T cell responses specific for B. Thetaiotaomicron or B. fragilis were associated with the efficacy of the CTLA-4 blockade, and the introduction of B. fragilis into germ-free mice sensitized to murine neoplasms to CTLA-4 treatment, which was ineffective in germ-free animals [142,143,144]. This evidence concerns the gene CTLA4 and neoplasm.