Document:

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                                                                   Exhibit 10.23

                               SEVERANCE AGREEMENT

                                                              January 4, 2001

Mr. Anthony P. Shuber
11 Grant Street
Milford, MA  01757

Dear Tony:

This letter agreement ("Agreement") will confirm the terms of severance payments
due to you by EXACT Sciences Corporation ("EXACT" or the "Company") in the event
your employment is terminated pursuant to Section 1 herein.

1.   Subject to the conditions set forth below, you will be entitled to receive
     "Severance Payments" (as set forth below in Section 2) for a period of
     twelve (12) months following the occurrence of any one of the events set
     forth in (i), (ii) or (iii) below within one year following the closing of
     (A) the sale by the Company of all or substantially all of its assets, or
     (B) the merger or consolidation of the Company with or into another entity
     in a transaction where the shares of the Company's capital stock
     outstanding immediately prior to the closing of such merger or
     consolidation represent or are converted into or exchanged for shares that
     represent less than a majority of the shares of capital stock of the
     resulting or surviving entity outstanding immediately after the closing of
     such merger or consolidation (each of the foregoing being referred to as
     "Business Event"):

                    (i)  the termination of your employment for any reason other
                         than Cause, for purposes of this Agreement, "Cause"
                         shall mean termination for any one of the following
                         reasons: (i) your gross negligence in the performance
                         of your duties as an employee and officer of the
                         Company (as determined by a majority of the directors
                         of the Company other than, if applicable, you) or
                         (ii) criminal misconduct by you in connection with
                         the performance of your duties as an employee and
                         officer of the Company; or

                    (ii) you suffer a diminution in job responsibility or a
                         reduction in compensation; or

                   (iii) the Company moves your place of employment more than
                         35 miles from Company's current office location in
                         Maynard, Massachusetts.

Notwithstanding, this Paragraph 1, the issuance by the Company of its capital
stock in an equity financing, either in a private or public transaction, shall
not constitute a Business Event.

         2. The Severance Payments will equal salary continuation at a rate
equal to your base salary at the time of your termination of employment from
EXACT. The Severance Payments will be paid in accordance with EXACT's then
existing payroll practices as such practices may be established or modified from
time to time. The Severance Payments shall be subject to applicable federal,
state and local withholding and payroll taxes. You will only be

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Mr. Anthony P. Shuber
January 4, 2001
Page 2

entitled to Severance Payments upon the occurrence of the events specified in
Section 1 of this Agreement. You will not be entitled to any Severance Payments
or other benefits if you voluntarily resign from EXACT or if your employment is
terminated by EXACT for Cause.

         3. Prior to, and as a condition of, receiving the Severance Payments
set forth in this Agreement, you agree to sign a full and comprehensive release
in a form and of a scope acceptable to the Company and you at the time of your
termination of employment. EXACT shall have no obligation to pay you any
Severance Payments unless and until it receives this release executed by you.

         4. If you breach your obligations under the Employee Non-Disclosure and
Developments Agreement and Non Competition Agreement executed between you and
EXACT, the Company may immediately cease payment of all Severance Payments set
forth in this Agreement. The cessation of any Severance Payments shall be in
addition to, and not as an alternative to, any other remedies at law or in
equity available to EXACT, including the right to seek specific performance or
an injunction.

         5. Nothing in this Agreement is intended, or shall be construed, to
restrict or otherwise limit EXACT's right to terminate your employment with or
without Cause and with or without notice. This letter is not a guarantee of
continued employment, it being understood you are and continue to be employed
at-will.

         6. Breach of any of the terms of this Agreement by you shall be
considered a material breach of this Agreement. In the event of such a breach,
EXACT shall be released from any obligations to make any Severance Payments
under this Agreement or, if any such payments have been made, EXACT shall be
entitled to recover from you any amounts already paid under this Agreement in
addition to any and all of its remedies under law arising of such breach.

         7. This Agreement sets forth the entire Agreement of the parties with
respect to the subject matter hereof and may not be changed orally.

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Mr. Anthony P. Shuber
January 4, 2001
Page 3

         Please indicate your acceptance of this Agreement by signing the
enclosed copy of this letter and returning it to me.

                                    Very truly yours,

                                    /s/ Anthony P. Shuber
                                    ---------------------------
                                    Name: Anthony P. Shuber
                                    Title: Vice President of Molecular Biology

                                    /s/ Don M. Hardison
                                    ---------------------------
                                    Name: Don M. Hardison
                                    Title: President<PAGE>

                                                                 Exhibit 10.26

                                WARRANT AGREEMENT

                                December 28, 2000

EXACT Sciences Corporation
(the "Corporation")
63 Great Road
Maynard, MA  01754

         Re:      Issuance of Warrant to Purchase Shares of Common Stock of the
                  Corporation
                  -------------------------------------------------------------

Dear Sirs:

         The undersigned subscribing investor (the "Investor") hereby agrees as
follows:

         1. ISSUANCE OF WARRANT TO PURCHASE SHARES OF COMMON STOCK OF THE
CORPORATION (THE "WARRANT SHARES"). For good and valuable consideration, the
sufficiency and receipt of which is hereby acknowledged, and subject to the
terms and conditions set forth in this Warrant Agreement, the Corporation agrees
to issue to the Investor a warrant in the form attached hereto as EXHIBIT A (the
"Warrant" and together with the Warrant Shares, the "Shares") to purchase 48,125
shares of common stock, $.01 par value per share (the "Common Stock") at a price
of $10.9091 per Share.

         2. CERTAIN REPRESENTATIONS OF THE INVESTOR. The Investor hereby
represents and warrants to the Corporation as follows, and the Investor
acknowledges that the Investor has full knowledge that the Corporation intends
to rely on such representations and warranties:

            (a) THE INVESTOR HAS READ CAREFULLY AND UNDERSTANDS THIS WARRANT
AGREEMENT AND HAS CONSULTED HIS, HER OR ITS OWN ATTORNEY, ACCOUNTANT OR
INVESTMENT ADVISER WITH RESPECT TO THE INVESTMENT CONTEMPLATED HEREBY AND ITS
SUITABILITY FOR THE INVESTOR. THE INVESTOR UNDERSTANDS THAT THE SHARES
CONSTITUTE A SPECULATIVE INVESTMENT AND ENTAIL A HIGH DEGREE OF RISK.

            (b) The Corporation has made available to the Investor, during the
course of this transaction and prior to the issuance of the Warrants, the
opportunity to ask questions of and receive answers from representatives of the
Corporation concerning the terms and conditions of the issuance of the Warrant
and the sale of Shares upon exercise of the Warrant, and to obtain any
additional information relative to the financial data and business of the
Corporation, to the extent that the Corporation possesses such information or
can acquire it without unreasonable effort or expense.
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         (c) The Investor understands that the Investor may have to bear the
economic risk of his, her or its investment for an indefinite period; that
neither the Warrant nor the Warrant Shares have been registered under the
Securities Act of 1933 (the "Act") or under any state securities law and,
therefore, cannot be resold unless it is subsequently registered under the Act
or unless an exemption from such registration is available; that the Investor is
purchasing the Shares for investment for the account of the Investor and not
with any view toward resale or other distribution thereof; that the Investor
agrees not to resell or otherwise dispose of all or any part of the Shares,
except as permitted by law; that the Corporation does not have any intention of
registering the Shares under the Act or of supplying the information which may
be necessary to enable the Investor to sell the Shares; and that Rule 144 under
the Act may not be available as a basis for exemption from registration of any
Shares thereunder. The Investor further understands that the Corporation does
not now and will not, for the foreseeable future, be able to pay any dividends
on the Shares; that the policy of the Corporation will be to retain earnings, if
any, for investment in the Corporation; and that the Corporation may in the
future issue additional securities that will have the effect of diluting the
Investor's percentage ownership of the Corporation.

         (d) One or more of the categories set forth below correctly and in all
respects describes the Investor, and the Investor has so indicated by signing
his, her or its name, or by directing its duly authorized representative to sign
in its name and on its behalf, on the blank line or lines following the category
or categories which so describe him or it.

             (i) The Investor is a natural person whose net worth, either
individually or jointly with such person's spouse, at the time of his, her or
its purchase, exceeds $1,000,000.

________________________________________________________________________________

             (ii) The Investor is a natural person who had individual income in
excess of $200,000, or joint income with that person's spouse in excess of
$300,000, in 1998 and 1999 and reasonably expects to reach the same income level
in 2000.

________________________________________________________________________________

             (iii) The Investor is an organization described in Section
501(c)(3) of the Internal Revenue Code, corporation, Massachusetts or similar
business trust, or partnership, not formed for the specific purpose of acquiring
the Shares, with total assets in excess of $5,000,000.

________________________________________________________________________________

             (iv) The Investor is a trust, with total assets in excess of
$5,000,000, not formed for the specific purpose of acquiring the Shares, whose
purchase is directed by a sophisticated person as described in Rule
506(b)(2)(ii) of Regulation D.

________________________________________________________________________________

             (v) The Investor is an executive officer of the Corporation.

________________________________________________________________________________
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             (vi) The Investor is a "qualified institutional buyer" within the
meaning of SEC rule 144A, as presently in effect.

________________________________________________________________________________

                  (e) The Investor has no need for liquidity in connection with
his, her or its purchase of the Shares.

                  (f) The acquisition of the Warrant and the purchase of the
Warrant Shares upon exercise of the Warrant by the Investor is consistent with
the general investment objectives of the Investor.

                  (g) The Investor first learned of the offer of Shares by the
Corporation in the State or other local jurisdiction listed in the residence
address of the Investor set forth in EXHIBIT B, and intends that the state
securities laws of that State or other local jurisdiction alone govern this
transaction.

                  (h) The Investor was not solicited by the Corporation's
registration statement on Form S-1 filed with the SEC on October 27, 2000, or
any amendments thereto, in connection with its acquisition of the Shares.

                  (i) The Investor is a large institutional "accredited
investor" as defined under Rule 501(a)(1), (a)(2), (a)(3) or (a)(7) promulgated
under the Securities Act and it was not organized for the specific purpose of
acquiring the Shares.

                  (j) The Investor currently owns Common Stock, Series C
Convertible Preferred Stock and Series D Convertible Preferred Stock of the
Corporation and has a preexisting relationship with the Corporation.

         3. CLOSING. The closing of the issuance of the Warrant shall take place
at the offices of Testa, Hurwitz & Thibeault, LLP, High Street Tower, 125 High
Street, Boston, Massachusetts 02110, on December 28, 2000 or on such later date
as shall be selected by the Corporation, (the "Closing").

         4. CONDITIONS TO CLOSING. The Investor's obligation to complete the
acquisition of the Warrant is subject to the fulfillment, prior to or at the
closing, of each of the following conditions:

            4.1 REPRESENTATION AND WARRANTIES. The Corporation shall represent
and warrant to the Investor that at the time of the closing:

            (a) ORGANIZATION AND STANDING OF THE CORPORATION, ETC. The
     Corporation is duly and validly organized and validly existing as a
     corporation under the laws of the State of Delaware, and has all requisite
     power and authority under its Certificate of Incorporation and By-Laws to
     enter into and carry out the terms of this Warrant Agreement, to conduct
     its business and to issue the Warrant and to sell the Warrant Shares upon
     exercise of the Warrant.

            (b) ISSUANCE OF THE WARRANT AND THE WARRANT SHARES. All action
     required to be taken by the Corporation as a condition to the issuance of
     the Warrant and sale of the Warrant Shares upon exercise of the Warrant has
     been taken and the Warrant Shares upon issuance to the Investor will be
     duly and validly issued, fully-paid and non-assessable shares of Common
     Stock of the Corporation.

         5. SURVIVAL OF AGREEMENTS, REPRESENTATIONS AND WARRANTIES ETC. All
agreements, representations and warranties made by or on behalf of the
Corporation or the Investor in this Warrant Agreement shall survive the
execution and delivery of this Warrant Agreement, any investigation at any time
made by the Investor or on its behalf, and the sale and purchase of the Warrant
Shares and payment therefor.
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         6. LOCK-UP AGREEMENT. The Investor agrees that in connection with an
underwritten public offering of Common Stock, upon the request of the Company or
the principal underwriter managing such public offering, neither the Warrant nor
the Warrant Shares may be sold, offered for sale or otherwise disposed of
without the prior written consent of the Corporation or such underwriter, as the
case may be, for a period of not more than 180 days following the effective date
of the registration statement of such public offering. Notwithstanding the
foregoing, the Investor is only obligated under this Section 8 for a period no
greater than the period that all of the members of the Board of Directors of the
Corporation have agreed to be similarly bound.

            6.1 RESTRICTIVE LEGEND. All certificates representing the Warrant
and any of the Warrant Shares, shall have affixed thereto a legend in
substantially the following form, in addition to any other legends that may be
required under federal or state securities laws, and may be removed after the
180 day period following the effective date of the registration statement of
such public offering:

                    "The Warrant and the Warrant Shares issuanble upon exercise
                    of the Warrant are subject to restrictions set forth in a
                    certain Warrant Agreement and its attached exhibits (the
                    "Agreement") between the Company and the registered owner of
                    these shares, and such Agreement is available for inspection
                    without charge at the office of the Secretary of the
                    Company."

         7. EXPENSES. Each party hereto will pay its own expenses relating to
this Warrant Agreement and the issuance of the Warrant and the purchase of the
Warrant Shares upon exercise of the Warrant. Without limiting the foregoing,
each of the Investor and the Corporation (i) represents that it has not retained
any broker or agent in connection with the sale of Shares and (ii) will
indemnify and hold harmless the other against any fee, commission, or the like
payable by it in connection with the offer and sale of the Shares.

         8. NOTICES. Notices given hereunder shall be deemed to have been duly
given on the date of personal delivery or on the date of postmark, if mailed by
registered or certified mail, to the party being notified at his address
specified EXHIBIT B attached hereto or such other address as he may subsequently
notify the other party in writing.

         9. AMENDMENTS. This Warrant Agreement or any term hereof may not be
changed, waived, discharged or terminated except with the written consent of the
Investor and the Corporation.

         10. GENERAL. This Warrant Agreement (i) shall be binding upon the
Investor and the legal representatives, successors and assigns of the Investor,
(ii) shall be governed, construed and enforced in accordance with the internal
laws of the Commonwealth of Massachusetts (except insofar as affected by the
State securities, "Blue Sky" laws or other securities laws of the jurisdiction
in which the offerings described herein have been made to the Investor as
aforesaid), and (iii) constitutes the entire agreement of the Corporation and
the Investor with respect to the sale and purchase of the Shares.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]
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         IN WITNESS WHEREOF, the undersigned has executed this Warrant Agreement
as of the day and year first written above.

                                     Mayo Foundation for Medical
                                       Education and Research

                                     /s/ Harry N. Hoffman
                                     ------------------------------------
                                     By: Assistant Treasurer
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The foregoing Warrant
Agreement is hereby accepted
by the Corporation.

EXACT SCIENCES CORPORATION

By: /s/ Don M. Hardison
    ------------------------------------
       Don M. Hardison
       President
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                                                                       EXHIBIT A

                                 FORM OF WARRANT
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                                                                       EXHIBIT B

1.    Typed or printed name and residence address of Investor:

                  Mayo Foundation for Medical Education and Research
                  c/o Harry Hoffman, Treasury Services
                  200 First Street, SW
                  Rochester, MN  55902

2.    Preferred address for receiving communications: (Do not complete if same
      as above.)

3.    Number of Shares issuable upon exercise of the Warrant:

                  48,125

4.    Aggregate exercise price for Warrant Shares (@ $10.9091 per Share):

                  $190,909.25

5.    Social Security or Federal Tax identification Number of the Investor:

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