American Journal of Preventive Medicine Reports Stool-Based DNA Testing Patient-Preferred over FOBT and Colonoscopy for Colorectal Cancer Screening.

MARLBOROUGH, Mass. -- EXACT Sciences Corporation (NASDAQ: EXAS) announced today that the American Journal of Preventive Medicine has published the results of a patient preference study, which found that patients perceived stool-based DNA testing to have many advantages over both fecal occult blood testing (FOBT) and colonoscopy, and preferred stool-based DNA testing for their routine colorectal cancer screening.

"It is important that people have options for colorectal cancer screening," said Dr. Paul C. Schroy III, MD, MPH, Boston University School of Medicine, lead investigator of the study. "While there are several screening tests available, far too many people are not getting screened for what could be a curable disease. Stool-based DNA testing is a novel screening option that offers a convenient, non-invasive and potentially more acceptable alternative to existing screening tests for an average-risk patient population. Any test that increases the number of people who get screened effectively for colorectal cancer is a test that should be made available to patients as a standard of care."

Schroy's study was designed to compare patient perceptions of stool-based DNA testing, FOBT and colonoscopy and elicit screening preferences, following a patient's completion of all three tests. The study included more than 4,000 patients, making it one of the largest studies ever done comparing patient attitudes about colorectal cancer screening tests. Overall, the study showed, with a high degree of statistical significance, that a higher percentage of patients preferred stool-based DNA testing (45%) to both FOBT (32%) and to colonoscopy (15%) for routine screening. This study was conducted in conjunction with EXACT Sciences' multi-center study of its stool-based DNA test, PreGen-Plus(TM), which showed a four-fold sensitivity advantage versus Hemoccult II, the most widely prescribed FOBT on the market today, as published in the December 23, 2004 issue of the New England Journal of Medicine.

Colorectal cancer is the second leading cause of cancer-related death among men and women in the United States. Despite widespread support for regular screening, however, the majority of Americans over the age of 50 have never been screened by any method, allowing the high mortality associated with this disease to persist. Previous studies have identified a number of practical reasons for this low adherence rate, including negative attitudes towards FOBT and invasive tests such as colonoscopy.

Patient preference for stool-based DNA testing is also evident in post-market data for PreGen-Plus, the commercially available version of the stool-based DNA test, which indicates that more than half of the people surveyed who have used PreGen-Plus had never been screened before. In addition, more than ninety percent of these people found PreGen-Plus easy/very easy to use, and the same percentage would be likely/highly likely to use it again. These data were presented in abstract form at the most recent annual meeting of the North American Menopause Society.

"The patient preference data compiled by Dr. Schroy provide more evidence for the important role that stool-based DNA testing can have in the armamentarium of tools available to detect, and fight, colorectal cancer," stated Don Hardison, EXACT Sciences' President and CEO. "Too many people are dying needlessly from this disease. The prospective study data have been confirmed by our commercial experience with PreGen-Plus, which suggests that, when provided with an option that they prefer, people will in fact get screened for colorectal cancer - and getting screened saves lives."

About EXACT Sciences Corporation

EXACT Sciences Corporation is a leader in rapidly applying genomics knowledge to develop effective, 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, the Company's research and development strategies and programs and their likely future success, the development of new technologies to enhance the sensitivity of its products in the detection of cancer, 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 ability to convince medical practitioners to order tests using EXACT Sciences' technologies; the ability to increase the performance of the PreGen-Plus test; 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; 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; and the possibility that other companies will develop and market novel or improved methods for detecting colorectal cancer. 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 SEC filings.