CTLA4 and sarcoma: Similarly, modulation of CTLA-4 efficacy in MCA205 sarcoma mouse models and patients with metastatic melanoma and non-small cell lung carcinoma were found to be dependent on the presence of B. fragilis or B. thetaiotaomicron influencing antitumor response through IL-2 dependent Th1 immunity, while simultaneously limiting anti-CTLA-4-mediated intestinal adverse effects [100] (Fig. 2).