Association of the gut microbiome with cancer immunotherapy.

Immune checkpoint inhibitors, programmed cell death-1- and cytotoxic T-lymphocyte-associated protein 4-based immunotherapy have remarkably improved survival with durable response for patients with multiple cancer type. The accurate predictors of response and toxicity to immunotherapy are still unclear and have been focused on the gut microbiome. The gut microbiome, which refers to the microorganisms and their genes, affects the host immunity both locally and systemically. Modulation of the gut microbiota alters the immune systems and affects the efficacy of immune checkpoint inhibitor. In this review, we investigate the evidence on the role of the microbiome in cancer patients and discuss the impact of microbiome on the efficacy of immune checkpoint inhibitors in cancer.