Emerging biomarkers as predictors to anti-PD1/PD-L1 therapies in advanced melanoma

Recent advances in the field of cancer immunotherapy have resulted in a surge of new therapies for patients spanning multiple cancer indications. In melanoma alone, several immunotherapies have emerged as promising agents to tackle the aggressive, often refractory disease in the advanced/metastatic setting. The Programmed Cell Death pathway, from which anti-PD-1 and anti-PD-L1 therapies were developed, has shown immense promise. Given the marked success of the PD-1/PD-L1 immunotherapies, several targets have emerged as promising biomarkers, including PD-L1 tumor expression, tumor-infiltrating T-cell markers, dendritic cell markers, TCR sequencing, neoantigens and peripheral blood markers. Highlighted in this review, we examine the recent efforts to identify robust and reliable biomarkers as predictors of response to anti-PD-1/PD-L1 immune checkpoint inhibitors.