Cytyc Corporation Forms Alliance With Y-ME National Breast Cancer Organization.

MARLBOROUGH, Mass. -- Partnership Aimed at Raising Awareness of Partial Breast Irradiation and Less Invasive Treatment Options for Breast Cancer Patients

Cytyc Corporation (NASDAQ: CYTC) today announced a partnership in support of its MammoSite(R) Radiation Therapy System with Y-ME National Breast Cancer Organization. Y-ME is a leading patient advocacy group whose mission is to ensure that no one faces breast cancer alone. The purpose of the alliance is to broaden public understanding of less invasive treatment options for early-stage breast cancer. The program will include education on the benefits of partial breast irradiation (PBI) and breast-conserving therapy. MammoSite Radiation Therapy, the most widely-practiced form of partial breast irradiation, has been used to treat thousands of women at hundreds of U.S. centers.

The efficacy of this therapy is supported by a study published in the Journal of the National Cancer Institute (2003). The study found that, over the course of five years, partial breast irradiation produces comparable results to whole-breast radiation therapy in preventing breast cancer recurrence in women with early-stage breast cancer who are treated with breast-conserving therapy. To develop additional clinical data, the National Surgical Adjuvant Breast and Bowel Project (NSABP) and the Radiation Therapy Oncology Group (RTOG), supported by the National Cancer Institute (NCI), recently initiated a multi-center study comparing whole breast irradiation with PBI over the long term. The study will follow 3,000 women for 10 years in order to further define the role of partial breast irradiation for the local management of early stage breast cancer.

"We are pleased to be working with Y-ME to help educate women about their options for the treatment of early stage breast cancer," said Patrick J. Sullivan, Cytyc's chairman, president, and chief executive officer. "With the initiation of the NCI's important study, more women will be seeking information about PBI. Through its extremely valuable resources, including its web site, literature, newsletter, and 24-hour Hotline, Y-ME is in touch with many people who are interested in learning about treatment options such as partial breast irradiation. We look forward to being aligned with this well-respected group."

"We don't give medical advice--we're not physicians--but we can help people make educated decisions by giving them information about procedures and treatment options," said Margaret C. Kirk, chief executive officer for Y-ME. "We are encouraged when there are developments that can help treat this devastating disease and potentially improve the quality of life for breast cancer patients."

The mission of Y-ME National Breast Cancer Organization is to ensure, through information, empowerment, and peer support, that no one faces breast cancer alone. To fulfill this mission, Y-ME provides information and support to those touched by breast cancer at www.y-me.org and through the 24-hour Y-ME National Breast Cancer Organization Hotline, which is staffed entirely by trained peer counselors who are breast cancer survivors. Additionally, affiliates throughout the nation provide services such as support groups, early detection workshops, wigs and prostheses for women with limited resources, and advocacy on breast cancer related policies in their respective communities. Many programs and services are available in Spanish. Peer support is provided in nearly 150 languages on the Hotline.

Cytyc Corporation is a leading women's health company that designs, develops, manufactures, and markets innovative and clinically effective products. Cytyc products cover a range of women's health applications, including cervical cancer screening, breast cancer risk assessment, treatment of excessive menstrual bleeding, and treatment of breast cancer.

Cytyc is traded on The Nasdaq Stock Market under the symbol CYTC. Cytyc and MammoSite are registered trademarks of Cytyc Corporation.

Forward-looking statements in this press release are made pursuant to the provisions of Section 21E of the Securities Exchange Act of 1934. Investors are cautioned that statements in this press release which are not strictly historical statements, including, without limitation, statements relating to Cytyc's future financial condition, operating results and economic performance, and management's expectations regarding future growth opportunities, product acceptance and business strategy, constitute forward-looking statements. These statements are based on current expectations, forecasts and assumptions that are subject to risks and uncertainties, which could cause actual outcomes and results to differ materially from those statements. Risks and uncertainties include, among others, dependence on key personnel, customers and proprietary technology, uncertainty of product development efforts and product acceptance, management of growth and product diversification, entry into new market segments, risks associated with litigation, the effective integration of acquired businesses and technologies, competition and competitive pricing pressures, risks associated with the FDA regulatory approval processes and healthcare reimbursement policies, introduction of technologies that are disruptive to Cytyc's business and operations, the impact of new accounting requirements and governmental rules and regulations, as well as other risks detailed in Cytyc's filings with the Securities and Exchange Commission, including under the heading "Certain Factors Which May Affect Future Results" in its 2004 Annual Report on Form 10-K and its most recent Quarterly Report on Form 10-Q filed with the Commission. Cytyc cautions readers not to place undue reliance on any such forward-looking statements, which speak only as of the date they were made. Cytyc disclaims any obligation to publicly update or revise any such statements to reflect any change in its expectations or events, conditions, or circumstances on which any such statements may be based, or that may affect the likelihood that actual results will differ from those set forth in the forward-looking statements.