PALO ALTO — South San Francisco’s Crescendo Bioscience Inc., a maker of rheumatoid arthritis tests, and a Palo Alto team from Cooley hit a high note on the company’s $270 million acquisition by Myriad Genetics Inc. Salt Lake City-based Myriad, a molecular diagnostic company that last year was at the center of a high-profile Supreme Court patent case, tapped Mintz, Levin, Cohn, Ferris, Glovsky and Popeo of Boston for legal counsel.

The companies announced the all-cash transaction Wednesday, and the two have a history of collaboration. In September 2011, Myriad and Crescendo had inked a $25 million agreement with a three-year option to purchase, a practice that’s on the rise these days. That early investment will mean that Myriad’s current out-of-pocket expense is reduced to $245 million.