Immune Oncology Biomarkers in Lung Cancer: an Overview

Lung cancer is still the first cause of cancer-related deaths worldwide. The development of immune checkpoint inhibitors (ICI) has drastically changed the prognosis of some patients, but the rate of long responders does not exceed 20%. Moreover, ICIs are not adverse events-free and remain expensive. Therefore, predictive biomarkers of long-term benefit to ICI are required.

The two main fields being evaluated currently are PD-L1 expression and tumor mutational burden (TMB). The first one is the only one used in routine practice, and the second is being evaluated in phase 3 clinical trials. In addition, other biomarkers are being assessed as complex signatures, tumor-infiltrated lymphocytes, T cell receptor repertoire, or molecular profiling. The aim of this review is to summarize the current validated or promising biomarkers in lung cancer which could help to better select patients who will respond to ICI.