<PAGE>

                                                                   Exhibit 10.17


                       RESTRICTED STOCK PURCHASE AGREEMENT


         AGREEMENT, effective as of November 30, 2000, by and between John A.
McCarthy, Jr. (the "Purchaser") and EXACT Sciences Corporation (the "Company"),
a Delaware corporation.

         1. SALE. Pursuant to the exercise of the Option as set forth in the
Non-Qualified Stock Option Agreement dated October 2, 2000, the Company hereby
issues to the Purchaser 15,000 shares (the "Shares") of Common Stock, par value
$.01 per share (the "Common Stock"), of the Company, for an exercise price of
$20.00 per share (the "Exercise Price"), to be paid by a promissory note dated
as of the date hereof by and between the Company and the Purchaser (the
"Promissory Note"). Simultaneously with the execution of the Promissory Note and
the purchase of the Shares, Purchaser shall execute a pledge agreement dated as
of the date hereof between the Purchaser and the Company. This sale is made
pursuant and subject to the following terms and conditions.

         2. RECEIPT OF EXERCISE PRICE AND SHARES. The Company hereby
acknowledges receipt of the consideration set forth in Paragraph 1 hereof the
Promissory Note, as payment in full of the Exercise Price of the Shares, in
accordance with Section 1. The Purchaser hereby acknowledges receipt of stock
certificates representing the Shares.

         3. COMPANY PURCHASE OPTION.

                  3.1 OPTION TO THE COMPANY TO PURCHASE THE SHARES. The
Purchaser hereby grants to the Company an irrevocable right and option (the
"Purchase Option") to purchase all or any portion of the Shares on the terms and
conditions set forth in this Agreement.

         At any time within (90) ninety days after the Purchaser ceases to be an
employee of the Company or a subsidiary of the Company, subject to the
provisions of Section 3.2 in the event of a termination for any reason other
than Cause (as defined in Section 3.2), the Company shall have the right to
exercise the Purchase Option and to purchase from the Purchaser (or his estate,
it being understood that Shares released from the Purchase Option under this
Agreement shall pass upon the Purchaser's death to the Purchaser's estate), for
an amount per Share equal to the Exercise Price (the "Option Price"), up to that
fraction of the Shares specified in the following table:

<TABLE>
<CAPTION>

       IF CESSATION OF EMPLOYMENT OCCURS                    % OF SHARES SUBJECT TO PURCHASE OPTION
<S>                                                        <C>

       Before October 2, 2001                                              100%

       On or after October 2, 2001                                          75%

       On the 1st day of each calendar month                Percentage of shares subject to Purchase
       thereafter                                           Option on the 1st day of the prior calendar
                                                                        month less 2.083%

       On or after October 2, 2004                                         None
</TABLE>

<PAGE>

                                      -2-


                  3.2 EARLY TERMINATION OF PURCHASE OPTION. Notwithstanding the
foregoing, in the event the Purchaser continues to be employed by the Company on
the earlier to occur of the following events prior to four years from the date
of this Agreement:

                  (a) In the case of a Business Event as defined in subsection
(B), to the extent there are Shares subject to the Company's Purchase Option,
all Shares shall vest as if the vesting date was one year prior to the date set
forth in Section 3.1 hereof and the Purchase Option shall expire with respect to
such Shares which become vested pursuant hereto. It is the intention of the
parties that the acceleration of vesting provided by this paragraph shall not in
any way suspend the operation of the vesting schedule set forth in Section 3.1,
but rather the effect of such acceleration shall be to compensate the Purchaser
by deeming him to have (for purposes of determining the number of Shares subject
to the Company's Purchase Option only) an additional year of service with the
Company from and after the Business Event and the Company shall have no further
right and option to repurchase all or any portion of those Shares which become
vested pursuant hereto.

                  (b) If in conjunction with 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") and any of the following events, the Company's
Purchase Option shall immediately expire as to all remaining Shares:

                  (i)      the termination by the Company of the Purchaser's
                           employment with the Company for any reason other than
                           Cause. For purposes of this agreement "Cause" shall
                           mean (A) the Purchaser's gross negligence in the
                           performance of his duties as an employee and officer
                           of the Company (as determined by a majority of the
                           directors of the Company other than, if applicable,
                           the Purchaser) or (B) criminal misconduct by the
                           Purchaser in connection with the performance of his
                           duties as an employee and officer of the Company; or

                  (ii)     the Purchaser suffers a diminution in job
                           responsibility or a reduction in compensation; or

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

         Notwithstanding the foregoing, 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.

                  3.3 EXERCISE OF OPTION. The Purchase Option shall be exercised
by written notice delivered or mailed by the Company to the Purchaser (or his
estate), accompanied by payment by check for the Option Price for the Shares
being repurchased.

                  3.4 DELIVERY OF REPURCHASED SHARES. The Purchaser agrees that
he (or his executors or administrators or other legal representative, as the
case may be) shall promptly deliver to the Company, at the Company's principal
office, certificates for any Shares which are repurchased by the



<PAGE>

                                      -3-

Company pursuant to this Section 3, and that such certificates shall be duly
endorsed in blank for transfer to the Company; provided, however, that if the
Purchaser fails to deliver such certificates to the Company on or before the
fifth day following delivery to the Purchaser by the Company of the notice and
payment required by subsection 3.3, the Shares repurchased shall be deemed to be
transferred to the Company on such date, and all rights of the Purchaser with
respect to such Shares shall thereupon cease.

                  3.5 SHARES NOT REPURCHASED. In the event the Company declines
in writing to repurchase any or all of the Shares or does not exercise its
option for repurchase as provided herein, the Shares shall remain the property
of the Purchaser.

         4. ADDITIONAL SHARES. If, from time to time during the term of the
Purchase Option, there is any stock dividend or liquidating dividend of cash
and/or property, stock split, subdivision, or other change in the character or
amount of any of the outstanding Common Stock of the Company, then in such event
any and all new, substituted or additional securities or other property to which
the Purchaser is entitled by reason of his ownership of the Shares shall be
immediately subject to the Purchase Option and be included in the term "Shares"
for all purposes of the Purchase Option with the same force and effect as the
Shares presently subject thereto. After each such event, the Option Price per
share upon exercise of the Purchase Option shall be appropriately adjusted.

         5. INVESTMENT REPRESENTATIONS. The Purchaser represents, warrants and
covenants that:

         (i)      The Purchaser is purchasing the Shares for his own account for
                  investment only, and not with a view to, or for sale in
                  connection with, any distribution of the Shares in violation
                  of the Securities Act of 1933 (the "Securities Act"), or any
                  rule or regulation under the Securities Act.

         (ii)     The Purchaser is aware of the Company's business affairs and
                  financial condition, and has had such opportunity as he has
                  deemed adequate to obtain from representatives of the Company
                  such information as is necessary to permit the Purchaser to
                  evaluate the merits and risks of his investment in the
                  Company.

         (iii)    The Purchaser can afford a complete loss of the value of the
                  Shares and is able to bear the economic risk of holding the
                  Shares for an indefinite period.

         (iv)     The Purchaser has sufficient experience in business, financial
                  and investment matters to be able to evaluate the risks
                  involved in the purchase of the Shares and to make an informed
                  investment decision with respect to such purchase.

         (v)      The Purchaser understands that: (A) the Shares will not be
                  registered under the Securities Act and are "restricted
                  securities" within the meaning of Rule 144 and/or Rule 701
                  under the Securities Act; (B) the Shares cannot be sold,
                  transferred or otherwise disposed of unless they are
                  subsequently registered under the Securities Act or an
                  exemption from registration is then available; (C) in any
                  event, the exemption from registration under Rule 144 or
                  otherwise will not be available for at least one year and even
                  then may not be available unless a public market then exists
                  for the Common Stock, adequate information concerning the
                  Company is available to the public, and other terms and
                  conditions of Rule 144 are complied with, and (D) there is
                  currently no effective registration statement on file with the
                  Securities and Exchange Commission with

<PAGE>

                                      -4-

                  respect to any stock of the Company and the Company has no
                  obligation to register the Shares under the Securities Act.

         6. LEGENDS.

                  6.1 RESTRICTED STOCK AGREEMENT LEGEND. All certificates
representing the Shares which are subject to the Purchase Option shall have
affixed thereto a legend substantially in the following form:

                  "The securities represented by this certificate are subject to
                  certain restrictions on transfer and to certain rights of the
                  Company to purchase such securities as set forth in a
                  Restricted Stock Purchase Agreement between the corporation
                  and the registered holder (or his predecessor in interest), a
                  copy of which is available for inspection without charge at
                  the principal office of the corporation."

         7. RESTRICTIONS ON TRANSFER. Except as otherwise provided in this
Section 7, the Purchaser shall not sell, assign, transfer, pledge, hypothecate
or otherwise dispose of, by operation of law or otherwise (collectively
"transfer") any of the Shares, or any interest therein, unless and until such
Shares are no longer subject to the Company's Purchase Option. Notwithstanding
the foregoing the Purchaser may transfer Shares by gift, provided that such
Shares shall remain subject to this Agreement (including without limitation the
Purchase Option and the restrictions on transfer set forth herein), and such
permitted transferee shall, as a condition to such transfer, deliver to the
Company a written instrument confirming that such transferee shall be bounded by
all of the terms and conditions of this Agreement.

         8. EFFECT OF PROHIBITED TRANSFER. The Company shall not be required (a)
to transfer on its books any of the Shares which shall have been sold or
transferred in violation of any of the provisions set forth in this Agreement,
or (b) to treat as owner of such Shares or to pay dividends to any transferee to
whom any such Shares shall have been so transferred.

         9. RIGHT OF STOCKHOLDER. Subject to the provision of Sections 7 and 8
above, the Purchaser shall, during the term of this Agreement, exercise all
rights and privileges of a stockholder of the Company with respect to the
Shares.

         10. FURTHER INSTRUMENTS AND ACTIONS. The parties agree to execute such
further instruments and to take such further action as may reasonably be
necessary to carry out the intent of this Agreement.

         11. NOTICES. Any notice required or permitted hereunder shall be given
in writing and shall be deemed effectively given upon personal delivery or upon
deposit with the United States Post Office, by registered or certified mail,
addressed to each other party hereto at his address hereinafter shown below his
signature or at such other address as such party may designate by ten (10) days
advance written notice to all other parties hereto.

         12. EMPLOYMENT STATUS. Nothing contained in this Agreement shall be
construed as giving the Purchaser any right to continue employment with the
Company.

         13. WITHHOLDING TAXES. The Purchaser acknowledges and agrees that any
tax consequences of the purchase, exercise and sale of Shares will be borne by
Purchaser and not by the Company and that the Company has the right to deduct
from payments of any kind otherwise due to the Purchaser any federal, state or
local taxes of any kind required by law to be withheld with respect to the
Shares.

<PAGE>

                                      -5-

         14. MISCELLANEOUS

                  14.1. ENTIRE AGREEMENT. This Agreement constitutes the entire
contract between the parties hereto with regard to the subject matter hereof.

                  14.2. GOVERNING LAW. This Agreement shall be governed by and
construed under the laws of the State of Delaware as such laws are applied to
contracts entered into and performed in such state.

                  14.3. SUCCESSOR AND ASSIGNS. Except as otherwise expressly
provided in this Agreement, the provisions hereto shall inure to the benefit of,
and be binding upon, the successors and assigns of the parties hereto.

                  14.4. AMENDMENTS. The terms and provisions of this Agreement
may not be modified or amended except in a writing executed by the parties
hereto.


<PAGE>

                                      -6-

         IN WITNESS WHEREOF, this Agreement shall be effective as of the date
first above written.


EXACT SCIENCES CORPORATION                      PURCHASER



By: /s/ Don M. Hardison                         By: /s/ John A. McCarthy, Jr.
    -----------------------------                   ---------------------------
    Don M. Hardison                                 John A. McCarthy, Jr.
    President