For Immediate Release

MARLBOROUGH, Mass., (Sep 08, 2005) - Cytyc Corporation announced today that the U.S. Food and Drug Administration (FDA) has approved a Pre-Market Approval Supplement for the ThinPrep(R) Pap Test related to the detection of endocervical and endometrial glandular lesions. The enhanced labeling cites multiple peer-reviewed publications that report on the improved ability of the ThinPrep(R) System to detect glandular disease versus the conventional Pap smear. The labeling further states that the results of these studies are consistent in showing more frequent biopsy confirmation of abnormal glandular findings by ThinPrep technology compared to conventional cytology. Thus, the finding of a glandular abnormality on a ThinPrep Pap Test slide merits increased attention for definitive evaluation of potential endocervical or endometrial pathology. The ThinPrep Pap Test is the only cervical cancer screening technology to gain expanded labeling claims related to the detection of glandular abnormalities.

"This is another significant milestone for the ThinPrep Pap Test," said Patrick J. Sullivan, Cytyc's chairman, president, and chief executive officer. "An enhanced label for the detection of glandular lesions is an important clinical advance for patients and their physician and provides yet another unique differentiator for our cervical screening technology."

The frequency of cervical adenocarcinoma has increased during the past two decades, so that this cell type is now responsible for the majority of increased cases of cervical cancer reported in women under 35. In the United States, while the age-adjusted rate of the more common squamous cell carcinoma declined by 42 percent from the mid-1970's to the late 1990's, the age-adjusted incidence rates for adenocarcinoma increased by 29 percent. The proportion of adenocarcinoma increased 107 percent relative to all cervical cancers and 95 percent relative to squamous cell carcinoma(1). There are similar trends worldwide and most are attributable to increases in the younger age groups (25-49 years).

"The publications supporting this FDA approval indicate both improved detection of endocervical adenocarcinoma and more accurate classification of glandular disease with the ThinPrep Pap Test. This is critical for the gynecologist to optimally manage the patient," said James Linder, M.D., Cytyc's senior vice president and chief medical officer.

The ThinPrep Pap Test is currently the most widely used method for cervical cancer screening in the United States and the only method approved by the U.S. FDA as "significantly more effective than the conventional Pap smear for the detection of Low-grade Squamous Intraepithelial (LSIL) and more severe lesions in a variety of patient populations." The ThinPrep Pap Test is also the only liquid-based cytology approved by the FDA for HPV testing and the only cytology system approved by the FDA for chlamydia and gonorrhea testing directly from the ThinPrep collection vial.