Exhibit 99.1

PreGen-Plus Meets All Criteria of Blue Shield's California Technology
                           Assessment Forum

    MARLBOROUGH, Mass.--(BUSINESS WIRE)--March 1, 2005--EXACT Sciences
Corporation (NASDAQ:EXAS) today announced that the California
Technology Assessment Forum (CTAF), a program of the Blue Shield of
California Foundation, unanimously agreed at its recent meeting that
colorectal cancer screening with PreGen-Plus meets all five of CTAF's
assessment criteria for new medical technologies. PreGen-Plus is EXACT
Sciences' non-invasive stool-based DNA screening technology for the
early detection of colorectal cancer. CTAF has confirmed that it will
recommend approval of PreGen-Plus to the Blue Shield of California
Foundation Board of Trustees at its meeting in May. Although approval
by CTAF does not guarantee coverage of PreGen-Plus by Blue Shield of
California, it is a critical first step.
    CTAF's assessment criteria are substantially similar to the
assessment criteria used by other Blue Cross Blue Shield technology
assessment groups across the country in evaluating new medical
technologies for approval. In order to meet CTAF's assessment
criteria, new technologies must, among other things, be supported by
convincing medical evidence that their use leads to improved health
outcomes.
    "CTAF's positive review of PreGen-Plus is gratifying on many
levels" said Don Hardison, EXACT's President and Chief Executive
Officer. "While we have always believed that our technology addressed
a critical healthcare need, we now have CTAF's important independent
evaluation, in addition to our compelling clinical evidence to date,
that our technology improves health outcomes for the general
population. With new and costly colorectal cancer treatment drugs
coming to market, we believe that our test is a critical prevention
tool for those payors looking to reduce costs associated with late
stage colorectal cancer. We intend to encourage other large payor
organizations across the country to follow CTAF's lead in approving
PreGen-Plus to focus on colorectal cancer prevention in the general
population."

    About the California Technology Assessment Forum

    The California Technology Assessment Forum (CTAF) is a program of
the Blue Shield of California Foundation. The California Technology
Assessment Forum is a community forum dedicated to objectivity and
transparency regarding medical technologies; a community forum for
dialog and decisions regarding the safety and effectiveness of new and
emerging technologies; and a public benefit for California. The
California Technology Assessment Forum reviews approximately 15 to 20
new and emerging medical technologies each year. www.ctaf.org.

    About Blue Shield of California Foundation

    Blue Shield of California Foundation was formed by Blue Shield of
California, a not-for-profit corporation with more than 3.2 million
members, 4,300 employees and 20 offices throughout California. The
Blue Shield of California Foundation provides charitable contributions
and conducts research and supports programs with an emphasis on
domestic violence prevention, medical technology assessment and
reducing the number of uninsured. For more information, visit the Blue
Shield of California website at www.mylifepath.com or the Foundation
at www.blueshieldcafoundation.org.

    About EXACT Sciences Corporation

    EXACT Sciences Corporation is a leader in applying genomics
knowledge to develop patient-friendly screening methods to detect
cancer early, to assist physicians in saving patients' lives. Its
first commercial test, PreGen-Plus(TM), is used for screening
colorectal cancer in the average-risk population. Colorectal cancer,
which is the most deadly cancer among non-smokers, is curable if
detected early. Despite the availability of colorectal cancer
screening and diagnostic tests for more than 20 years, the rate of
early detection of colorectal cancer remains low, and deaths from
colorectal cancer remain high. EXACT Sciences believes its
genomics-based technologies will enable early detection of colorectal
cancer so that more people can be effectively treated. Founded in
1995, EXACT Sciences is based in Marlborough, Mass. Detailed
information on EXACT Sciences and PreGen-Plus can be found on the
World Wide Web at www.exactsciences.com and www.pregenplus.com.

    Certain statements made in this press release that are not based
on historical information are express or implied forward-looking
statements relating to, among other things, EXACT Sciences'
expectations concerning, among other things, its business outlook and
business momentum (including the size of the potential market for its
technologies), the likelihood of third-party reimbursement of its
technologies, and the effectiveness and market acceptance of its
technologies. These statements are neither promises nor guarantees,
but are subject to a variety of risks and uncertainties, many of which
are beyond EXACT Sciences' control, and which could cause actual
results to differ materially from those contemplated in these
forward-looking statements. In particular, the risks and uncertainties
include, among other things, the ability of EXACT Sciences to become
profitable; the success of its strategic relationship with LabCorp;
its ability to license certain technologies or obtain raw materials
for its technologies; the ability to convince Medicare and other
third-party payors to provide adequate reimbursement for EXACT
Sciences' products and services; the ability to convince medical
practitioners to order tests using EXACT Sciences' technologies; the
ability to increase the performance of the PreGen-Plus test; the
ability of EXACT Sciences or LabCorp to lower costs through automating
and simplifying key operational processes; the inclusion of
PreGen-Plus in cancer screening guidelines; the number of people who
decide to be screened for colorectal cancer using EXACT Sciences'
technologies; competition; the ability to comply with federal and
state statutes and regulations relating to EXACT Sciences' products
and services, including FDA requirements, the U.S. Department of
Transportation and the Clinical Laboratory Improvement Amendments; the
ability to protect EXACT Sciences' intellectual property and the cost
of enforcing or defending EXACT Sciences in litigation relating to
intellectual property rights; the possibility that other companies
will develop and market novel or improved methods for detecting
colorectal cancer; and the ability to raise additional capital on
acceptable terms. Existing and prospective investors are cautioned not
to place undue reliance on these forward-looking statements, which
speak only as of the date hereof. EXACT Sciences undertakes no
obligation to update or revise the information contained in this press
release, whether as a result of new information, future events or
circumstances or otherwise. For additional disclosure regarding these
and other risks faced by EXACT Sciences, see the disclosure contained
in EXACT Sciences' public filings with the Securities and Exchange
Commission including, without limitation, its most recent Annual
Report on Form 10-K and subsequent quarterly reports on Form 10-Q
filed with the SEC.

    CONTACT: Media:
             Fleishman-Hillard
             Christine Regan, 617-267-8223
             reganc@fleishman.com
             or
             Investor Relations & Corporate Communications:
             EXACT Sciences
             Amy Hedison, 508-683-1252
             ahedison@exactsciences.com