ZP3 and ovarian neoplasm: Further supporting the contribution of overactivation of TGFBR1 in granulosa cells to ovarian tumorigenesis in the TGFBR1-CAG9Cre model, mice harboring TGFBR1CA and Zp3-Cre, which is expressed in growing oocytes, but not non-growing oocytes of primordial follicles [19], did not develop ovarian tumors, regardless of the parental origin of Cre transmission (Y. Gao and Q. Li, unpublished observation).