SAN FRANCISCO — Even in a business known for promising miracles, it’s unusual for a three-year-old start-up that has yet to turn a profit to draw high-profile backers such as Microsoft Corp. founder Bill Gates and Russian billionaire Yuri Milner.

But such is the case with Foundation Medicine Inc., a Cambridge biotechnology company using genomics data and DNA sequencing to help doctors pinpoint treatments for cancer patients. Foundation Medicine had a kind of coming-out party here this week at the annual J.P. Morgan Healthcare Conference, the life sciences industry’s premier gathering of investors.