For example, butyric acid enhances the anti-tumor cytotoxic effect of CD8+T cells in vitro and promotes the anti-tumor effect of platinum-based chemotherapeutic drugs.51 Supplementation of probiotics alleviates 5-FU and platinum-related intestinal injuries and adverse reactions.105Lactobacillus supplementation during chemotherapy in CRC patients treated with 5-FU reduces mortality and improves gastrointestinal symptoms such as diarrhea.106 Furthermore, the gut microbiota modulates irinotecan’s metabolism and adverse effects. The gene discussed is CD8A; the disease is neoplasm.