<PAGE>

                                                                   Exhibit 10.12

                                LICENSE AGREEMENT

         THIS LICENSE AGREEMENT (the "Agreement") effective as of March 25, 1999
(the "Effective Date") is by and between Genzyme Corporation, a Massachusetts
corporation having its principal offices at One Kendall Square, Cambridge, MA
02139 ("Genzyme"), through Genzyme's Molecular Oncology Division, and EXACT
Laboratories, Inc., a Delaware corporation having its principal offices at 63
Great Road, Maynard, MA 01754 ("EXACT").

                                   WITNESSETH:

         WHEREAS, Genzyme is the licensee of certain patent rights relating to
the Field (as defined herein) under the JHU License Agreement (as defined
herein) and is willing to grant to EXACT a worldwide, nonexclusive,
royalty-bearing sublicense to use such patent rights for the development and
commercialization of Diagnostic Services, Licensed Reagents and Kits (each as
defined herein) in the Field upon the terms and conditions set forth herein; and

         WHEREAS, EXACT desires to obtain a worldwide, nonexclusive,
royalty-bearing sublicense to use such patent rights for the development and
commercialization of Diagnostic Services, Licensed Reagents and Kits in the
Field on the terms and conditions set forth herein; and

         WHEREAS, Genzyme is willing to grant EXACT such a sublicense on the
terms and conditions set forth herein in light of the relationship between EXACT
and JHU (as defined herein) and the relationship between Genzyme and JHU;

         NOW THEREFORE, in consideration of the mutual covenants herein
contained and intending to be legally bound hereby, the parties hereto agree as
follows:

                             ARTICLE 1. DEFINITIONS

1.1      "Affiliate" shall mean any corporation or other entity which controls,
         is controlled by, or is under common control with EXACT. A corporation
         or other entity shall be regarded as in control of another corporation
         or entity if it owns or directly or indirectly controls more than fifty
         percent (50%) of the voting stock or other ownership interest of the
         other corporation or entity, or if it possesses, directly or
         indirectly, the power to direct or cause the direction of the
         management and policies of the corporation or other entity or the power
         to elect or appoint more than fifty percent (50%) of the members of the
         governing body of the corporation or other entity.

1.2      "Diagnostic Service(s)" shall mean the performance of laboratory-based
         assays covered in whole or in part by a Valid Claim of the Patent
         Rights.

1.3      "Field" shall mean the determination, in stool or samples prepared from
         stool, of the presence of, absence of or variation(s) within a nucleic
         acid of interest, or differences between a nucleic acid of interest and
         a reference standard or sample, including but not limited to screening,
         diagnosis, prognosis and monitoring tests, for the purpose of detecting
         changes associated with colorectal cancer.

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                                      -2-

1.4      "First Commercial Sale" shall mean (a) the first performance for
         consideration of a Diagnostic Service in the Field or (b) the first
         sale for consideration of a Licensed Reagent or Kit for use in the
         Field, as applicable. Any performance of a Diagnostic Service or
         transfer of Licensed Reagents or Kits by EXACT solely for purposes of
         performing Research shall not be deemed to constitute a First
         Commercial Sale.

1.5      "Gene Patent Rights" shall mean the United States and foreign patents
         and patent applications relating to the APC gene and/or the p53 gene
         and licensed (with the right to grant sublicenses) to Genzyme pursuant
         to the JHU License Agreement together with patents arising therefrom
         and any extensions, registrations, confirmations, reissues, divisions,
         continuations or continuations-in-part, re-examinations or renewals
         thereof, including without limitation the patents and patent
         applications listed in Appendix A hereto (which may be updated from
         time to time to include such additional patents and patent application
         that may arise therefrom); PROVIDED, HOWEVER, that Gene Patent Rights
         expressly excludes any claims of such patents and patent applications
         that fall outside of the Field, including, without limitation, claims
         to antibodies, to the treatment, prevention or remedying of a gene
         deficiency, to purified proteins, or to DNA sequences other than those
         sequences that correspond to the p53 gene and the APC gene; PROVIDED
         FURTHER that DNA sequences which are (i) immediately adjacent to the
         p53 or APC genes and (ii) necessary to the use of the p53 or APC genes,
         respectively, in the Field shall be considered within the Gene Patent
         Rights.

1.6      "Instrument" shall mean any instrument, apparatus, appliance, automated
         system or computer software that is covered in whole or in part by a
         Valid Claim of the Patent Rights and is useful or necessary for
         performing laboratory-based assays.

1.7      "JHU License Agreement" shall mean the License Agreement dated as of
         February 5, 1992 by and between Genzyme (as successor to PharmaGenics,
         Inc.), The Johns Hopkins University ("JHU") and Hoffman-La Roche Inc.
         ("Roche"), as amended from time to time.

1.8      "Kit" shall mean a collection of one or more Reagents, including at
         least one Licensed Reagent, packaged in the form of a kit.

1.9      "Licensed Reagent" shall mean any Reagent covered in whole or in part
         by a Valid Claim of the Patent Rights.

1.10     "Methodology Patent Rights" shall mean the United States and foreign
         patents and patent applications relating to methods of detecting
         mammalian nucleic acids isolated from stool specimens and reagents
         therefor and licensed (with the right to grant sublicenses) to Genzyme
         pursuant to the JHU License Agreement together with patents resulting
         therefrom and any extensions, registrations, confirmations, reissues,
         divisions, continuations or continuations-in-part, re-examinations or
         renewals thereof, including without limitation the patents and patent
         application listed in Appendix B hereto (which may be updated from time
         to time to include such additional patents and patent applications that
         may arise therefrom).
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                                      -3-

1.11     (a) "Net Sales" shall mean the adjusted gross sales of Licensed
         Reagents and Kits by EXACT LESS [CONFIDENTIAL TREATMENT REQUESTED]/*/
         of adjusted gross sales in lieu of items such as custom duties, inbound
         transportation, insurance costs, agent's commission, bad debts, etc.
         The adjusted gross sales shall mean the actual gross sales price of a
         Licensed Reagent or Kit billed by EXACT (not including miscellaneous
         items on the invoice such as taxes, etc.) LESS chargebacks, cash
         discounts, credits or allowances (not including miscellaneous items
         credited such as taxes, etc.) including those incurred or granted on
         account of price adjustments, rejections, returns, rebates or recalls
         of Licensed Reagents or Kits previously sold. "Net Sales" does not
         include "no charge" samples to the extent customary in the trade.

         (b) In the event that EXACT decides to sell a Kit which combines
         Licensed Reagents with ingredients or components which are not Licensed
         Reagents (such other ingredients or components being "Other Items"),
         then (i) EXACT shall notify Genzyme in writing of its intent to offer
         such combination, (ii) Genzyme and EXACT shall, within thirty (30) days
         after Genzyme's receipt of such notification, initiate good-faith
         negotiations on the value of the Licensed Reagents which shall be used
         as the basis to calculate Net Sales pursuant to this clause (b) and
         (iii) if the parties can not reach agreement within thirty (30) days
         after the commencement of such negotiations, such dispute shall be
         referred to arbitration pursuant to Article 11 hereof. However, in no
         event shall the royalty rates on Net Sales be reduced by more than
         [CONFIDENTIAL TREATMENT REQUESTED]/*/. The term "Other Items" does not
         include solvents, diluents, carriers, excipients, enzymes used in
         amplification for diagnostic use, or the like used in formulating a
         product.

         (c) In the event that a Licensed Reagent or Kit is sold for
         non-monetary consideration in addition to or in lieu of money, the
         value of such consideration to the extent that it can be reasonably
         determined by EXACT shall be added to Net Sales in accordance with
         Sections 1.11 (a) and (b) hereof.

         (d) No deductions shall be made for commissions paid to individuals
         whether they be with independent sales agencies or regularly employed
         by EXACT and on its payroll, or for cost of collections.

         (e) Net Sales expressly excludes transfers or dispositions of Licensed
         Reagents or Kits at cost or less than cost for the sole purpose of
         conducting Research.

1.12     (a) "Net Service Revenues" shall mean actual billings by EXACT for the
         performance of Diagnostic Services less the following deductions to the
         extent that they are applicable and are not already deducted in the
         actual billings: (i) discounts allowed and taken, in amounts customary
         in the trade; (ii) sales and/or use taxes and/or duties imposed upon
         and with specific reference to particular sales.

        (b) If a Diagnostic Service(s) is offered in combination with another
        diagnostic or other service(s) (such as patient counseling) provided by
        EXACT (such other services being referred to as "Other Services" and
        such Diagnostic Service(s) and Other Services collectively being
        referred to as "Combination Services"), Net Service Revenues for

         /*/ [CONFIDENTIAL TREATMENT REQUESTED] INDICATES MATERIAL THAT HAS BEEN
         OMITTED AND FOR WHICH CONFIDENTIAL TREATMENT HAS BEEN REQUESTED. ALL
         SUCH OMITTED MATERIAL HAS BEEN FILED WITH THE SECURITIES AND EXCHANGE
         COMMISSION PURSUANT TO RULE 406 PROMULGATED UNDER THE SECURITIES ACT OF
         1933, AS AMENDED.
<PAGE>
                                      -4-

        purposes of determining royalties on the Diagnostic Service(s) shall be
        calculated as provided below:

                  (i)   If the Diagnostic Service(s) and the Other Services are
                        sold or provided separately, Net Service Revenues shall
                        be calculated by multiplying the Net Service Revenues of
                        the Combination Service (as determined in accordance
                        with Section 1.12(a) above but applied to the
                        Combination Service), by the fraction A/(A+B), where "A"
                        is the invoice price of the Diagnostic Service(s) and
                        "B" is the invoice price of the Other Services in the
                        Combination Service if sold or provided separately.

                  (ii)  If the Diagnostic Service(s) are sold or provided
                        separately but the Other Services are not, Net Service
                        Revenues shall be calculated by multiplying the Net
                        Service Revenues of the Combination Service (as
                        determined in accordance with Section 1.12(a) above but
                        applied to the Combination Service), by the fraction
                        A/C, where "A" is the invoice price of the Diagnostic
                        Service(s) and "C" is the invoice price of the
                        Combination Service.

                  (iii) If the Diagnostic Service(s) and the Other Services in
                        the combination are not sold or provided separately, Net
                        Service Revenues for purpose of determining royalties on
                        the Diagnostic Service(s) shall be calculated by
                        multiplying Net Service Revenues of the Combination
                        Service (as determined in accordance with Section
                        1.12(a) above but applied to the Combination Service) by
                        the fraction E/(E+D), where "E" is the value of the
                        Diagnostic Service(s) and "D" is the reasonably
                        estimated value (using accepted diagnostic industry
                        standards) of the Other Services based at least in part
                        on the value of the other active component or components
                        used in the Combination Service; provided, that (A)
                        EXACT shall notify Genzyme in writing of its intent to
                        offer such Combination Services, (B) Genzyme and EXACT
                        shall, within thirty (30) days after Genzyme's receipt
                        of such notification, initiate good-faith negotiations
                        on the value of the Diagnostic Service(s) and Other
                        Services which shall be used as the basis to calculate
                        Net Service Revenues pursuant to this clause (iii) and
                        (C) if the parties can not reach agreement within thirty
                        (30) days after the commencement of such negotiations,
                        such dispute shall be referred to arbitration pursuant
                        to Article 11 hereof.

         (c) In the event that a Diagnostic Service is provided for non-monetary
         consideration in addition to or in lieu of money, the value of such
         non-monetary consideration to the extent that it can be reasonably
         determined by EXACT shall be added to Net Service Revenues in
         accordance with Sections 1.12(a) and (b) hereof.

         (d) Net Service Revenues expressly excludes the use or performance of
         Diagnostic Services at cost or less than cost for the sole purpose of
         conducting Research.
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                                      -5-

1.13     "Patent Rights" shall mean collectively the Gene Patent Rights and the
         Methodology Patent Rights.

1.14     "Reagents" shall mean reagents useful in or necessary to the
         performance of laboratory-based assays, whether used individually or
         sold or used as one or more component(s) of a kit.

1.15     "Research" shall mean pre-clinical, clinical and regulatory activities
         conducted by or on behalf of EXACT to develop and obtain regulatory
         approvals of products or services utilizing the Patent Rights licensed
         to EXACT hereunder.

1.16     "Valid Claim" shall mean an issued claim of an unexpired patent, or a
         claim of a pending patent application, which shall not have been
         withdrawn, canceled or disclaimed, or held invalid or unenforceable by
         a court of competent jurisdiction in an unappealed or unappealable
         decision. Notwithstanding the foregoing to the contrary, a claim of a
         pending patent application, divisional application, or
         continuation-in-part application, or the foreign equivalents thereof,
         shall cease to be a Valid Claim if no patent has issued on such claim
         on or prior to the fifth (5th) anniversary of the date of filing such
         patent application (or, in the case of a continuation application or
         foreign equivalent thereof, the date of filing of the earliest parent
         application), provided that such claim shall once again become a Valid
         Claim on the issue date of a patent that subsequently issues and
         includes such claim.

                            ARTICLE 2. LICENSE GRANT

2.1      Genzyme hereby grants to EXACT, subject to all the terms and conditions
         of this Agreement, a worldwide, nonexclusive right and license (without
         the right to grant sublicenses) under the Patent Rights to: (a) use,
         offer to sell, sell and practice Diagnostic Services in the Field; (b)
         make, have made, use, offer to sell, sell and import Licensed Reagents
         in the Field; and (c) make, have made, use, offer to sell, sell and
         import Kits in the Field.

2.2      The license granted hereunder shall not extend to Instruments. In the
         event that Genzyme becomes aware of any Instruments, Genzyme shall
         deliver written notice thereof to EXACT. In the event that after the
         Effective Date EXACT decides in good faith to develop Instruments for
         use in the Field and delivers written notice of such decision to
         Genzyme, Genzyme and EXACT shall, within thirty (30) days after
         Genzyme's receipt of such notification from EXACT, enter into good
         faith negotiations for a worldwide, non-exclusive license (without the
         right to grant sublicenses) to be granted by Genzyme to EXACT under the
         Patent Rights to make, use, offer to sell, sell and import Instruments
         in the Field. Any such license shall include commercially reasonable
         terms and conditions. In the event that Genzyme and EXACT are unable to
         reach agreement on the terms of any such license within ninety (90)
         days after the date Genzyme and EXACT commence negotiations for such
         license, then the dispute shall be immediately referred to one (1)
         executive officer of each party, chosen at the sole discretion of that
         party, who shall negotiate in good faith with each other to resolve the
         dispute during the period ending thirty (30) days after the date of
         such referral. If the designated officers of the parties are
<PAGE>
                                      -6-

         unable to resolve the dispute within such thirty (30) day period, the
         dispute shall be referred to arbitration pursuant to Article 11 hereof.

                            ARTICLE 3. DUE DILIGENCE

3.1      EXACT agrees to use commercially reasonable efforts to make (i)
         Diagnostic Services,(ii) Licensed Reagents and (iii) Kits available for
         the benefit of the general public consistent with regulatory compliance
         and public safety.

3.2      EXACT's material failure to perform in accordance with any subsection
         of Section 3.1 above shall be grounds for Genzyme to terminate the
         license under Section 2.1. above with respect to Diagnostic Services,
         Licensed Reagents or Kits, as applicable, pursuant to Section 7.8
         hereof by delivering written notice of its intention to terminate to
         EXACT. If EXACT disputes Genzyme's determination, (i) EXACT shall
         deliver written notice of such dispute within ten (10) business days
         after its receipt of notice from Genzyme of its intent to terminate,
         (ii) the matter shall be referred to arbitration pursuant to Article
         11hereof and (iii) EXACT's license under Section 2.1 above to the
         Diagnostic Services, Licensed Reagents or Kits, as applicable, and
         EXACT's obligations with respect thereto shall continue in full force
         and effect until the resolution of such arbitration.

3.3      Within thirty (30) days after the date this Agreement is signed on
         behalf of EXACT and subsequently no later than May 1 and November 1 of
         each year, commencing on November 1, 1999, EXACT shall provide a
         written report to Genzyme on its research, development and
         commercialization efforts with respect to (i) Diagnostic Services,
         (ii)Licensed Reagents and (iii) Kits (each individually), which report
         shall cite specific goals and objectives in researching, developing and
         commercializing the licensed technology and methodology and progress in
         meeting these goals and objectives. If Genzyme does not receive any
         such report(s) in a timely manner, it shall notify EXACT of such
         delinquency in writing. EXACT shall have thirty (30) days from its
         receipt of such notice to provide Genzyme with any and all overdue
         report(s). Failure by EXACT to provide such overdue report(s) within
         said thirty (30) day period may constitute grounds for termination of
         this Agreement by Genzyme as provided for in Section 7.5 hereof;
         PROVIDED, HOWEVER, that the number of days elapsed since EXACT first
         received notice from Genzyme of the delinquent reports shall be counted
         for purposes of determining the sixty (60) day period described in
         Section 7.5 hereof.

                               ARTICLE 4. PAYMENTS

4.1      In partial consideration for the license granted hereunder, and upon
         execution of this Agreement, EXACT agrees to pay Genzyme [CONFIDENTIAL
         TREATMENT REQUESTED]/*/, which amount shall not be creditable against
         any other amounts payable by EXACT to Genzyme hereunder.

4.2      EXACT shall pay to Genzyme during the term of this Agreement a royalty
         amounting to (a) [CONFIDENTIAL TREATMENT REQUESTED]/*/of Net Service
         Revenues worldwide and (b) [CONFIDENTIAL TREATMENT REQUESTED]/*/of Net
         Sales worldwide.

         /*/ [CONFIDENTIAL TREATMENT REQUESTED] INDICATES MATERIAL THAT HAS BEEN
         OMITTED AND FOR WHICH CONFIDENTIAL TREATMENT HAS BEEN REQUESTED. ALL
         SUCH OMITTED MATERIAL HAS BEEN FILED WITH THE SECURITIES AND EXCHANGE
         COMMISSION PURSUANT TO RULE 406 PROMULGATED UNDER THE SECURITIES ACT OF
         1933, AS AMENDED.

<PAGE>
                                      -7-

4.3      (a) EXACT shall pay Genzyme a minimum royalty of [CONFIDENTIAL
         TREATMENT REQUESTED]/*/ payable within thirty (30) days of the date
         this Agreement is signed on behalf of EXACT for 1999 and on January 1
         of each year thereafter with respect to the licenses granted for
         Diagnostic Services; PROVIDED, HOWEVER, that the minimum royalty for a
         given year shall be creditable against any royalties subsequently due
         during said year under Section 4.2.

         (b) EXACT shall pay Genzyme a minimum royalty of [CONFIDENTIAL
         TREATMENT REQUESTED]/*/ payable on January 1, 2004 and on January 1 of
         each year thereafter with respect to the licenses granted for Licensed
         Reagents and Kits; PROVIDED, HOWEVER, that the minimum royalty for a
         given year shall be creditable against any royalties subsequently due
         during said year under Section 4.2.

         (c) Waiver or deferral of any minimum royalty payment by Genzyme shall
         not be construed as waiver or deferral of any such subsequent payment.

4.4      (a) In the event that the First Commercial Sale of a Diagnostic Service
         by EXACT has not occurred within [CONFIDENTIAL TREATMENT
         REQUESTED]/*/after the Effective Date, EXACT shall pay Genzyme an
         annual maintenance fee of [CONFIDENTIAL TREATMENT REQUESTED]/*/ payable
         on each anniversary of the Effective Date commencing with the
         [CONFIDENTIAL TREATMENT REQUESTED]/*/ anniversary of the Effective
         Date; PROVIDED, HOWEVER, that if EXACT has submitted a BONA FIDE
         application to the U.S. Food and Drug Administration or the equivalent
         authority at that time ("FDA") to obtain final marketing approval for a
         Diagnostic Service within said [CONFIDENTIAL TREATMENT REQUESTED]/*/
         period and EXACT's failure to make such First Commercial Sale is due to
         delays in obtaining such approval that are caused by the FDA and are
         not related to a substantial deficit in said application, then Genzyme
         may elect, in its sole discretion, to extend said [CONFIDENTIAL
         TREATMENT REQUESTED]/*/ period and shall notify EXACT in writing of any
         such determination and election and of the amount of time by which such
         period has been extended; PROVIDED FURTHER that if the parties disagree
         as to whether said application contained a substantial deficit and the
         time for resolution of such deficit, the dispute shall be referred to
         arbitration pursuant to Article 11 hereof and, until final resolution
         of the dispute, EXACT shall deposit any amounts otherwise due and
         payable to Genzyme under this Section 4.4(a) into an escrow account
         established by EXACT exclusively for such purpose in a recognized
         commercial banking institution reasonably selected by EXACT and
         promptly identified by written notice from EXACT to Genzyme. If the
         arbitrator resolves the dispute in favor of Genzyme, then the amounts
         held in escrow plus all interest accrued thereon shall be promptly paid
         to Genzyme in same day funds. Amount payable under this Section 4.4(a)
         shall not be creditable against any royalties or other payments due
         during said year under this Article 4. Waiver or deferral of any
         maintenance fee by Genzyme shall not be construed as waiver or deferral
         of any such subsequent payment.

         (b) In the event that the First Commercial Sale of a Kit by EXACT has
         not occurred within [CONFIDENTIAL TREATMENT REQUESTED]/*/ after the
         Effective Date and the license granted pursuant to Section 2.1 (c)
         hereof has not been terminated by

         /*/ [CONFIDENTIAL TREATMENT REQUESTED] INDICATES MATERIAL THAT HAS BEEN
         OMITTED AND FOR WHICH CONFIDENTIAL TREATMENT HAS BEEN REQUESTED. ALL
         SUCH OMITTED MATERIAL HAS BEEN FILED WITH THE SECURITIES AND EXCHANGE
         COMMISSION PURSUANT TO RULE 406 PROMULGATED UNDER THE SECURITIES ACT OF
         1933, AS AMENDED.
<PAGE>
                                      -8-

         Genzyme pursuant to Section 7.7 hereof, EXACT shall pay Genzyme an
         annual maintenance fee of [CONFIDENTIAL TREATMENT REQUESTED]/*/ payable
         on each anniversary of the Effective Date commencing with the
         [CONFIDENTIAL TREATMENT REQUESTED]/*/ anniversary of the Effective
         Date; PROVIDED, HOWEVER, that if EXACT has submitted a BONA FIDE
         application to the FDA to obtain final marketing approval for a Kit
         within said [CONFIDENTIAL TREATMENT REQUESTED]/*/ period and EXACT's
         failure to make such First Commercial Sale is due to delays in
         obtaining such approval that are caused by the FDA and are not related
         to a substantial deficit in said application, then Genzyme may elect,
         in its sole discretion, to extend said [CONFIDENTIAL TREATMENT
         REQUESTED]/*/ period and shall notify EXACT in writing of any such
         determination and election and of the amount of time by which such
         period has been extended; PROVIDED FURTHER that if the parties disagree
         as to whether said application contained a substantial deficit and the
         time for resolution of such deficit, the dispute shall be referred to
         arbitration pursuant to Article 11 hereof and, until final resolution
         of the dispute, EXACT shall deposit any amounts otherwise due and
         payable to Genzyme under this Section 4.4(b) into an escrow account
         established by EXACT exclusively for such purpose in a recognized
         commercial banking institution reasonably selected by EXACT and
         promptly identified by written notice from EXACT to Genzyme. If the
         arbitrator resolves the dispute in favor of Genzyme, then the amounts
         held in escrow PLUS all interest accrued thereon shall be promptly paid
         to Genzyme in same day funds. Amount payable under this Section 4.4(b)
         shall not be creditable against any royalties or other payments due
         during said year under this Article 4. Waiver or deferral of any
         maintenance fee by Genzyme shall not be construed as waiver or deferral
         of any such subsequent payment.

4.5      EXACT shall pay Genzyme a milestone payment in the amount of
         [CONFIDENTIAL TREATMENT REQUESTED]/*/ within [CONFIDENTIAL TREATMENT
         REQUESTED]/*/ after the first receipt by EXACT of either 510(k)
         clearance or approval of a Pre-Marketing Authorization application
         ("PMA") (or the equivalent of such submissions required at such time)
         for a Kit from the FDA. Such amount shall not be creditable against any
         royalties or other payments due under this Article 4.

4.6      Payment of royalties specified in Section 4.2 shall be made by EXACT to
         Genzyme within forty-five (45) days after March 31, June 30, September
         30 and December 31 each year during the term of this Agreement covering
         Net Sales and Net Service Revenues during the preceding calendar
         quarter. The last such payment shall be made within forty-five (45)
         days after the expiration or earlier termination of this Agreement.

4.7      No multiple royalties shall be payable on any Diagnostic Service,
         Licensed Reagent or Kit because such Diagnostic Service, Licensed
         Reagent or Kit or its practice, manufacture, use, importation or sale
         is or shall be covered by more than one of the Patent Rights.

4.8      All payments to be made under this Article 4 shall be paid in United
         States dollars, in Boston, Massachusetts or at such other place and in
         such other way as Genzyme may reasonably designate in writing, without
         deduction of exchange, collection or other charges. Conversion of
         foreign currency into United States dollars shall be calculated

         /*/ [CONFIDENTIAL TREATMENT REQUESTED] INDICATES MATERIAL THAT HAS BEEN
         OMITTED AND FOR WHICH CONFIDENTIAL TREATMENT HAS BEEN REQUESTED. ALL
         SUCH OMITTED MATERIAL HAS BEEN FILED WITH THE SECURITIES AND EXCHANGE
         COMMISSION PURSUANT TO RULE 406 PROMULGATED UNDER THE SECURITIES ACT OF
         1933, AS AMENDED.
<PAGE>
                                      -9-

         using the applicable exchange rate as published in The Wall Street
         Journal on the date that the payment is first due and payable. If by
         law, regulation or fiscal policy of a particular country, conversion
         into United States dollars or transfers of funds of a convertible
         currency to the Untied States is restricted or forbidden, EXACT shall
         give Genzyme prompt written notice of such restriction or prohibition,
         which notice shall satisfy the forty-five (45) day payment deadline set
         forth in Section 4.6. EXACT shall pay any amounts due to Genzyme
         through whatever lawful methods Genzyme reasonably designates in
         writing; PROVIDED, HOWEVER, that if Genzyme fails to designate such
         payment method within thirty (30) days after Genzyme is notified of the
         restriction, EXACT may deposit such payment in local currency to the
         credit of Genzyme in a recognized commercial banking institution
         reasonably selected by EXACT and promptly identified by written notice
         from EXACT to Genzyme, and such deposit shall fulfill all obligations
         of EXACT to Genzyme with respect to such payment.

4.9      In the event that any payment due hereunder is not made when due, the
         payment shall accrue interest beginning on the first day following the
         due date as herein specified, calculated at the annual rate of the sum
         of (a) two percent (2%) PLUS (b) the prime interest rate quoted by
         BankBoston N.A. on the date said payment is due, the interest being
         compounded on the last day of each calendar quarter; provided, that in
         no event shall said annual rate exceed the maximum legal interest rate
         in Massachusetts. The payment of such interest shall not foreclose
         Genzyme from exercising any other rights it may have as a consequence
         of the lateness of any payment.

4.10     Royalty payments and other payments due to Genzyme under this Agreement
         shall not be reduced by reason of any withholding or similar taxes
         applicable to such payments to Genzyme.

4.11     Genzyme hereby agrees that if, after the Effective Date, (a) Genzyme
         grants a license ("Subsequent Comparable License") to another person
         or entity (other than a wholly-owned subsidiary of Genzyme)
         conveying rights to (i) practice Diagnostic Services in the Field,
         (ii) make, use, offer to sell, sell and import Licensed Reagents for
         use in the Field, or (iii) make, use, offer to sell, sell and import
         Kits for use in the Field, (b) such person or entity intends to sell
         Diagnostic Services, Licensed Reagents or Kits, as applicable, other
         than for research purposes and (c) such Subsequent Comparable
         License has financial terms which, taken as a whole, are more
         favorable to such person or entity than those set forth herein,
         Genzyme shall promptly deliver written notice to EXACT of the grant
         of such Subsequent Comparable License and EXACT shall thereafter have
         sixty (60) days in which to elect to substitute into this Agreement
         all the financial terms and conditions of such Subsequent Comparable
         License by delivering written notice of such election to Genzyme
         within said sixty (60) day period.

                         ARTICLE 5. REPORTS AND RECORDS

5.1      EXACT shall maintain true, accurate and complete books of account,
         records and files containing an accurate record of all data reasonably
         necessary for the full computation and verification of sales and the
         determination of the amounts payable under Article 4 hereof for a
         period of at least four (4) years following the period of each report
         required by Section 5.2 below. Said books and records shall be kept at
         EXACT's principal place of business and shall be in accordance with
         generally accepted accounting principles, consistently applied. Said
         books and records, to the extent not previously audited, shall be
         available for inspection by an independent certified public accountant
         selected by Genzyme (or its licensor of the Patent Rights) and
         reasonably acceptable to EXACT, upon ten (10) business days advance
         written notice and during regular business hours, for three (3) years
         following the end of the calendar year to which they pertain in order
         to enable Genzyme (or its licensor of the Patent Rights) to ascertain
         the correctness of any report and/or payment made under this Agreement.
         Such inspections may be conducted no more than once in any twelve (12)
         month period and, except as provided below, shall be conducted at the
         expense of Genzyme (or its licensor, as the case may be). If such
         examination reveals that royalties have been misstated, any adjustment
         shall be promptly

<PAGE>
                                      -10-

         refunded or paid, as appropriate. Genzyme (or its licensor, as the case
         may be) shall pay the fees and expenses of the accountant engaged to
         perform the audit, unless such audit reveals an underpayment of five
         percent (5%) or more for the period examined, in which case EXACT shall
         pay all reasonable costs and expenses incurred by Genzyme (or its
         licensor, as the case may be) in the course of making such
         determination, including without limitation the fees and expenses of
         the accountant.

5.2      Within forty-five (45) days after March 31, June 30, September 30 and
         December 31, of each year in which this Agreement is in effect, EXACT
         shall deliver to Genzyme full, true and accurate reports of its
         activities relating to this Agreement during the preceding three month
         period. These reports shall include at least the following:

         (a) the total actual billings for Diagnostic Services on a
         country-by-country basis during the applicable period;

         (b) the total gross sales of Licensed Reagents and Kits, each
         individually, on a country-by-country basis during the applicable
         period;

         (c) the calculation of Net Service Revenues and Net Sales on a
         country-by-country basis for the applicable period, including a
         detailed listing of the applicable deductions permitted under Sections
         1.11 and 1.12 hereof on an item-by-item basis and a detailed
         explanation of the calculation of Net Service Revenues and Net Sales of
         any Combination Services or combination products; and

         (d) the calculation of total royalties due in U.S. dollars, together
         with the exchange rates used for conversion, to the extent applicable.

5.3      With each such report, EXACT shall pay to Genzyme the royalties due and
         payable as provided for in Section 4.2. To the extent that royalties
         for the applicable period are creditable against minimum royalties paid
         pursuant to Section 4.3 hereof, EXACT shall so report. If no royalties
         are due, EXACT shall so report.

                   ARTICLE 6. PATENT PROSECUTION; INFRINGEMENT

6.1      The prosecution, filing and maintenance of all patents and the expense
         thereof shall be the responsibility of Genzyme (and/or its licensor of
         the Patent Rights).

6.2      (a) EXACT agrees to provide Genzyme with prompt written notice after
         becoming aware of any infringement of any of the Patent Rights.

         (b) Genzyme (or its licensor, as the case may be) shall have the right,
         under its control and at its expense, to prosecute any third party
         infringement of the Patent Rights or to defend the Patent Rights in any
         declaratory judgment action brought by a third party which alleges the
         invalidity, unenforceability or non-infringement of any Patent Right.
         EXACT agrees to cooperate fully in any action under this Section 6.2,
         provided that Genzyme (or its licensor, as the case may be) reimburses
         EXACT for its reasonable costs and expenses incurred in connection with
         providing such assistance.
<PAGE>
                                      -11-

         (c)      In the event that

                  (i)   EXACT notifies Genzyme that a third party is conducting
                        activities in the Field that infringe the Patent Rights
                        in any country,

                  (ii)  said third party continues to infringe for [CONFIDENTIAL
                        TREATMENT REQUESTED]/*/ after receipt by Genzyme of such
                        notice and does not obtain a license from Genzyme under
                        the applicable Patent Rights within such period, and

                  (iii) EXACT can demonstrate to Genzyme's reasonable
                        satisfaction through written documentation that (A)
                        EXACT has Net Sales or Net Service Revenues in one or
                        more countries in which there is any Valid Claim within
                        the Patent Rights, and (B) the infringing activities of
                        said third party have resulted in annualized income to
                        said third party equal to or greater than (x)
                        [CONFIDENTIAL TREATMENT REQUESTED]/*/ worldwide in
                        countries in which there is any Valid Claim within the
                        Patent Rights (determined based on Net Sales or Net
                        Service Revenues of the [CONFIDENTIAL TREATMENT
                        REQUESTED]/*/ or (y) [CONFIDENTIAL TREATMENT
                        REQUESTED]/*/ of EXACT's annualized Net Sales or Net
                        Service Revenues (as applicable) worldwide in countries
                        in which there is any Valid Claim within the Patent
                        Rights (determined based on Net Sales or Net Service
                        Revenues of the[CONFIDENTIAL TREATMENT REQUESTED]/*/),
                        whichever is greater,

         then, after making such a demonstration, EXACT may withhold up to
         [CONFIDENTIAL TREATMENT REQUESTED]/*/ of the royalty payments that
         would otherwise be payable to Genzyme on Net Services Revenues from
         Diagnostic Services covered in whole or in part by the infringed Patent
         Rights or on Net Sales of Licensed Reagents or Kits covered in whole or
         in part by the infringed Patent Rights, as applicable, in such
         countries until such time as the infringement is abated; PROVIDED,
         HOWEVER, that in the event that Genzyme (or its licensor, as the case
         may be) either (A) fails to use good faith efforts to undertake the
         prosecution of such third party infringement or otherwise Resolve such
         infringement within two hundred and forty (240) days after receipt by
         Genzyme of the notice delivered by EXACT pursuant to clause (c)(i)
         above or (B) delivers written notice to EXACT that Genzyme (or its
         licensor, as the case may be) does not intend to undertake the
         prosecution of such third party infringement, then EXACT may withhold
         one hundred percent (100%) of the aforementioned royalty payments;
         PROVIDED FURTHER that, if EXACT withholds such royalty payments and
         Genzyme (or its licensor, as the case may be) either successfully
         Resolves such infringement or undertakes the prosecution of such third
         party infringement and obtains a favorable judgment, settlement,
         consent judgment or other final disposition of the suit, EXACT shall
         resume full payment of the aforementioned royalties due under this
         Agreement on Net Service Revenues and Net Sales in such countries upon
         receipt of either written notice of the successful abatement of such
         infringement by prosecution or Resolution signed by an officer of
         Genzyme or a copy of an official, written evidence of such favorable
         judgment,

         /*/ [CONFIDENTIAL TREATMENT REQUESTED] INDICATES MATERIAL THAT HAS BEEN
         OMITTED AND FOR WHICH CONFIDENTIAL TREATMENT HAS BEEN REQUESTED. ALL
         SUCH OMITTED MATERIAL HAS BEEN FILED WITH THE SECURITIES AND EXCHANGE
         COMMISSION PURSUANT TO RULE 406 PROMULGATED UNDER THE SECURITIES ACT OF
         1933, AS AMENDED.

<PAGE>
                                      -12-

         settlement, consent judgment or other final disposition; PROVIDED
         FURTHER that in the event that Genzyme (or its licensor, as the case
         may be) undertakes the prosecution of such infringement and obtains a
         favorable settlement, an order to dismiss shall constitute adequate
         official written evidence for purposes of this sentence. For purposes
         of this clause (c), "Resolve(s)" or "Resolution" means the cessation of
         such third party infringement other than as a result of prosecution,
         including without limitation the grant of a nonexclusive license under
         the Patent Rights or the discontinuance by such third party of the
         infringing activities.

         (d) If Genzyme notifies EXACT in writing within ten (10) days of
         receiving written documentation pursuant to Section 6.2(c)(iii) above
         that Genzyme is not reasonably satisfied that EXACT has demonstrated
         conditions sufficient to justify the withholding of royalty payments
         under Section 6.2(c) above, then, until final resolution of the
         dispute, EXACT shall deposit all withheld royalty payments otherwise
         due and payable to Genzyme into an escrow account established by EXACT
         exclusively for such purpose in a recognized commercial banking
         institution reasonably selected by EXACT and promptly identified by
         written notice from EXACT to Genzyme. If the parties are unable to
         resolve the dispute within thirty (30) days after EXACT's receipt of
         Genzyme's notice, then the dispute shall immediately be referred to one
         (1) executive officer of each party, chosen in the sole discretion of
         that party, who shall negotiate with each other in good faith to
         resolve the dispute during the period ending thirty (30) days after the
         date of such referral. If the designated officers of the parties are
         unable to resolve the dispute within such thirty (30) day period, the
         dispute shall be referred to arbitration pursuant to Article 11 hereof.
         If such officers or the arbitrator, as applicable, resolves the dispute
         in favor of Genzyme, then the amounts held in escrow plus all interest
         accrued thereon shall be promptly paid to Genzyme in same day funds and
         EXACT shall resume full payment of royalties under this Agreement.

         (e) In the event that EXACT withholds royalty payments pursuant to
         Section 6.2(c), EXACT shall include the amount of such withheld
         royalties and the basis for the calculation thereof on a
         country-by-country basis in the reports deliverable by EXACT to Genzyme
         pursuant to Section 5.2 hereof as distinct line items.

         (f) EXACT hereby acknowledges and agrees that Roche has rights under
         the Patent Rights under an agreement with JHU and, therefore,
         activities by Roche in accordance with such agreement with JHU will not
         be subject to this Section 6.2.

                         ARTICLE 7. TERM AND TERMINATION

7.1      Unless earlier terminated as hereinafter provided, this Agreement shall
         remain in full force and effect until the expiration of the last to
         expire Patent Rights. Royalties on Net Service Revenues from Diagnostic
         Services and on Net Sales of Licensed Reagents and Kits covered by the
         Gene Patent Rights shall cease upon the expiration of the last to
         expire Gene Patent Right. Royalties on Net Service Revenues of
         Diagnostic Services and on Net Sales of Licensed Reagents and Kits
         covered by the Methodology Patent Rights shall cease upon the
         expiration of the last to expire Methodology Patent Right.
<PAGE>
                                      -13-

7.2      If (a) Genzyme, acting reasonably, determines that EXACT has ceased to
         carry on its business with respect to the performance of Diagnostic
         Services in the Field and/or the provision of Licensed Reagents and/or
         Kits in the Field in any country in North America or Europe for a
         period of more than six (6) months with no plan to resume such business
         within the following three (3) months, then (b) Genzyme shall have the
         right to terminate this Agreement and all rights, privileges and
         license hereunder granted with respect to such Diagnostic Services
         and/or Licensed Reagents and/or Kits, as applicable, upon six (6)
         months prior written notice to EXACT; PROVIDED, HOWEVER, that if EXACT
         is temporarily unable to carry on such business due to a corporate
         reorganization or restructuring of EXACT, then the six (6) month time
         period set forth in clause (a) of this Section 7.2 shall be reasonably
         extended to accommodate such corporate circumstance by a period to be
         mutually agreed upon by the parties, which extension period shall not
         exceed six (6) months. Such termination shall become effective
         immediately upon the conclusion of such notice period unless EXACT
         shall have resumed such business in good faith prior to the expiration
         of such notice period.

7.3      Should EXACT fail to pay Genzyme any amounts as are due and payable
         hereunder, Genzyme shall have the right to terminate this Agreement
         upon forty-five (45) days prior written notice, unless EXACT shall pay
         Genzyme within said forty-five (45) day period such delinquent amounts
         and all interest due and payable thereon. If EXACT shall not have paid
         all such delinquent amounts and interest due and payable thereon within
         said period, Genzyme, at its sole option, may immediately terminate
         this Agreement and all rights, privileges and license hereunder
         granted.

7.4      EXACT shall have the right to terminate this Agreement and all rights,
         privileges and license hereunder granted at any time upon sixty (60)
         days prior written notice to Genzyme.

7.5      Upon any material breach or default of this Agreement by EXACT, other
         than those delineated in Sections 7.2 and 7.3, which shall always take
         precedence in that order over any material breach or default referred
         to in this Section 7.5, Genzyme shall have the right to terminate this
         Agreement and the rights, privileges and license hereunder granted upon
         sixty (60) days prior written notice to EXACT. Such termination shall
         become effective immediately at the conclusion of such notice period
         unless EXACT shall have cured any such breach or default prior to the
         expiration of said sixty (60) day period.

7.6      (a) If no royalties have been paid by EXACT with respect to any
         Diagnostic Service within two (2) years after the First Commercial Sale
         by EXACT of a Diagnostic Service, the rights, privileges and license
         granted under this Agreement to EXACT under Section 2.1 (a) hereof
         shall automatically terminate.

         (b) If no royalties have been paid by EXACT with respect to any
         Licensed Reagent within two (2) years after the First Commercial Sale
         of a Licensed Reagent, the rights, privileges and license granted under
         this Agreement to EXACT under Section 2.1 (b) hereof shall
         automatically terminate.


<PAGE>
                                      -14-

7.7      (a) If EXACT fails to make a 510(k) or PMA submission for a Kit to the
         FDA (or the equivalent of such submissions as may be required by the
         FDA at such time) within five (5) years after the Effective Date,
         Genzyme may, in its sole discretion, elect to terminate the rights,
         privileges and license granted under Section 2.1 (c) hereof in any or
         each country in which Genzyme has Patent Rights unless such license
         grant is sooner terminated according to the terms of this Agreement.

         (b) If EXACT fails to achieve annual Net Sales of Licensed Reagents and
         Kits for use in the Field of ten million dollars ($10,000,000) or more
         within four (4) years after the First Commercial Sale of a Kit, Genzyme
         may, in its sole discretion, elect to terminate the rights, privileges
         and license granted under Section 2.1 (c) hereof in any and each
         country in which Genzyme has Patent Rights unless such license grant is
         sooner terminated according to the terms of this Agreement.

7.8      If EXACT materially fails to perform in accordance with clauses (i),
         (ii) or (iii) of Section 3.1 hereof, Genzyme may elect to terminate the
         rights, privileges and license granted under Section 2.1 with respect
         to the subject matter of the clause or clauses of Section 3.1 under
         which EXACT has materially failed to perform, as set forth in Section
         3.2, hereof upon thirty (30) days prior written notice to EXACT.
         Notwithstanding the foregoing, any termination of the license granted
         under any one clause of Section 2.1 pursuant to this Section 7.8 will
         be effective only with respect to the subject matter of the clause of
         Section 3.1 under which EXACT has materially failed to perform, and the
         remaining clauses of Section 3.1 and the remaining rights granted under
         2.1 shall be unaffected by such termination.

7.9      Upon any termination of this Agreement in its entirety or any of the
         rights, privileges and licenses granted under Section 2.1 hereof, EXACT
         shall be entitled to finish any work-in-progress and to sell any
         completed inventory of Licensed Reagents or Kits, as applicable, which
         remain on hand as of the date of the termination provided that EXACT
         pays Genzyme the royalties applicable to said subsequent sales in
         accordance with the terms and conditions set forth in this Agreement.

7.10     (a) In the event that Genzyme terminates this Agreement and the rights,
         privileges and licenses hereunder granted pursuant to Section 7.2
         above, then Genzyme shall refund to EXACT the PRO RATA share of the
         amount equal to the sum of (i) any payment made by EXACT pursuant to
         Section 4.3 hereof on January 1 of the calendar year in which the
         effective date of such termination falls PLUS (ii) any payment made by
         EXACT pursuant to Section 4.4 hereof on the anniversary of the
         Effective Date immediately preceding the effective date of such
         termination PLUS (iii) one-half of any payment made by EXACT pursuant
         to Section 4.5 hereof if the license granted under Section 2.1 (c) is
         being terminated and if such payment was made by EXACT within the six
         (6) month period immediately preceding the effective date of such
         termination less (iv) the aggregate amount of any payments made by
         Genzyme to JHU in that Year under the JHU License Agreement based on
         the payments described in clauses (i), (ii) and (iii) above.

<PAGE>
                                      -15-

         (b) In the event that Genzyme terminates the license granted under
         Section 2.1 (a) hereof with respect to Diagnostic Services pursuant to
         Section 7.6 or 7.8 hereof, then Genzyme shall refund to EXACT the pro
         rata share of the amount equal to the sum of (i) any payment made by
         EXACT pursuant to Section 4.3(a) hereof on January 1 of the calendar
         year in which the effective date of such termination falls PLUS (ii)
         any payment made by EXACT pursuant to Section 4.4(a) hereof on the
         anniversary of the Effective Date immediately preceding the effective
         date of such termination less (iii) the amount of any payment made by
         Genzyme to JHU in that Year based on the payments described in clauses
         (i) and (ii) above.

         (c) In the event that Genzyme terminates the rights, privileges and
         license granted under Section 2.1 (b) or (c) hereof with respect to
         Licensed Reagents and Kits pursuant to Sections 7.7 or 7.8 hereof, then
         Genzyme shall refund to EXACT the PRO RATA share of the amount equal to
         the sum of (i) any payment by EXACT to Genzyme pursuant to Section
         4.3(b) hereof on January 1 in which the calendar year of the effective
         date of such termination falls PLUS (ii) any payment made by EXACT
         pursuant to Section 4.4(b) hereof on the anniversary of the Effective
         Date immediately preceding the effective date of such termination PLUS
         (iii) one-half of any payment made by EXACT pursuant Section 4.5 hereof
         to if the license granted under Section 2.1 (c) is being terminated and
         if such payment was made to Genzyme within six (6) months immediately
         preceding the effective date of such termination less (iv) the
         aggregate amount of any payments made by Genzyme to JHU in that Year
         based on the payments described in clauses (i), (ii) and (iii) above.

         (d) The PRO RATA share of any amounts to be refunded by Genzyme
         pursuant to this Section 7.10 shall be determined based on either (i)
         the portion of the twelve (12) month period after said anniversary of
         the Effective Date or (ii) the portion of said calendar year, as
         applicable, during which this Agreement shall not be in effect. In no
         event shall any amounts be refundable by Genzyme to the extent they
         have been credited by Genzyme against royalties payable by EXACT in
         accordance with Sections 4.3 and/or 4.4 hereof. Interest paid to
         Genzyme pursuant to Section 4.9 hereof or on any amounts held in escrow
         during the pendency of a dispute shall not be included in the
         calculation of any amounts refundable by Genzyme.

         (e) Any and all amounts refundable by Genzyme to EXACT pursuant to this
         Section 7.10 shall be paid to EXACT within thirty (30) days after the
         applicable effective date of the termination.

7.11     Upon the expiration or the earlier termination of this Agreement for
         any reason, nothing herein shall be construed to release either party
         from any obligation that matured prior to the effective date of such
         expiration or the termination. The provisions of Articles 5, 8, 10, 11,
         13, 18 and 21, Section 4.6, 7.9, 7.10 and this Section 7.11 shall
         survive the expiration or earlier termination of this Agreement.

<PAGE>
                                      -16-

                    ARTICLE 8. INDEMNIFICATION AND INSURANCE

8.1      (a) Subject to the provisions of Section 8.3 hereof, EXACT shall
         indemnify, defend and hold harmless Genzyme, JHU, The John Hopkins
         Health System ("JHHS") and their respective present and former
         officers, directors, trustees, employees, consultants, agents,
         students, faculty, treating and consulting physicians, inventors of the
         Patent Rights, subsidiaries, successors, heirs and assigns
         (collectively, the "Genzyme Indemnitees") against any liability,
         damage, loss or expense (including reasonable attorneys' fees and
         expenses of litigation) incurred by or imposed upon the Genzyme
         Indemnitees, or any one of them, in connection with any claims, suits,
         actions, demands or judgments arising out of (i) the design, sale, use,
         manufacture or promotion by EXACT and its officers, directors,
         employees, representatives and agents, of any process, service or
         product relating to, or developed, manufactured, used or commercialized
         pursuant to, this Agreement and (ii) the practice and use of the Patent
         Rights by EXACT and its officers, directors, employees, representatives
         and agents.

         (b) EXACT's indemnification under this Section 8.1 shall not apply to
         any liability, damage, loss or expense to the extent that it is
         directly attributable to the negligence, reckless misconduct or
         intentional misconduct of the Genzyme Indemnitees.

         (c) EXACT agrees, at its own expense, to provide attorneys to defend
         against any actions brought or filed against any Genzyme Indemnitee
         with respect to the subject of indemnity contained herein, whether or
         not such actions are rightfully brought, such attorneys to be
         reasonably acceptable to Genzyme and not to be subject to any conflict
         of interest in representing any of the Genzyme Indemnitees nor to have
         been deemed within the preceding ten (10) years by any Genzyme
         Indemnitee to have provided unsatisfactory legal representation of such
         Genzyme Indemnitee.

8.2      (a) Subject to the provisions of Section 8.3 hereof Genzyme shall
         indemnify, defend and hold harmless EXACT and its present and former
         officers, directors, employees, agents, consultants, successors, heirs
         and assigns (collectively, the "EXACT Indemnitees") against any
         liability, damage, loss or expense (including reasonable attorney's
         fees and expenses of litigation) incurred by or imposed upon the EXACT
         Indemnitees, or anyone of them, in connection with any claims, suits,
         actions, demands or judgments arising out of (i) the design, sale, use,
         manufacture or promotion by Genzyme and its officers, directors,
         employees, representatives and agents, of any process, service or
         product utilizing the Patent Rights in the Field and (ii) the practice
         and use of the Patent Rights in the Field by Genzyme and its officers,
         directors, employees, representatives and agents.

         (b) Genzyme's indemnification under this Section 8.2 shall not apply to
         any liability, damage, loss or expense to the extent it is directly
         attributable to the negligence, reckless misconduct or intentional
         misconduct of the EXACT Indemnitees.

         (c) Genzyme agrees, at its own expenses to provide attorneys to defend
         against any actions brought or filed against any EXACT Indemnitee with
         respect to the subject of indemnity contained herein, whether or not
         such actions are rightfully brought, such

<PAGE>
                                      -17-

         attorneys to be reasonably acceptable to EXACT and not to be subject to
         any conflict of interest in representing any of the EXACT Indemnitees
         not to have been deemed within the preceding ten (10) years by any
         EXACT Indemnitee to have provided unsatisfactory legal representation
         of such EXACT Indemnitee.

8.3      In the event any such action is commenced or claim made or threatened
         against an indemnified party covered by Section 8.1 or 8.2 hereof, the
         indemnified party shall promptly notify the indemnifying party in
         writing of such event. The failure of indemnified party to deliver
         notice to the indemnifying party within a reasonable time after the
         commencement of any such action, if materially prejudicial to the
         ability of the indemnifying party to defend such action, shall relieve
         the indemnifying party of any liability to the indemnified party under
         this Article 8 solely with respect to such action, but the failure to
         deliver notice to the indemnifying party will not relieve it of any
         liability with respect to such action that it may have to the
         indemnified party otherwise than under this Article 8. The indemnifying
         party shall assume, with the reasonable cooperation of the indemnified
         party, the investigation and defense of, and may settle that part of,
         any such claim or action commenced or made against the indemnified
         party which relates to the indemnifying party's indemnification and the
         indemnifying party may take such other steps as may be necessary to
         protect itself. The indemnifying party shall not be liable to
         indemnified party on account of any settlement of any such claim or
         litigation affected without the indemnifying party's express written
         consent, which consent shall not be unreasonably withheld or delayed.
         The right of the indemnifying party to assume the defense of any action
         shall be limited to that part of the action commenced against an
         indemnified party which relates to the indemnifying party's obligation
         of indemnification and holding harmless.

8.4      (a) Beginning at such time as any Diagnostic Service, Licensed Reagent
         or Kit relating to, or developed pursuant to, this Agreement is being
         made available (other than for the purpose of obtaining regulatory
         approvals) by EXACT, EXACT shall, at its sole cost and expense, procure
         and maintain commercial general liability insurance, applicable
         worldwide, in amounts not less than two million dollars ($2,000,000)
         per incident and two million dollars ($2,000,000) annual aggregate and
         naming Indemnitees as additional insureds. Such commercial general
         liability insurance shall provide (i) product liability coverage and
         (ii) contractual liability coverage for EXACT's indemnification under
         Section 8.1 of this Agreement. If EXACT elects to self-insure all or
         part of the limits described above (including deductibles or retentions
         that are in excess of two hundred and fifty thousand dollars
         ($250,000) annual aggregate) such self-insurance program must be
         acceptable to Genzyme. The minimum amounts of insurance coverage
         required under this Section 8.4(a) shall not be construed to create a
         limit of EXACT's liability with respect to its indemnification
         obligation under Section 8.1 of this Agreement.

         (b) Genzyme shall, at its sole cost and expense, procure and maintain
         commercial general liability insurance, applicable worldwide, in
         amounts not less than two million dollars ($2,000,000) per incident and
         two million dollars ($2,000,000) annual aggregate and naming the EXACT
         Indemnitees as additional insureds. Such commercial general liability
         insurance

<PAGE>
                                      -18-

         shall provide (i) product liability coverage and (ii) contractual
         liability coverage for Genzyme's indemnification under Section 8.2 of
         this Agreement. If Genzyme elects to self-insure all or part of the
         limits described above (including deductibles or retentions that are in
         excess of two hundred and fifty thousand dollars ($250,000) annual
         aggregate) such self-insurance program must be acceptable to EXACT. The
         minimum amounts of insurance coverage required under this Section
         8.4(a) shall not be construed to create a limit of Genzyme's liability
         with respect to its indemnification obligation under Section 8.2 of
         this Agreement.

         (c) Each party shall provide the other with written evidence of such
         insurance upon request of the other party. Each party shall provide the
         other with written notice at least thirty (30) days prior to the
         cancellation, non-renewal or material change in such insurance. If such
         party does not obtain replacement insurance providing comparable
         coverage within such thirty (30) day period, the other party shall have
         the right to terminate this Agreement and the rights, privileges and
         license granted hereunder effective at the end of such thirty (30) day
         period without any notice or additional waiting periods.

         (d) Each party shall maintain such comprehensive general liability
         insurance beyond the expiration or termination of this Agreement during
         (a) the period that any process, service or product relating to, or
         developed pursuant to, this Agreement is being made available (other
         than for the purpose of obtaining regulatory approvals) by EXACT and
         (b) a reasonable period after the period referred to in clause (a)
         above which in no event shall be less than fifteen (15) years.

             ARTICLE 9. REPRESENTATIONS, WARRANTIES AND DISCLAIMERS

9.1      (a) Genzyme hereby represents and warrants to EXACT that it has the
         right and power to enter into this Agreement, to extend the rights and
         licenses granted herein and to perform its obligations hereunder, and
         that this Agreement is a valid and binding agreement, enforceable in
         accordance with its terms.

         (b) Genzyme further represents and warrants to EXACT that Genzyme is
         not in material breach of the JHU License Agreement as of the Effective
         Date, and that Genzyme will use commercially reasonable and diligent
         efforts to comply with all of its material obligations and duties with
         regard to the Patent Rights under the JHU License Agreement, including
         without limitation any provisions of the JHU Agreement as may be
         reasonably necessary to maintain in effect this Agreement or preserve
         EXACT's rights under this Agreement, including without limitation the
         preservation of EXACT's rights hereunder in the event that Genzyme
         shall breach or default on its obligations under the JHU License
         Agreement.

         (b) EXACT hereby represents and warrants to Genzyme that it has the
         right and power to enter into this Agreement and to perform its
         obligations hereunder, and that this Agreement is a valid and binding
         agreement, enforceable in accordance with its terms. EXACT agrees that
         it shall comply with all applicable local, state, Federal and

         /*/ [CONFIDENTIAL TREATMENT REQUESTED] INDICATES MATERIAL THAT HAS BEEN
         OMITTED AND FOR WHICH CONFIDENTIAL TREATMENT HAS BEEN REQUESTED. ALL
         SUCH OMITTED MATERIAL HAS BEEN FILED WITH THE SECURITIES AND EXCHANGE
         COMMISSION PURSUANT TO RULE 406 PROMULGATED UNDER THE SECURITIES ACT OF
         1933, AS AMENDED.

<PAGE>
                                      -19-

         international laws and regulations relating to the development, design,
         manufacture, sale, use in commerce and promotion of Diagnostic
         Services, Licensed Reagents and Kits.

9.2      EXCEPT AS OTHERWISE EXPRESSLY SET FORTH IN SECTION 9.1, GENZYME MAKES
         NO WARRANTY, EXPRESS OR IMPLIED, INCLUDING, WITHOUT LIMITATION, ANY
         IMPLIED WARRANTIES OF MERCHANTABILITY OR OF FITNESS FOR A PARTICULAR
         PURPOSE WITH RESPECT TO ANY PATENT, TRADEMARK, SOFTWARE, NONPUBLIC OR
         OTHER INFORMATION, OR TANGIBLE RESEARCH PROPERTY, LICENSED OR OTHERWISE
         PROVIDED TO EXACT HEREUNDER AND HEREBY DISCLAIMS THE SAME.

9.3      GENZYME DOES NOT WARRANT THE VALIDITY OF THE PATENT RIGHTS LICENSED
         HEREUNDER AND MAKES NO REPRESENTATION WHATSOEVER WITH REGARD TO THE
         SCOPE OF THE LICENSED PATENT RIGHTS OR THAT SUCH PATENT RIGHTS MAY BE
         EXPLOITED BY EXACT WITHOUT INFRINGING OTHER PATENTS.

9.4      NOTWITHSTANDING ANY OTHER PROVISION OF THIS AGREEMENT, EACH OF THE
         PARTIES HERETO DISCLAIMS ALL OBLIGATIONS ON THE PART OF SUCH PARTY FOR
         DAMAGES, INCLUDING BUT NOT LIMITED TO DIRECT, INDIRECT, SPECIAL AND
         CONSEQUENTIAL DAMAGES, ATTORNEYS' AND EXPERTS' FEES AND EXPENSES, AND
         COURT COSTS (EVEN IF SUCH PARTY HAS BEEN ADVISED OF THE PROBABILITY OF
         SUCH DAMAGES, FEES, EXPENSES AND COSTS) ARISING OUT OF OR IN CONNECTION
         WITH THE MANUFACTURE, USE, SALE OR PROVISION OF THE LICENSED REAGENTS,
         DIAGNOSTIC SERVICES UTILIZING THE LICENSED PROCESSES AND KITS BY THE
         OTHER PARTY. EXACT ASSUMES ALL RESPONSIBILITY AND LIABILITY FOR ANY
         LOSS OR DAMAGES CAUSED BY A LICENSED REAGENT, DIAGNOSTIC SERVICE OR KIT
         MANUFACTURED, USED, SOLD OR PROVIDED BY EXACT. GENZYME ASSUMES ALL
         RESPONSIBILITY AND LIABILITY FOR ANY LOSS OR DAMAGES CAUSED BY A
         LICENSED REAGENT, DIAGNOSTIC SERVICE OR KIT MANUFACTURED, USED, SOLD OR
         PROVIDED BY GENZYME.

                               ARTICLE 10. NOTICES

10.1     Any consent, notice or report required or permitted to be given or made
         under this Agreement shall be in writing, delivered (i) by certified or
         registered mail (postage prepaid, return receipt requested), (ii) by
         facsimile (and promptly confirmed by personal delivery, courier or next
         business day service of a nationally recognized courier service of good
         repute), (iii) by a next business day service of a nationally
         recognized courier service of good repute (with evidence of delivery)
         or (iv) by courier (postage prepaid and signature required), and in any
         case addressed to the other party at its address set forth in this
         Article 10, and shall be effective upon receipt by the addressee.

10.2     Reports, notices and other communications from EXACT to Genzyme as
         provided hereunder shall be sent to:

<PAGE>
                                      -20-

                  President, Molecular Oncology Division
                  Genzyme Corporation
                  One Mountain Road
                  P.O.  Box 9322
                  Framingham, MA 01701-9322
                  Facsimile: (508) 271-2604

         with a copy to

                  Chief Legal Officer
                  Genzyme Corporation
                  One Kendall Square
                  Cambridge, MA 02139
                  Facsimile: (617) 252-7553

         or to such other individual or address as shall hereafter be furnished
         by written notice to EXACT in accordance with this Article 10.

10.3     Reports, notices and other communications from Genzyme to EXACT as
         provided hereunder shall be sent to:

                  President
                  EXACT Laboratories, Inc.
                  63 Great Road
                  Maynard, MA 01754
                  Facsimile: (978) 897-3481

or to such other individual or address as shall hereafter be furnished by
written notice to Genzyme in accordance with this Article 10.

                             ARTICLE 11. ARBITRATION

11.1     Any controversy or claim arising out of, or relating to any provisions
         of this Agreement or the breach thereof which cannot otherwise be
         resolved by good faith negotiations between the parties, or by any form
         of Alternate Dispute Resolution other than arbitration which may be
         mutually acceptable to the parties, shall be resolved by final and
         binding arbitration in Boston, Massachusetts under the rules of the
         American Arbitration Association, or the Patent Arbitration Rules if
         applicable, then obtaining.

         The arbitration shall be subject to the following terms:

         (a)      The number of arbitrators shall be one (1).

         (b) The arbitrator shall be an independent, impartial third party
         having no direct or indirect personal or financial relationship to any
         of the parties to the dispute, who has agreed to accept the appointment
         as arbitrator on the terms set out in this Section 11.1.

<PAGE>
                                      -21-

         (c) The arbitrator shall be an active or retired attorney, law
         professor, or judicial officer with at least five (5) years experience
         in the biotechnology or pharmaceuticals industries and a familiarity
         with the laws governing proprietary rights in intellectual property.

         (d) The arbitrator shall be selected as follows:

                  (i)  Each party shall submit a description of the matter to be
                       arbitrated to the American Arbitration Association at its
                       Regional Office in Boston, Massachusetts. Said
                       Association shall submit to the parties a list of the
                       arbitrators available to arbitrate any dispute between
                       them. Thereafter, each party shall select, in numerical
                       order, those persons on said list acceptable as
                       arbitrators and return the same to the Association. The
                       first arbitrator acceptable to both parties shall be
                       deemed the selected arbitrator with respect to the
                       dispute then at issue under this Agreement. In the event
                       of a failure to select a mutually agreeable arbitrator,
                       the Association shall be requested to submit as many
                       subsequent lists of arbitrators as shall be necessary to
                       effect a mutual selection.

                  (ii) If the method of selection set out in paragraph (d)(i)
                       above fails for any reason, then either party may
                       petition any state or federal court in Massachusetts
                       having jurisdiction for appointment of the arbitrator in
                       accordance with applicable law, provided that the
                       arbitrator must satisfy the requirements of paragraphs
                       (b) and (c) above.

         (e) The arbitrator shall announce the decision and/or award in writing
         accompanied by written findings explaining the facts determined in
         support of the decision and/or award, and any relevant conclusions of
         law.

         (f) Unless otherwise provided in this Section 11.1 or extended by
         agreement of the parties, each party shall submit an initial request
         for designation of an arbitrator within thirty (30) days after receipt
         of the first list of available arbitrators pursuant to Section 11.1 (d)
         of this Agreement, the dispute shall be submitted to the arbitrator
         within ninety (90) days after the arbitrator is selected, and a
         decision shall be rendered within thirty (30) days after the dispute is
         submitted.

         (g) The fees of the arbitrator and any other costs and fees associated
         with the arbitration shall be paid in accordance with the decision of
         the arbitrator.

         (h) The arbitrator shall have no power to add to, subtract from, or
         modify any of the terms or conditions of this Agreement. Any award
         rendered in such arbitration may be enforced by either party in either
         the courts of the Commonwealth of Massachusetts, or in the United
         States District Court for the District of Massachusetts, to whose
         jurisdiction for such purposes Genzyme and EXACT each hereby
         irrevocably consents and submits.

11.2     Notwithstanding the foregoing, nothing in this Article shall be
         construed to waive any rights or timely performance of any obligations
         existing under this Agreement.

<PAGE>
                                      -22-

                    ARTICLE 12. RESTRICTIONS ON USE OF NAMES

12.1     EXACT shall not use the name of Genzyme or its divisions, JHU, JHHS or
         their respective directors, officers, trustees, affiliates, employees,
         faculty, students and the inventor(s) of the Patent Rights or any
         adaptations or contractions thereof in any advertising, promotional or
         sales literature without the prior written consent of Genzyme or JHU in
         each case, as applicable; PROVIDED, HOWEVER, that EXACT (a) may refer
         to publications by employees of Genzyme in the scientific literature
         and (b) may state that a license from Genzyme has been granted as
         herein provided. With respect to reports to public agencies that are
         required by law, EXACT shall provide Genzyme with a reasonable
         opportunity to review the use of its name in each such report
         reasonably in advance of its submission.

12.2     EXACT shall not disclose this Agreement or any of the terms or
         conditions of this Agreement to any third party without the prior
         written consent of Genzyme except and to the extent required to comply
         with applicable laws or regulations; provided, that EXACT delivers
         prior written notice to Genzyme of any disclosure required by
         applicable laws or regulations and takes all reasonable and lawful
         actions to obtain confidential treatment for such disclosure and, if
         possible, to minimize the extent of such disclosure.

                               13. CONFIDENTIALITY

13.1     During the term of this Agreement, each party (the "disclosing party")
         may communicate to the other party (the "receiving party") information
         which it considers to be confidential ("Confidential Information"). All
         Confidential Information shall be specifically designated as
         confidential. Such Confidential Information may include, without
         limitation, trade secrets, know-how, inventions, technical data or
         specifications, testing methods, business or financial information,
         research and development activities, product and marketing plans, and
         customer and supplier information. Confidential Information that is
         disclosed in writing shall be marked with a legend indicating its
         confidential status. Confidential Information that is disclosed orally
         or visually shall be documented in a written notice prepared by the
         disclosing party and delivered to the receiving party within thirty
         (30) days of the date of disclosure; such notice shall summarize the
         Confidential Information disclosed to the receiving party and reference
         the time and place of disclosure.

13.2     The receiving party agrees that it shall: (a) maintain all Confidential
         Information in strict confidence, except that the receiving party may
         disclose or permit the disclosure of any Confidential Information to
         its directors, officers, employees, consultants, and advisors who are
         obligated to maintain the confidential nature of such Confidential
         Information and who need to know such Confidential Information for the
         purposes set forth in this Agreement; (b) use all Confidential
         Information solely for the purposes set forth in this Agreement; and
         (c) allow its directors, officers, employees, consultants, and advisors
         to reproduce the Confidential Information only to the extent necessary
         to effect the purposes set forth in this Agreement, with all such
         reproductions being considered Confidential Information.

<PAGE>
                                      -23-

13.3     The obligations of the receiving party under Section 13.2 above shall
         not apply to the extent that the receiving party can demonstrate that
         certain Confidential Information: (a) was in the public domain prior to
         the time of its disclosure under this Agreement; (b) entered the public
         domain after the time of its disclosure under this Agreement through
         means other than an unauthorized disclosure resulting from an act or
         omission by the receiving party; (c) was independently developed or
         discovered by the receiving party without use of the Confidential
         Information; (d) is or was disclosed to the receiving party at any
         time, whether prior to or after the time of its disclosure under this
         Agreement, by a third party having no fiduciary relationship with the
         disclosing party and having no obligation of confidentiality with
         respect to such Confidential Information; or (e) is required to be
         disclosed to comply with applicable laws or regulations, or with a
         court or administrative order, provided, that the disclosing party
         receives prior written notice of such disclosure and that the receiving
         party takes all reasonable and lawful actions to obtain confidential
         treatment for such disclosure and, if possible, to minimize the extent
         of such disclosure.

13.4.    The obligations set forth in this Article 13 shall remain in effect for
         a period of five (5) years after the expiration or the earlier
         termination of this Agreement.

                           ARTICLE 14. PATENT MARKING

14.      EXACT agrees to mark any Kits, Licensed Reagents or promotional
         materials, technical literature and the like that describe Kits,
         Licensed Reagents or Diagnostic Services with all applicable patent
         numbers, and to indicate "Patent Pending" status in accordance with
         each applicable country's patent laws.

                       ARTICLE 15. INDEPENDENT CONTRACTOR

15.      For the purpose of this Agreement and all services to be provided
         hereunder, both parties shall be, and shall be deemed to be,
         independent contractors and not agents or employees of the other.
         Neither party shall have authority to make any statements,
         representations or commitments of any kind, or to take any action, that
         will be binding on the other party.

                            ARTICLE 16. SEVERABILITY

16.      If any one or more of the provisions of this Agreement shall be held to
         be invalid, illegal or unenforceable, the validity, legality or
         enforceability of the remaining provisions of this Agreement shall not
         in any way be affected or impaired thereby unless the invalid
         provisions are of such essential importance to this Agreement that it
         is to be reasonably assumed that the parties would not have entered
         into this Agreement without the invalid provisions.

                          ARTICLE 17. NON-ASSIGNABILITY

17.      Neither this Agreement nor any part hereof shall be assignable by
         either party without the express prior written consent of the other,
         which shall not be unreasonably withheld. Any attempted assignment
         without such consent shall be void. Notwithstanding the foregoing, such
         consent shall not be required for the assignment of this Agreement (i)
         by

<PAGE>
                                      -24-

         EXACT in connection with the sale or transfer of all or substantially
         all of the business or assets of EXACT however structured, or (ii) by
         Genzyme in conjunction with the transfer of all or substantially all of
         the business or assets of Genzyme or all or substantially all of the
         business or assets allocated to its Molecular Oncology Division however
         structured; PROVIDED, in any such case, that the assignor promptly
         notifies the other party hereto of such assignment and the assignee
         assumes all of the assignor's obligations hereunder in writing, with a
         copy of such written assumption (which may be redacted to the extent
         reasonably necessary to protect confidential information) to be
         promptly delivered to the other party hereto.

                          ARTICLE 18. NON-SOLICITATION

18.      During the term of this Agreement and during the period ending two (2)
         years after the expiration or earlier termination of this Agreement,
         neither party shall, without the prior written consent of the other,
         solicit the employment of, or employ, any person in any capacity who,
         at any time during the term of this Agreement, shall have been an
         employee of the other party.

                          ARTICLE 19. ENTIRE AGREEMENT

19.      This Agreement constitutes the entire agreement between the parties
         with respect to the subject matter and supersedes any prior agreements
         and understandings between the parties relating to the subject matter
         hereof. No oral agreement, conversation or representation between any
         officers, agents or employees of the parties hereto either before or
         after the execution of this Agreement shall affect or modify any of the
         terms or obligations herein contained.

                      ARTICLE 20. MODIFICATIONS IN WRITING

20.      No change, modification, extension, termination or waiver of this
         Agreement, or any of the provisions herein contained, shall be valid
         unless made in writing and signed by a duly authorized representative
         of each party.

                            ARTICLE 21. GOVERNING LAW

21.      The validity and interpretation of this Agreement and the legal
         relations of the parties to it shall be governed by the laws of the
         Commonwealth of Massachusetts without regard to the conflict of laws
         provisions thereunder.

                              ARTICLE 22. CAPTIONS

22. The captions are provided for convenience and are not to be used in
construing this Agreement.

                            ARTICLE 23. CONSTRUCTION

23.      Each of the parties agree that this Agreement is the result of mutual
         negotiation and therefore the language herein shall not be
         presumptively construed against either of them.

<PAGE>
                                      -25-

                            ARTICLE 24. COUNTERPARTS

24.      This Agreement may be executed in one or more counterparts, each of
         which shall be deemed to be an original, and all of which together
         shall be deemed to be one and the same instrument.

                           ARTICLE 25. BINDING EFFECT

25.      This Agreement shall be binding upon and inure to the benefit of the
         parties and their respective permitted successors and permitted
         assigns.

                            ARTICLE 26. FORCE MAJEURE

         26. Neither party shall be deemed to be in breach of this Agreement due
         to, or liable to the other party for damages or loss occasioned by
         failure of performance by the defaulting party if the failure is
         occasioned by war, fire, explosion, flood, acts of God, strike or
         lockout, embargo, or any similar cause beyond the control of the
         defaulting party; provided that the party claiming this exception has
         exerted all commercially reasonable and diligent efforts to avoid or
         remedy such event and that such event does not extend for more than
         nine (9) months; provided further that such party provides the other
         party with prompt written notice of any delay or failure to perform
         that occurs by reason of force majeure and continues performance
         hereunder with reasonable dispatch whenever such causes are removed.
         The parties shall mutually seek a resolution of the delay or failure to
         perform in good faith if a force majeure event extends for more than
         nine (9) months, which resolution may be termination of this Agreement.

                        ARTICLE 27. JHU LICENSE AGREEMENT

27.      In the event that Genzyme's license to the Patent Rights under the JHU
         License Agreement is terminated, this Agreement shall remain in effect
         pursuant to the terms of the JHU License Agreement provided that at
         such time EXACT is not in material breach of the provisions of this
         Agreement and agrees to be bound to JHU as a licensor under the terms
         and conditions of this Agreement.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

<PAGE>
                                      -26-

          IN WITNESS WHEREOF, the parties hereto have caused this Agreement to
be executed by their respective duly authorized representatives as of the date
first above written.


GENZYME CORPORATION

By: /s/ Peter Wirth
    -----------------------------------
Name:  Peter Wirth
       --------------------------------
Title: Executive Vice President
       --------------------------------
Date:  March 25, 1999
       --------------------------------

EXACT LABORATORIES, INC.

By: /s/ Donna K. Hazad
    -----------------------------------
Name: Donna K. Hazad
      ---------------------------------
Title: V.P. Business Development
       --------------------------------
Date: March 23, 1999
      ---------------------------------

<PAGE>
                                      -27-

                                   Appendix A

                               Gene Patent Rights

U.S. Patent No. 5,352,775

         AU9213669                  Patent Application No.  W092/13103
         GB 91000962                US Patent No. 5,648,212 (Div. of '775)
         GB 91000963                US Patent No. 5,691,454 (Div. of '775)
         GB 91000974                US Patent No. 5,783,666 (Div. of '775)
         GB 9100975
         EP 569527
         JP 7500241

U.S. Patent No. 5,527,676

         EP 390323
         JP 4004898

<PAGE>
                                      -28-

                                   Appendix B

                            Methodology Patent Rights

Patent Application No. W093/20235 (detecting mammalian nucleic acids from stool)

EP 672181
JP 8504081
U.S.  Patent Application No.  08/861,910