Rational Discovery of Response Biomarkers: Candidate Prognostic Factors and Biomarkers for Checkpoint Inhibitor-Based Immunotherapy.

Immunotherapy with checkpoint inhibitor has been successfully applied in treatment for multiple cancer types, especially for patients at advanced stage. However, response rate of this promising therapy is low, thus requiring biomarkers for precise medication to reduce the ineffective treatment. With multiple retrospective clinical studies, more and more candidate prognostic factors have been identified with possible mechanic explanation, including the basic clinical characteristics (e.g., age and gender), molecular features (e.g., PD-L1 expression and tumor mutation burden). After validation in independent patient cohorts with large sample size, several markers have been approved as companion biomarkers. However, validation and combinations of all the possible candidate biomarkers are still challenging to predict the treatment outcomes. In this chapter, we will summarize and introduce the prognostic factors and biomarkers for checkpoint inhibitor-based immunotherapy.