Affymetrix is acquiring eBioscience for $330 million in cash to strengthen its offerings in the oncology and immunology research markets. The privately-held San Diego biotech is a leading supplier of flow cytometry and immunoassay reagents for immunology and oncology research and diagnostics.

Affymetrix, an early leader in gene chip technology, has experienced declining revenues from its gene expression microarrays with increased competition in the space. The Santa Clara, California-based genomics firm sees the acquisition of eBioscience as transformational in expanding its product offerings to growing markets in translational medicine, oncology, and immunology. Affymetrix estimates the market opportunity to be nearly $3 billion annually.

“This transaction places Affymetrix at the forefront of immunology and oncology, two of the fastest growing segments of molecular and translational medicine,” says Stephen Fodor, founder and chairman of Affymetrix. “eBioscience complements our traditional businesses of genomics and cytogenetics, and dramatically strengthens our foundation in molecular diagnostics.”

eBioscience is a profitable company with 2011 sales expected to exceed $70 million, and a profit margin before taxes of approximately 30 percent. The purchase price represents approximately 4.5 times 2011 revenue. Affymetrix expects to fund the deal half with cash on hand, and half with committed debt. The deal is expected to close by the end of the year. The Santa Clara firm expects to maintain eBioscience’s management team and operations in San Diego.