Veillonella and Streptococcus are associated with aging of the gut microbiota and affect the efficacy of immune checkpoint inhibitors

The rapid increase in the number of elderly patients with cancer necessitates treatment strategies based on the effects of aging because of drastic side effects of cytotoxic anticancer agents. Immune checkpoint inhibitors (ICIs) are relatively less toxic and can be easily administered to vulnerable and aged patients suffering from cancer. The diversity of gut microbiota and specific bacteria affects the efficacy and safety of ICIs. Therefore, this study aimed to assess the effect of aging on gut microbiota that play crucial roles in determining antitumor efficacy of drugs.