Phase 2 trial identifies genetic dysfunction that makes many types of cancer vulnerable to an immunotherapy A team of researchers has identified a genetic malfunction that predicts the effectiveness of response to a groundbreaking immunotherapy. The results of their Phase 2 clinical trial reveal that, regardless of its tissue of origin, tumors whose cells are deficient in repairing mismatched DNA sequences--and so preventing mutations--are far more susceptible to the checkpoint inhibitor pembrolizumab than those that retain this ability....