Spotlight on tumor mutational burden in patients with non-small cell lung carcinoma

In the last recent years, immune checkpoint inhibitors directed against programmed cell death-1 (PD-1) and its ligand programmed death-ligand 1 (PD-L1), have strongly changed the treatment paradigm of patients with non-small cell lung cancer (NSCLC). After initial clinical trials demonstrated improved outcome with these agents in patients with advanced or metastatic NSCLC, immunotherapy now has demonstrated survival advantage in some patients with early-stage NSCLC (1,2). Recent data suggest that combining these agents with chemotherapy or other immune checkpoint inhibitors may improve survival in patients with metastatic NSCLC compared to chemotherapy alone (3). However, the anti-PD-1/PD-L1 inhibitors have demonstrated highly durable responses in only a minority of patients. The modest impact of PD-L1 tumor expression to identify predictors of response to these agents has prompted the search for additional predictive biomarkers to better select patients who will benefit from immunotherapy (4)