For Immediate Release

MARLBOROUGH, Mass., (Sep 29, 2005) - Cytyc Corporation today announced 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 testing of ThinPrep Pap Test samples by molecular diagnostic methods. The approval allows the removal of up to 4 ml from the PreservCyt(R) sample vial before preparing the ThinPrep Pap Test slide to better facilitate ancillary testing.

"The testing of the residual specimen in the PreservCyt sample vial for Chlamydia trachomatis, Neisseria gonorrheae and HPV is currently conducted in many laboratories based on FDA approvals previously granted to Cytyc. The ability to remove an aliquot before preparing the ThinPrep Pap Test slide greatly improves the implementation of amplified molecular testing, particularly in high-volume laboratories," said James Linder, M.D., Cytyc's chief medical officer.

"We are extremely pleased to provide this capability to our customers. The ThinPrep Pap Test is the only liquid-based cytology method to have FDA approval for specific molecular diagnostic tests. Our ThinPrep Pap Test collection vial serves as a platform, enabling ThinPrep plus Imaging and testing for important sexually transmitted infections from a single patient specimen. This newly approved capability to remove a sample for molecular testing from the patient specimen vial before processing on the ThinPrep System should facilitate broader application of these molecular tests," said Patrick J. Sullivan, Cytyc's chairman, president, and chief executive officer.