Pehub.com -- On-Q-Ity, a Waltham, Mass.-based cancer diagnostics company, has raised $5 million in additional Series A funding from Atlas Venture. This brings the round total to $26 million, including past investments from Mohr Davidow Ventures, Bessemer Venture Partners, Physic Ventures and Northgate Capital. On-Q-Ity was recently formed via the merger of two VC-backed companies: The DNA Repair Company and CELLective Diagnostics.