Contacts:

Sharon Tetlow Vice President, Chief Financial Officer 343 Oyster Point Blvd. South San Francisco, CA 94080 650-246-6403 stetlow@diadexus.com

Emory University Dr. Mary Severson Assistant Vice President and Director Office of Technology Transfer 2009 Ridgewood Drive Atlanta, GA 30322 404-727-2211 msevers@emory.edu

DIADEXUS AND EMORY UNIVERSITY ENTER CANCER RESEARCH COLLABORATION TARGETING NOX-1 ENZYME

South San Francisco, CA and Atlanta, GA - (BW HealthWire) - September 9, 2002 - diaDexus, Inc. and Emory University today announced that they have entered into a collaboration to further evaluate the biological role of Nox-1, a novel cancer target and enzyme known to convert oxygen into "reactive oxygen." As part of the collaboration, diaDexus will have the exclusive right to develop and commercialize therapeutic and diagnostic products targeting or otherwise based on Nox-1. Financial terms were not disclosed.

Reactive oxygen species are created during cellular metabolism and include molecules such as hydrogen peroxide, nitric oxide and superoxide. They have been implicated in both cellular damage and cell to cell communication. In addition to its enzymatic function as an oxidase, Nox-1 is also a transmembrane protein that appears to be significantly more abundant on the surface of certain solid tumors compared to normal tissue. Therefore, the collaboration will also focus on the role of Nox-1 in colorectal cancer and other solid tumors.

Scientists at Emory University School of Medicine, led by J. David Lambeth, M.D., Ph.D., Professor of Pathology and Laboratory Medicine, have reported that the additional production of the Nox-1 protein in mouse cells resulted in the important observation that the cells became cancer-like and proliferated more rapidly than normal cells. When injected into mice, these transformed cells were extremely tumorogenic.

In addition, research recently published in the January 22, 2002 issue of the Proceedings of the National Academy of Sciences (PNAS) by scientists at Emory and Harvard Medical School establishes that Nox-1 is a potent trigger of angiogenesis, which is the growth of microscopic blood vessels. Angiogenesis serves many physiological and pathological roles, including nourishing cancerous cells that leads to unregulated cell growth and tumor formation.

"We are delighted to collaborate with Dr. Lambeth, a renowned expert in the biology of reactive oxygen and its effects on cellular processes, and his distinguished team at Emory," said Ron Lindsay, Ph.D., Chief Scientific Officer of diaDexus. "They have generated compelling data linking Nox-1 overexpression and generation of reactive oxygen to tumor growth. This program builds on our own internal studies linking Nox-1 overexpression with colon cancer."

Said Dr. Lambeth, "We are excited and optimistic about the prospects of using Nox-1 as both a diagnostic marker and as a therapeutic target for treatment of colon cancer. We feel fortunate to have found in diaDexus such an enthusiastic, insightful and energetic collaborator, and look forward to working with them to move this technology forward."

diaDexus, based in South San Francisco, California is focused on the discovery, development, and commercialization of novel, patent protected diagnostic and therapeutic products with high clinical value. diaDexus has utilized genomics and bioinformatics to identify thousands of disease-associated molecular targets. For more information, please visit http://www.diaDexus.com.

Emory University is a leading research university with one of the fastest-growing research enterprises in the nation. In addition to its undergraduate and graduate schools in the arts and sciences, Emory is known for its highly ranked professional schools of medicine, public health, nursing, business, law, and theology, as well as for its state-of-the-art research facilities and demanding academics. Overall, Emory is ranked as the 18th-best university in the country by U.S. News & World Report. Emory's School of Medicine is ranked 20th among research-oriented medical schools, the Goizueta Business School's MBA program is ranked 22nd and the School of Law is ranked 22nd. Located 15 minutes from downtown Atlanta, Emory's 631-acre campus is positioned along the Clifton Corridor, which also includes the U.S. Centers for Disease Control and Prevention and the American Cancer Society. Emory's Robert W. Woodruff Health Sciences Center includes Emory Healthcare, the most comprehensive health care delivery system in Atlanta. For more information, please visit http://www.emory.edu.