CYP11A1 and neoplasm: To determine whether intratumoral macrophages were M1 or M2 type, we purified tumor-infiltrating macrophages and analyzed mRNA expression of the M2-macrophage signature genes Arg1 and Tgfβ1. In tumor-infiltrating macrophages from Cyp11a1 cKO mice, Arg1 and Tgfβ1 mRNA expression was significantly reduced compared to the control mice, indicating fewer of the tumor-supporting M2 macrophages in the T cell-specific Cyp11a1 knockout mice (Fig. 6a).