Response Genetics Expands Sales Force to Cover Major National Oncology Markets and Meet Higher Demand for its ResponseDX Tests

Response Genetics, Inc. (Nasdaq: RGDX), a company focused on the development and sale of molecular diagnostic tests for cancer, announced today it will triple the size of its sales force to meet higher demand for its ResponseDX™ genetic testing services.

Since their launch in September 2008, more than 500 ResponseDX: Lung™ and ResponseDX: Colon™ tests have been sold, exceeding the company’s initial sales goal. The company has also experienced a reorder rate of more than 90 percent. As a result of this initial rapid adoption, Response Genetics has decided to increase its sales force, which initially focused on the California market, to begin serving most major national markets.

“The promise of personalized medicine is quickly becoming a reality for patients with lung and colon cancer through diagnostic tests such as those developed by Response Genetics,” said Heinz-Josef Lenz, M.D., a professor of medicine at USC’s Keck School of Medicine, as well as the scientific director of the Cancer Genetics Unit and associate director of the Gastrointestinal Oncology Program at the USC Norris Comprehensive Cancer Center. “ResponseDX™ tests are quickly becoming part of routine testing to increase efficacy for our patients.”

“We are encouraged by the early sales and rapid initial adoption of our first commercially available genetic tests — ResponseDX: Lung™ and ResponseDX: Colon™ — and are adjusting our sales strategy accordingly to meet this higher demand,” said Kathleen Danenberg, Response Genetics’ president and CEO. “We attribute this in part to a greater market understanding and acceptance of genetic testing for cancer patients as well as our successful reimbursement strategy.”

ResponseDX™ genetic tests are also available through NeoGenomics Laboratories, the exclusive national clinical reference laboratory authorized to offer Response Genetics’ proprietary tests. All tests are performed through Response Genetics’ CLIA-certified laboratory.

About ResponseDX™ Tests

Response Genetics has developed PCR-based genetic tests — ResponseDX: Lung™ and ResponseDX: Colon™ — to help physicians with therapeutic treatment decisions in patients with non-small cell lung cancer (NSCLC) and colorectal cancer (CRC). The proprietary ResponseDX™ panels include three key genes: excision repair cross-complementing factor 1 (ERCC1), thymidylate synthase (TS) and epidermal growth factor receptor (EGFR). These tests also include the analysis of K-ras gene (KRAS) mutations, which are a strong predictor of non-response to and no benefit from EGFR inhibitors. Response Genetics’ KRAS mutation analysis provides one of the fastest turnaround times in the industry and accurate results on the smallest biopsies. The benefit for patients is that in many cases, no tissue samples other than the pre-treatment diagnostic biopsy will be required for the biomarker analysis. Using ResponseDX™ testing, clinicians may make better treatment decisions via a cost-effective panel approach.

About Response Genetics, Inc.

Response Genetics, Inc. (“RGI”) (the “Company”) (Nasdaq: RGDX) is engaged in the research and development of pharmacogenomic cancer diagnostic tests based on its proprietary and patented technologies. RGI’s technologies enable extraction and analysis of genetic information from genes derived from tumor samples stored as formalin-fixed and paraffin-embedded specimens. In addition to diagnostic testing services, RGI generates revenue from the sales of its proprietary analytical pharmacogenomic testing services of clinical trial specimens to the pharmaceutical industry. The Company was founded in 1999 and its principal headquarters are located in Los Angeles, California. For more information, please visit www.responsegenetics.com.

Forward-Looking Statement Notice

Except for the historical information contained herein, this press release and the statements of representatives of RGI related thereto contain or may contain, among other things, certain forward-looking statements, within the meaning of the Private Securities Litigation Reform Act of 1995.

Such forward-looking statements involve significant risks and uncertainties. Such statements may include, without limitation, statements with respect to the Company’s plans, objectives, projections, expectations and intentions, such as the ability of the Company to analyze cancer samples, the potential for using the results of this research to develop diagnostic tests for cancer, the usefulness of genetic information to tailor treatment to patients, the ability of the Company to expand its ResponseDX: Lung™ and ResponseDX: Colon™ test availability and the company to expand its sales force, and other statements identified by words such as “projects,” “may,” “could,” “would,” “should,” “believes,” “expects,” “anticipates,” “estimates,” “intends,” “plans” or similar expressions.

These statements are based upon the current beliefs and expectations of the Company’s management and are subject to significant risks and uncertainties, including those detailed in the Company’s filings with the Securities and Exchange Commission. Actual results, including, without limitation, actual sales results, if any, or the application of funds, may differ from those set forth in the forward-looking statements. These forward-looking statements involve certain risks and uncertainties that are subject to change based on various factors (many of which are beyond the Company’s control). The Company undertakes no obligation to publicly update forward-looking statements, whether because of new information, future events or otherwise, except as required by law.