Geron Corporation Announces Publication of Genetic Data Describing Genes Linked to the Growth and Differentiation of Human Embryonic Stem Cells.

Business Editors/Health/Medical Writers

MENLO PARK, Calif.--(BUSINESS WIRE)--May 17, 2004

Geron Corporation (Nasdaq:GERN) today announced the publication of research results that identify genes active in human embryonic stem cells (hESCs) and in hESCs undergoing differentiation. The work was performed under Geron's prior collaboration with Celera Genomics Group (NYSE:CRA), an Applera Corporation business, and was published online today in the journal Nature Biotechnology (www.nature.com/nbt). This work has elucidated signaling pathways operative in hESCs that likely play key roles in their growth and differentiation. This information will facilitate derivation of useful differentiated cell types for therapy, and may also lead to the development of novel tools for drug discovery.

As part of their collaboration, Geron and Celera produced cDNA libraries from undifferentiated hESCs and three partially differentiated progeny cell populations. Over 148,000 physical clones were sequenced representing more than 32,000 transcripts, expressed genes in the human genome. These data were analyzed to identify over 600 genes preferentially upregulated or downregulated in undifferentiated hESCs and to assemble a blueprint of molecular pathways functional in hESC differentiation. All 148,000 sequences are available from the National Center for Biotechnology Information (www.ncbi.nlm.nih.gov).

"This work represents a unique large scale comparison of genes expressed in undifferentiated hESCs and their differentiated progeny," said Ralph Brandenberger, Ph.D., Geron's group leader of bioinformatics and lead author on the paper. "This approach allows fine discrimination of gene expression patterns between directly related cell types permitting identification of genes likely to be important in the maintenance of undifferentiated hESCs and in the transition to the early differentiated state. The data also show differences between mouse and human embryonic stem cells and the different mechanisms each uses to maintain the undifferentiated 'pluripotent' state."

"Controlling the growth and differentiation of hESCs is key to developing well characterized cell populations for therapeutic use," stated Thomas B. Okarma, Ph.D., M.D., Geron's president and chief executive officer. "The information provided by this study has resulted in new inventions which may help us achieve this. Under the Geron-Celera agreement, these inventions are owned by Geron."

Geron is a biopharmaceutical company focused on developing and commercializing therapeutic and diagnostic products for cancer based on its telomerase technology, and cell-based therapeutics using its human embryonic stem cell technology.

This news release may contain forward-looking statements made pursuant to the "safe harbor" provisions of the Private Securities Litigation Reform Act of 1995. Investors are cautioned that such forward-looking statements in this press release regarding potential applications of Geron's technologies constitute forward-looking statements that involve risks and uncertainties, including, without limitation, risks inherent in the development and commercialization of potential products and need for future capital. Actual results may differ materially from the results anticipated in these forward-looking statements. Additional information on potential factors that could affect our results and other risks and uncertainties are detailed from time to time in Geron's periodic reports, including the quarterly report on Form 10-Q for the quarter ended March 31, 2004.