04 April 2000

               PROFESSIONAL SERVICES and CONFIDENTIALITY AGREEMENT
                                     between
                                   Lexon, Inc.
                                        &
                          DIAGNOSTIC ONCOLOGY CRO, Inc.




                                     PARTIES

The parties to this  Professional  Services and  Confidentiality  Agreement  are
Lexon, Inc., a Delaware  corporation,  and its affiliates,  subsidiaries and the
like  ("LEXON") with  headquarters  located in Tulsa,  Oklahoma,  and DIAGNOSTIC
ONCOLOGY  CRO,  Inc.  ("DOCRO"),  a Delaware  corporation,  located in  Seymour,
Connecticut.



                                    PURPOSES

LEXON  is  engaged  in the  business  of  commercializing  medical  devices,  in
particular,  reagents and in vitro diagnostic  assays such as the assays for the
EbafTM tumor marker used as an aid in the detection of colorectal cancer.

DOCRO is engaged in providing professional services to manufacturers of in vitro
diagnostic medical device manufacturers,  in particular,  providing tactical and
strategic  clinical  trial  services  in support  of  efforts to obtain  federal
regulatory approval for medical devices.

LEXON  desires to have DOCRO  assist  with the review and  analysis  of existing
technical  and clinical  data related to the EbafTM tumor marker assays in order
for DOCRO to provide  LEXON  with  written  executive  summary of a plan to gain
clearance/approval  from the  United  States  Food and  Drug  Administration  to
commercialize an ebaf tumor marker immunoassay, and DOCRO is willing to do so.

In consideration of the mutual promises specified below, DOCRO offers to provide
professional  services to LEXON in accordance  with the terms and  conditions of
this Agreement, which LEXON accepts.


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                                   DEFINITIONS


"Confidential & Proprietary  Information" shall include any information owned by
LEXON.

"DOCRO" shall mean the entity  identified in the PARTIES section,  including any
entities  affiliated  with DOCRO,  (or any  purchaser  of  substantially  all of
DOCRO's  assets),  including  but not  limited  to  DOCRO's  employees,  agents,
officers or principals, and, its contractors.

"FDA"  shall  mean the  United  States  Food and Drug  Administration,  or other
foreign  or  domestic   judicial,   governmental  or  regulatory  bodies  having
jurisdiction  over  matters for which  DOCRO is  providing  services  under this
Agreement.

"LEXON" shall mean the entity  identified in the PARTIES section,  including any
entities affiliated with LEXON (or any purchaser of substantially all of LEXON's
assets),  including but not limited to LEXON's  employees,  agents,  officers or
principals, and, its contractors.



                              TERMS AND CONDITIONS

1.0 Services to be Provided by DOCRO

1.1.  Review of Technical  and Clinical  Data Related to the EbafTM Tumor Marker
Assays - DOCRO shall provide to LEXON assistance with the review and analysis of
existing technical and clinical data related to the EbafTM tumor marker assys in
order for DOCRO to provide LEXON with a written  executive  summary of a plan to
gain  clearance/approval  from the United States Food and Drug Administration to
commercialize an EbafTM tumor marker immunoassay.

1.2. The parties agree that DOCRO shall  provide  LEXON with its services  under
this  Agreement on a  non-exculsive  basis.  Subject to the  limitations of this
Agreement,  DOCRO and LEXON may  provide  or obtain  professional  and  advisory
services to or from any third party.

1.3.  Pursuant  to the  terms  of this  Agreement,  DOCRO  shall  commence  work
immediately upon receipt of a fully executed  original of this Agreement and any
initial moneys set forth herein.


2.0 Term

2.1.  The terms of this  Agreement  shall  commence on 04 April 2000,  and shall
expire on 05 June 2000,  but may be  terminated  at will by either  party giving
thirty (30) days written notice to the other. In the event of such  termination,
LEXOn's sole obligation to DOCRO shall be to pay DOCRO any fees and expenses for
services  either  (i)  rendered  by the  date of  termination  or (ii) at  least
partially  rendered  and  committed  by  DOCRO,  such  fees and  expenses  to be
subtracted  from the  advance  payment  made by LEXON  pursuant  to Section  3.3
hereof.



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2.2.  This  termination  provision  shall not apply to the Section 3.0.  through
14.0., which shall survive in perpetuity.


3.0 Compensation & Reimbursement

3.1.  DOCRO  shall  be  compensation  by  LEXON  at a  rate  of  three  hundred,
twenty-five dollars (US$ 325.00) per hour for professional  services rendered by
DOCRO's President and Chief Executive Officer,  Thomas F. Soriano,  DOCRO's Vice
President of  Biostatistics  and Clinical  Affairs,  Rober P. Thiel,  Ph.D.,  or
DOCRO's Vice President of Laboratory Operations, Steven P. Piccoli, Ph.D., under
the provisions of this Agreement and this Section 3.0.

3.2. DOCRO shall bill LEXON monthly for services  rendered and expenses incurred
under this  Agreement.  LEXON shall  reimburse  DOCRO for services  rendered and
expenses  incurred  under the provision of this  Agreement on a net fifteen (15)
day basis,  time commencing from submission to LEXON of invoice and statement of
work completed or expenses incurred.  If timely payment for invoiced fees is not
made,  in  addition to other  remedies,  DOCRO may impose and LEXON shall pay, a
late  payment  charge equal to one and  one-half  percent  (1.5%) of the overdue
amount each month.

3.3. DOCRO and LEXON will agree to an estimated  maximum limit to fees (Fee Cap)
of two thousand, six hundred dollars (US $ 2,600.00) based upon an estimate of a
total of  eight  (8)  billable  hours  required  for the  professional  services
described  herein to be  rendered  by  DOCRO's  President  and  Chief  Executive
Officer, Thomas F. Soriano, DOCRO's Vice President of Biostatistics and Clinical
Affairs,  Dr. Robert P. Thiel,  Ph.D.,  or DOCRO's Vice  President of Laboratory
Operations,  Steve P. Piccoli,  Ph.D. If in the  performance of its  obligations
described  herein DOCRO shall exceed the Fee Cap,  DOCRO shall  provide  LEXON a
written  Project  Extension  Authorization  (PEA)  describing the new aspects or
tasks  required to complete the project.  The Fee Cap shall not include any fees
or expenses  applicable  to  meetings  with LEXON or its  partners,  or fees for
follow-up or additional data requests from LEXON or any affiliate of LEXON. Fees
and  expenses  for  follow-up  or  additional  data  requests  from LEXON or any
affiliate  of LEXON  shall be billed to LEXON  according  to Section 3.0 of this
Agreement.

3.4.  DOCRO shall not  initiate  any work the cost of which shall exceed the Fee
Cap prior to obtaining  LEXON's written  approval of a PEA. A PEA shall describe
the aspects of the project to be performed by DOCRO,  including a description of
the specific  personnel and other  resources  needed to perform the new tasks of
the project,  the time or schedule needed to complete such tasks, and a proposed
schedule  for project  related  payments.  The Fee Cap shall be increased by the
amount of any approved PEA.

3.5.  DOCRO  shall  ensure  that all charges  are  allocated  accurately  to the
activity or project for which such charges were  incurred,  and are supported by
documents.  The nature and purpose of all invoice  items shall be  identified in
the supporting documents.


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3.6. DOCRO shall be paid for reasonable and necessary business expenses that are
incurred by DOCRO in the course of performing the  obligations of this Agreement
as described  in this  Agreement.  Such costs may include,  (but are not limited
to), the  following:  computer  research;  laboratory  expenses;  legal expenses
related to  obtaining  opinions  or any other  request by LEXON;  long  distance
telephone and telefacsimile charges;  postage, printing and courier charges; and
travel  expenses,  (including  the cost of  transportation,  meals and lodging).
LEXON shall  compensate DOCRO fully for all travel and living expenses which are
agreed to in advance in writing by LEXON and are incurred for site visits to the
premises of LEXON, any clinical investigator,  any laboratory  investigator,  or
any other  location  that may be requested or are required in order for DOCRO to
fulfill its obligations described in this Agreement.


4.0 Confidential & Proprietary Information

4.1.  DOCRO and LEXON hereby agree with respect to  Confidential  &  Proprietary
Information:   (1)  DOCRO  agrees  to  maintain  the   confidentiality   of  any
Confidential & Proprietary  Information disclosed by LEXON; (2) DOCRO agrees not
to make any disclosure of LEXON's Confidential & Proprietary  Information to any
third party; (3) DOCRO agrees not to use Confidential & Proprietary  Information
except for the purpose  contemplated in this Agreement,  unless such further use
is  specifically  authorized  in writing by LEXON;  (4) DOCRO  agrees to protect
LEXON's  Confidential  & Proprietary  Information  whether in storage or in use,
with the same degree of care as is exercised  to protect its own against  public
disclosure (but in no case with any less degree than reasonable  care);  and (5)
DOCRO agrees not to disclosure LEXON's Confidential & Proprietary Information to
any  personnel  other than those for whom such  knowledge is  essential  for the
purposes  contemplated in this  Agreement,  and such disclosure to them shall be
made only under conditions of strict confidentiality.

4.2.  The  obligations  in this  Article  shall  not  apply  to  Confidential  &
Proprietary   Information   that   DOCRO   can  show  by   previously   existing
documentation:  (a) is in the public domain on the date of this  Agreement;  (b)
comes into the public domain other than through DOCRO's fault or negligence; (c)
is lawfully obtained from a third party with full rights of disclosure;  (d) was
already  known to DOCRO at the date of receipt of the  information  pursuant  to
this Agreement;  or (e) becomes known  independently to DOCRO without making use
of any of LEXON's Confidential & Proprietary information.

4.3.  If this  Agreement  expires  or is  terminated,  then DOCRO  shall  return
promptly all  Confidential & Proprietary  Information,  together with all copies
thereof,  except for the  retention  of one copy for archival  purposes.  Upon a
written  request,  DOCRO shall provide an accounting for the  disposition of all
such  documents or  specimens,  including a written  certification  attesting to
return of all such  confidential  information.  DOCRO  shall  return  such items
regardless of ny claims against LEXON.

4.4.  No party  shall  make any  press  release  or  other  public  announcement
concerning the existence,  terms,  or execution of this Agreement  without prior
written consent of the other party.


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<PAGE>


4.5. If a disclosure of  Confidential  & Proprietary  Information  prohibited by
this  Agreement is required  specifically  by law or by court order,  DOCRO will
notify LEXON of such required disclosure and, if so requested, will executed all
necessary  documents and provide all reasonable  assistance  necessary to defend
LEXON's  lawful  right to  prevent  or limit  such  disclosure.  DOCRO  shall be
entitled to reasonable compensation for assisting in such a defense.


5.0  Warranties & Certifications

5.1.  DOCRO  warrants  that  is  aware  of the  obligations  imposed  under  FDA
regulations  and  guidelines  and  other  governmental  laws,   regulations  and
guidelines  which pertain to work DOCRO may perform under this Agreement.  DOCRO
warrants  that it will  conduct  all work in full  compliance  with  such  laws,
regulations and guidelines.

5.2.  DOCRO  certifies  that  neither  the  company,  its  affiliates,   agents,
contractors nor any of its employees are subject to disbarment under the Generic
Drug  Enforcement  act,  or have been  disqualified,  prohibited,  suspended  or
otherwise  restric6ted by the FDA or other  governmental  agency from performing
its obligations under this Agreement.

5.3. DOCRO certifies that all of its employees, agents and contractors are bound
by the provisions of this  Agreement,  that it has obtained  written  agreements
from such employees and agents that are consistent with the provision of Section
4.0 of  this  Agreement,  and  that  it  will  obtain  written  agreements  from
employees,  agents and contractors who in the future will become associated with
the project contemplated in this Agreement.

5.4. DOCRO  represents and certifies to LEXON and that it is not restricted from
performing  its  obligations  under this  Agreement by its  obligations to other
parties.  DOCRO  further  represents  and  certifies  that it will inform  LEXON
immediately  of any  circumstance  that might impair the ability of the DOCRO to
perform its obligations, including any actions that might result in FDA or other
government agency action against DOCRO.

5.5.  LEXON  warrants  that it is aware of the  obligations  imposed  under  FDA
regulations  and  guidelines  and  other  governmental  laws,   regulations  and
guildlines  which pertain to work DOCRO may perform under this Agreement.  LEXON
warrants that it will support DOCRO in  conducting  all work in full  compliance
with such laws, regualtipons and guildelines.

5.6. LEXON certifies that all of its employees, agents and contractors are bound
by the provisions of this  Agreement,  that it has obtained  written  agreements
from such  employees  and agents  that are  consistent  with the  provisions  of
Section 4.0 of this Agreement,  and that it will obtain written  agreements from
employees,  agents and contractors who in the future will become associated with
the project contemplated in this Agreement.

5.7.  LEXON  and  DOCRO  warrant  that the  signatories  to this  Agreement  are
authorized to execute this Agreement on behalf of the respective parties.



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6.0 Modification of Agreement

6.1. No waiver or modification of this Agreement shall be valid, nor shall it be
offered or received in evidence in any  proceeding,  arbitration  or  litigation
between the parties  arising  out of or related to this  Agreement,  unless such
waiver or modification is in writing signed by authorized representative of both
parties,  particularly  pointing out any  provisions  to be added,  deleted,  or
modified.

6.2. Unless  expressly  approved by the waiving party in accordance with Section
6.1.,  the failure of either party to enforce any  provision  of this  Agreement
shall not be  construed  as a waiver or  limitation  of that  party's  rights to
subsequently  enforce and compel strict  compliance  with every provision of the
Agreement.  No waiver (express or implied) by either party of any breach of this
Agreement shall constitute a waiver of any other or subsequent breach.


7.0 Assignment

     This Agreement  shall be binding on and inure to the benefit of each party,
its successors or assigns.


8.0 Independent Contractor Status

8.1.  The  business  relationship  between  DOCRO  and  LEXON  shall  be that of
independent contractors,  and does not constitute a partnership,  joint venture,
agency or contract of employment.

8.2. No party shall have the authority to make any  statements,  representations
or  commitments  of any kind, or to take any action that shall be binding on the
other,  except as provided for herein or authorized in writing by the parties to
be bound.

8.3.  DOCRO solely shall be responsible  for provision of personnel,  equipment,
and  supplies,  and,  subject  to the terms of this  Agreement,  for  payment of
DOCRO's costs, suppliers,  employees and contractors. In no case shall any party
have the authority,  or represent  themselves as having the  authority,  to bind
legally any other in contract, debt or otherwise.


9.0 Use of Third Party Service Providers

     DOCRO will obtain prior written approval from LEXON of any third party that
DOCRO intends to use for any professional services provided to LEXON. LEXON on a
reasonable basis may reject the use of any such external DOCRO, affiliate, agent
or subcontractor.



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10.0 Notice

10.1. Any notice  required under this Agreement  shall be deemed given only upon
receipt of any letter of  instrument  sent by  certified  mail,  return  receipt
requested,  postage prepaid by the sender,  by overnight  courier or by personal
delivery,  unless prior notice is tenured by the sender that a signed  telefaxed
response  followed  by  confirmation  by mail  will  satisfy  the  terms of this
provision.

If to DOCRO:                                   If to LEXON:
------------                                   ------------
Thomas F. Soriano                              Thomas R. Coughlin, Jr.
President and Chief Executive Officer          Medical Director
DIAGNOSTIC ONCOLOGY CRO, Inc.                  Lexon, Inc.
73 Cogwheel Lane                               8908 South Yale Avenue, Suite 409
Seymour, CT 06483                              Tulsa, OK 74137

10.2.  From  time to time  either  party,  by  written  notice  to the  other in
accordance  with this Section  11.0,  may  designate  different  or  alternative
addresses or manners of delivery that shall become the effective or  alternative
addresses, or manner of delivery, for such party or project as so designated.


11.0     Entire Understanding

       This Agreement  contains the complete  understanding  between the parties
and shall,  as of the date of execution of this  Agreement,  supersede all other
written or oral agreements  between the parties concerning the subject matter of
this Agreement.


12.0     Severability

       The terms of this Agreement are severable.  If any term of this agreement
is held invalid or unenforceable, the valid and enforceable portion of such term
and the  remaining  provisions of this  Agreement  will remain in full force and
effect. The remaining contract shall be interpreted consistently with the intent
of the  parties  with  respect to the entire  Agreement  when the  contract  was
executed.


13.0     Dispute Resolution

13.1.  DOCRO and LEXON agree that a breach or threat of breach of any obligation
described under Section 4.0 necessarily  will result in immediate,  material and
irreparable damages to the other. Thus, each party agrees that the appearance or
threat of breach of Section 4.0 shall  entitle a party to obtain,  without bond,
injunctive or equitable relief in any court of competent jurisdiction to enforce
compliance with a party'  obligations  under that Section.  Seeking or obtaining
such relief shall not  prohibit or limit other  remedies to which a party may be
entitled.



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13.2. Except when seeking  injunctive relief for the breach of obligations under
Section 4.0 any claims  brought by the parties on mattes  relating to or arising
out  this  Agreement  shall be  first  submitted  to  binding  arbitration.  The
arbitration shall be conducted in the State of Connecticut,  in conformance with
the rules of the American Arbitration Association,  or, if mutually agreed to by
the parties, other rules of arbitration. Arbitration shall be conducted by three
arbitrators.  Each party  shall  appoint one  arbitrator  and the third shall be
appointed jointly by parties' appointed arbitrators.

13.3. The confidentiality  provisions of this Agreement shall not be enforceable
with respect ot affecting a dispute resolution proceeding between the parties.

13.4.  The  parties  agree  that they will use their  best  efforts  to  resolve
amicably  any  dispute  arising  out  of or  relating  to  this  Agreement.  Any
controversy,  claim or dispute  that cannot be so  resolved  shall be settled by
final  binding  arbitration  in  accordance  with  the  rules  of  the  American
Arbitration  Association and judgement upon the award rendered by the arbitrator
or arbitrators may be entered in any court having jurisdiction thereof. Any such
arbitration  shall be  conducted in  Connecticut,  or such other place as may be
agreed  upon  mutually  by  the  parties.  Within  on  e  (1)  month  after  the
commencement  of the  arbitration,  each party shall select one person to act as
arbitrator,  and the two arbitrators so selected shall select a third arbitrator
within on (1)  month of their  appointment.  The  Arbitration  Period  shall not
exceed three (3) months. Each party shall bear its own costs and expenses and an
equal share of the arbitrator's expenses and administrative fees of arbitration.

13.5.  With respect to all other  provisions of this  Agreement,  this Agreement
shall be governed by and  construed in  accordance  with the law of the State of
Connecticut,  without  consideration  of choice of law. Any claims of actions by
either party related to all provisions other than the confidentiality provisions
of Section 4.0 shall be brought  before any court of competent  jurisdiction  in
the State of Connecticut.


14.0     Headings

       The headings  contained in this Agreement are only for the convenience of
the parties and are not to be construed as a substantive  provision and will not
in any manner affect the interpretation of this Agreement.




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The parties execute this Agreement in accordance with all of the above terms and
conditions.


For Lexon ,Inc.:

By: /s/ THOMAS R. COUGHLIN                  Date: April 7, 2000
    ------------------------------                ----------------------
      Thomas R. Coughlin, Jr.
      Medical Director



For DIAGNOSTIC ONCOLOGY CRO, Inc.:

By: /s/ THOMAS F. SORIANO                   Date: Tuesday, 04 April 2000
    ------------------------------                ----------------------
      Thomas F. Soriano
      President and Chief Executive Officer


<PAGE>
DIAGNOSTIC ONCOLOGY CRO, Inc.                73 Cogwheel Lane - Syemour CT 06483
Specialists in Oncology                Voice (203) 881-1032 - Fax (203) 881-1192
in Vitro Diagnostics                                   Page 01 of 02

                                                Tuesday, 18 April 2000

Thomas R. Coughlin, Jr. M.D.                 VIA FEDERAL EXPRESS
Medical Director
Lexon, Inc.                                  e-mail: thomas.coughlinjr@gte.net
8908 S. Yale Avenue, Suite 409               Telephone: 918-492-4125
Tulsa, OK 74137-3545                         Telefacsimile: 918-492-2560

                                  CONFIDENTIAL

RE:  FOR EXECUTION - Project  Extension  Authorization to Existing  Professional
     Services and  Confidentiality  Agreement  (Effective  Date:  04 April 2000;
     Expiration  Date: 05 June 2000) - Extends  DOCRO's  Agreement an Additional
     100 Billable Hours to 18 April 2001

Dear Thomas:

     I am pleased that Lexon, Inc.: ("LEXON") has decided to expand the scope of
LEXON's current Professional Servies and Confidentiality Agreement ("PSCA") with
Diagnostic Oncology CRO, Inc. ("DOCRO").

     According to the terms of our current PSCA (Effective  Date: 04 April 2000;
Expiration  Date:  05 June  2000)  LEXON  and  DOCRO  now  enter  into a Project
Extension  Authorization  ("PEA")  which  expires  on 18  April  2001.  This PEA
authorized  DOCRO to  provide to LEXON up to an  additional  one  hundred  (100)
billable hours of professional  services related to LEXON's  business  interests
form today  through  18 April  2001.  DOCRO  shall bill LEXON at a rate of three
hundred,  twenty-five dollars (US $325.00) per hour for services rendered. LEXON
and DOCRO agree to a Fee Cap of thirty-two  thousand,  five hundred  dollard (US
$32,500.00) for this PEA.

     Any billable hours described herein and any additional expenses incurred by
DOCRO (as  described  in Section  3.0 of the PSCA) shall be billed to LEXON on a
net fifteen (15) day basis  according to the terms of the PSCA.  All other terms
and conditions of the PSCA shall continue to apply to this PEA.

     Please  indicate   LEXON's   accedptance  of  the  terms  of  this  PEA  by
countersigning in the place below both originals of this PEA. You may retain one
original  for LEXON's  records and return the other  original to my attention at
the address shown above.

                                    Best regards,

                                           Thomas F. Soriano
                                           President and Chief Executive Officer


Accepted by: /s/ THOMAS COUGHLIN JR.                Date: April 20, 2000
            -------------------------                     ---------------
            Signature
            Thomas R. Coughlin, Jr. M.D. - Medical Director, Lexon, Inc.