EXHIBIT 10.28 AMENDMENT NO. 1 TO FULL RECOURSE PROMISSORY NOTE This Amendment No. 1, dated as of November 30, 2001, is entered into by and among Exact Sciences Corporation, a Delaware corporation (the "Company") and John A. McCarthy Jr. (the "Maker")....

                                                                   EXHIBIT 10.28

                AMENDMENT NO. 1 TO FULL RECOURSE PROMISSORY NOTE

This Amendment No. 1, dated as of November 30, 2001, is entered into by and
among Exact Sciences Corporation, a Delaware corporation (the "Company") and
Xxxx X. XxXxxxxx Xx. (the "Maker").

WHEREAS, the Maker entered into a Full Recourse Promissory Note with the Company
dated as of November 30, 2000 (the "Note"), the provisions of which grant the
Company and the Maker the right to amend the terms of the Note; and

         WHEREAS, in light of the decrease in market interest rates and to
encourage the Company's employees including the Maker to remain in the employ of
the Company, the Company desires to amend the interest rate on the Note and all
other promissory notes issued by the Company's employees to the Company to more
closely reflect current market interest rates.

         NOW, THEREFORE, in consideration of the promises and the agreements
         herein contained, and intending to be bound hereby, the parties hereby
         agree as follows: The first sentence of the first paragraph of the Note
         shall be amended and restated in its entirety to read as follows:

         "FOR VALUE RECEIVED, Xxxx X. XxXxxxxx Xx. (the "Maker") promises to pay
         to the order of EXACT Sciences Corporation, a Delaware corporation (the
         "Holder"), at its principal office at 00 Xxxxx Xxxx, Xxxxxxx,
         Xxxxxxxxxxxxx 00000, or such other place as may be designated from time
         to time in writing by the Holder, or its assigns, the principal sum of
         $300,000, together with accrued interest on the principal of this Note
         outstanding at the rate of 5% per year."

         In all other respects, the Note shall remain in full force and effect.

This Amendment No. 1 may be executed in any number of counterparts and by
different parties hereto in separate counterparts, with the same effect as if
all parties had signed the same document. All such counterparts shall be deemed
an original, shall be construed together and shall constitute one and the same
instrument.

                                 EXACT SCIENCES CORPORATION


                                 By:   /s/ Xxx X. Xxxxxxxx
                                       -----------------------------------------
                                 Name:     Xxx X. Xxxxxxxx
                                 Title:    Chief Executive Officer and President
ACKNOWLEDGED AND AGREED



/s/ Xxxx X. XxXxxxxx Xx.
-----------------------
    Xxxx X. XxXxxxxx Xx.