgr;l “RediLoad” (Research Genetics, Inc., Huntsville, Ala.), 0.4 &mgr;l 50× Advantage KlenTaq Polymerase Mix (Clontech Laboratories, Inc.), 25 ng of DNA from an individual hybrid clone or control and ddH2O for a total volume of 20 &mgr;l. The reactions were overlaid with an equal amount of mineral oil and sealed. The PCR cycler conditions were as follows: an initial 1 cycle 5 minute denaturation at 95° C., 40 cycles of a 1 minute denaturation at 95° C., 1 minute annealing at 64° C. and 1.5 minute extension at 72° C., followed by a final 1 cycle extension of 7 minutes at 72° C. The reactions were separated by electrophoresis on a 2% agarose gel (Life Technologies, Inc., Gaithersburg, Md.). The results showed that Zsig62 maps 0.60 cR — 3000 from the framework marker CHLC.GATA86C08 on the chromosome 16 WICGR radiation hybrid map. O Proximal and distal framework markers were CHLC.GATA86C08 and D16S520, respectively. The use of surrounding markers positions Zsig62 in the 16q24.3 region on the integrated LDB chromosome 16 map (The Genetic Location Database, University of Southhampton, WWW server: http://cedar.genetics. soton.ac.uk/public_html/). From the foregoing, it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims.