Mara Aspinall, the founder and former CEO of Waltham, MA-based On-Q-ity, has moved on to become president of Ventana Medical Systems, an Arizona-based division of healthcare giant Roche that focuses on cancer diagnostics. The appointment was announced in a press release today and is effective next month.

Aspinall is well known in the diagnostics world, having previously served as president of the genetic testing unit of Cambridge, MA-based Genzyme. On-Q-ity, which started in 2009, focuses on molecular diagnostics for cancer. The startup’s website still lists Aspinall as a founder and director, but makes no mention of a successor (or search for one) yet.