TGFBR1 and ovarian neoplasm: To substantiate our findings and determine whether constitutive activation of TGFBR1 in the granulosa cells contributes to the ovarian tumor phenotype, we generated two complementary mouse models that expressed TGFBR1CA under the control of cytochrome P450 family 19-Cre (Cyp19-Cre) using Tg(CYP19A1-cre)1Jri mice, restricting Cre activity to the granulosa cells of antral follicles (Figure S1E), particularly those at late follicular stages [37].