Equity Group Investments leads round, joined by Cross Creek Capital and Stephens Capital Partners; Matt Zell named to Board of Directors

AUSTIN, TX (October 15, 2007) — Rules-Based Medicine, Inc. (RBM), the leading multiplexed biomarker testing laboratory, announced today that it has raised $25 million in private financing. Equity Group Investments LLC (EGI), an investment fund founded by Sam Zell, led the Series A investment round. EGI is joined by Cross Creek Capital, the private equity affiliate of Wasatch Advisors, Inc. and Stephens Capital Partners. The financing will provide growth capital, debt repayment, and funding for acquisitions and investments to discover and validate biomarkers for medical diagnostics. In conjunction with the funding, RBM also announced that Matt Zell, managing director of EGI, has joined its Board of Directors.

“RBM is fortunate to welcome this prestigious group of highly successful investors into our capital structure. With this funding in hand we can continue our aggressive growth in the clinical trials services business, while accelerating our development of diagnostic services and kits,” said T. Craig Benson, chief executive officer of Rules-Based Medicine. “We are extremely pleased to have Matt join our board. His strategic perspective and vast experience in building companies and creating value will be a tremendous resource for RBM.”

RBM’s biomarker testing services business has seen a dramatic increase in adoption by pharmaceutical, biotechnology and consumer products companies. Due to the escalating demands by regulatory agencies to make pharmaceutical drug development safer, biomarker testing is now integral to pre-clinical and clinical research. Because biomarker testing can be economically outsourced via RBM’s RodentMAP™ and HumanMAP® services, RBM has become an essential tool for drug development companies worldwide as they bring new and safer drugs to market quicker and more cost-effectively. Biomarkers are also playing a larger role in diagnosing medical conditions and diseases, increasingly as companions to new therapeutics, presenting an emerging growth area for RBM.

“Rules-Based Medicine has secured a leadership position in the biomarker industry with its multiplexed approach, and its versatile and experienced management team,” said Matt Zell, managing director of EGI. “We look forward to working with RBM to maximize its many strategic opportunities.”

“RBM has built a scalable operating platform with a history of excellent performance,” said Karey Barker, managing director for Cross Creek Capital. “We are excited to contribute to RBM’s rapid growth in the international multiplexed biomarker field.”

Stephens Inc. served as the Company’s exclusive placement agent and financial advisor for this offering, the first since the formation of RBM in 2002.

About Wasatch Advisors®
Founded in 1975, Salt Lake City based Wasatch Advisors is an employee-owned investment adviser with approximately $9 billion under management. Wasatch Advisors is the investment adviser to Wasatch Funds®, a family of no-load mutual funds, as well as separately managed institutional and individual portfolios. Wasatch Advisors pursues a disciplined approach to investing, focused on bottom-up, fundamental analysis vetted through a uniquely collaborative Multiple Eyes™ process to leverage the knowledge and skill of the entire Wasatch Advisors research team.

About Cross Creek Capital™
Wasatch Advisors’ private equity affiliate, Cross Creek Capital, is a venture capital fund focused on late-stage private equity investments in what it believes are the best-of-breed public companies of the future. Wasatch Advisors’ experience in evaluating small public companies gives it unique insight into evaluating late-stage private companies. Cross Creek Capital leverages the knowledge and skill of the broader Wasatch Advisors research team in its investment decisions. More information is located at www.crosscreekcapital.com.

About Stephens Capital Partners
Stephens Capital Partners is the merchant banking affiliate of Stephens Inc., a full service investment banking firm headquartered in Little Rock, Arkansas. Stephens Capital Partners identifies opportunities to work with industry-leading management teams, providing public and private companies with capital for growth, recapitalizations, or leveraged buyouts. Stephens has a sixty year history of making private equity investments and a worldwide network of successful long-term partnerships. Stephens Capital Partners and Stephens Inc. are owned by Warren Stephens. More information is located at www.stephens.com.

About Rules-Based Medicine

Rules-Based Medicine (RBM) provides comprehensive protein biomarker products and services centered on its Multi-Analyte Profiling (MAP) technology. Its service platform (RodentMAP® and HumanMAP®) provides pre-clinical and clinical researchers with reproducible, quantitative, multiplexed immunoassay data for hundreds of proteins cost-effectively in multiple species, and from a small sample volume. The Company also offers innovative and proprietary ex vivo testing systems such as TruCulture™, the first fully-closed, reproducible whole blood culture system. RBM is actively developing multiplex diagnostic tests to detect the presence of complex diseases and conditions in areas of unmet medical need such as neuropsychiatry, nephrology, immunology and cardiology. More information about RBM is located at www.rbmmaps.com.