PD-L1 in melanoma: facts and myths.

The use of monoclonal antibodies that block immunologic checkpoints that would otherwise mediate the adaptive immune resistance have paved the way in cancer treatment. There is evidence that blocking the PD-1/PD-L1 axis is a strategy of overriding importance in the treatment of patients with metastatic melanoma and other solid malignancies, some of which (NSCLC, colorectal cancer, renal cell cancer, head and neck cancer) were not considered to be 'immune-responsive' diseases until recently. In this perspective article, the biological and clinical relevance of PD-L1 is summarized in the context of the immune checkpoint inhibitors as a therapeutic strategy in metastatic melanoma patients.