Microbial butyrate boosts the antitumor cytotoxic CD8+ T cell response80,123 and further enhances the response to chemotherapy to suppress tumor progression.79 Elevated serum butyrate level in the oxaliplatin responder confirms this effect.79 Moreover, pentanoate and butyrate can also promote the anti-tumor activity of chimeric antigen receptor (CAR) T cells,80 thus enhancing the adoptive immunotherapy. The gene discussed is CD8A; the disease is neoplasm.