Tosoh Corporation: The Chemistry of Innovation

Tokyo, Japan and San Diego, U.S. - Tosoh Corporation (TSE: 4042) and Gen-Probe (Nasdaq: GPRO) announced today that the companies have cross-licensed intellectual property covering certain nucleic acid testing (NAT) technologies. The licenses, which are effective January 1, 2004, cover products in clinical diagnostics and other related fields.

Tosoh will receive non-exclusive rights to Gen-Probe's proprietary transcription-mediated amplification (TMA) and ribosomal RNA technologies in exchange for two payments in 2004. Additionally, Tosoh will pay Gen-Probe royalties on worldwide sales of products that employ the licensed Gen-Probe technologies.

Gen-Probe will gain access, in exchange for royalties, to Tosoh's patented TRC* amplification and INAF** detection technologies for use with real time TMA.

"The combination of proprietary technologies from Tosoh and Gen-Probe will further support our strategy of positioning Tosoh Bioscience in new emerging growth markets. We look forward to continuing our collaboration with Gen-Probe as Tosoh introduces more products in the future," said Madoka Tashiro, Chairman and CEO of Tosoh Corporation.

"This agreement with Tosoh enables us to realize additional value from our broad patented technologies, gain additional income from new market segments we are not currently targeting, and access additional innovative NAT technologies," said Henry L. Nordhoff, chairman, president and CEO of Gen-Probe.

* Transcription reverse-transcription concerted
** Intercalation activating fluorescence

About Gen-Probe
Gen-Probe Incorporated, founded in 1983, is a global leader in the development, manufacture and marketing of rapid, accurate and cost-effective nucleic acid testing products used for the clinical diagnosis of human diseases and for screening donated human blood. Using its patented NAT technology, Gen-Probe has received FDA approvals or clearances for more than 60 products that detect a wide variety of infectious microorganisms, including those causing sexually transmitted diseases, tuberculosis, strep throat, pneumonia and fungal infections. Additionally, the Company developed and manufactures the only FDA-approved blood screening assay for the simultaneous detection of HIV-1 and HCV, which is marketed by Chiron Corporation. Gen-Probe and Bayer Corporation have formed a collaboration to develop, manufacture and market nucleic acid diagnostic tests for certain viral organisms, and under the agreement Bayer has the right to distribute these tests, including the recently approved VERSANT® HCV Qualitative Assay. Gen-Probe has 20 years of nucleic acid detection research and product development experience, and its products are used daily in clinical laboratories and blood collection centers throughout the world. Gen-Probe is headquartered in San Diego, California and has approximately 700 employees. Additional information about the Company can be found on the Internet at www.gen-probe.com.

Gen-Probe Incorporated
Michael Watts
Senior director, investor relations and corporate communications
+1-858-410-8673
michaelw@gen-probe.com

About Tosoh Corporation
Headquartered in Tokyo, Japan, Tosoh Corporation is a diversified global chemical and specialty materials company. Founded in 1935, the Company has expanded its reach into high value-added businesses such as fine chemicals, scientific instrumentation, thin film materials, and quartzware. Tosoh is a multi-billion dollar corporation that employs more than 9,000 people worldwide and is listed on the Tokyo and Osaka Stock Exchanges.

The Scientific Instruments Division of Tosoh became an internationally recognized pioneer with the introduction of highly sophisticated diagnostic systems such as the AIA Automated Immunoassay Analyzer and Glycohemoglobin HPLC Analyzers. These unique AIA systems have revolutionized immunochemistry and broadened its definition. Tosoh's systems make use of dry stable test packs that utilize magnetic microbeads and monoclonal antibody technology and random access analysis. In addition, Tosoh is a leader in the development and production of high performance liquid chromatography (HPLC) systems and packing materials. In this field, main products include TOYOPEARL®, a chromatographic process media, as well as TSK-GEL®, packed columns for HPLC. More recently, Tosoh has developed a NAT system that can rapidly identify the presence of microorganisms or malignant tumors, while amplifying them in a reduced amount of time. The system is based on a combination of a new amplification reaction and intercalation activating fluorescent probe.

All Tosoh worldwide affiliates under the Scientific Instruments Division provide top-notch products and services under the brand name, Tosoh Bioscience.

For more information and access to all Tosoh Bioscience companies:
www.tosohbioscience.com

International Public Relations
Tosoh Corporation
Michael Hoover
m_hoover@tosoh.co.jp
Tel: +81-3-5427-5118
Fax: +81-3-5427-5198
www.tosoh.com

Disclaimer
This document contains forward-looking statements, including without limitation, statements concerning product development, objectives, goals, and commercial introduction, which involve certain risks and uncertainties. The forward-looking statements are also identified through use of the words "anticipates," "plans," "expects," and other words of similar meaning. Actual results may differ significantly from the expectations contained in the forward-looking statements.