The odds of immunotherapy success

Cancer immunotherapy has advanced to the forefront of molecular medicine as a consequence of the success of monoclonal antibodies (mAbs) that block immune checkpoints. Such antibodies, like ipilimumab, reverse cancer-induced immunosuppression and induce durable therapeutic responses in certain cancer patients (1). However, because only some patients respond to checkpoint blockade therapy, there is a need for reliable biomarkers that identify individuals most likely to respond to such treatment. On page 207 of this issue, Van Allen et al. (2) report the genomic analyses of tumors from 110 melanoma patients prior to ipilimumab therapy. The study not only validates features of responsive melanomas suggested in smaller-scale analyses, but also refutes claims that associate responsiveness to ipilimumab with tumor antigens that show putative similarities to microbial proteins (3).