CYP11A1 and neoplasm: In the B16-F10 melanoma and the orthotopic EO771 breast cancer models in mice, Mahata et al. reported that interleukins commonly found in tumor cells and their environment, such as IL-4, promote Cyp11a1 upregulation and an increase in pregnenolone synthesis in tumor-infiltrating immunosuppressive Th2 lymphocytes.