Molecular Biomarkers of Response to Cancer Immunotherapy

Abstract

Harnessing the immune system to advance cancer therapy has offered a new weapon in the quiver of clinical oncology. The lack of uniform, robust, or durable responses in many patients has necessitated the development of approaches for the accurate prediction of subgroups that are most likely to benefit from immunotherapy. This has led to the development and regulatory approval of predictive biomarkers, as well as associated companion diagnostics. Despite these strides, there still exists great heterogeneity in the choice of biomarkers, the laboratory assays that generate them, and their overall clinical utility. This article surveys broadly the predictive biomarkers of response to cancer immunotherapy, focusing on the biomarkers with current Food and Drug Administration (FDA) approval, and raising awareness of issues that may affect their broad applicability.

Keywords: Biomarkers; Immune checkpoint inhibitors; Immunotherapy; Microsatellite instability; PD-L1; Tumor mutational burden.