ICOS and neoplasm: Interestingly, we found that engagement of FcγRs by anti-CTLA-4 antibodies is required for upregulation of the Th1-associated transcription factor Tbet in tumor-infiltrating effector CD4+ T cells, suggesting that factors derived from FcγR-expressing cells could be important for the maturation and function of Tbet+ICOS+ Th1-like CD4+ T cells.