For R-Smads, SMAD1 regulated COV434 cell (a human granulosa cell tumor-derived cell line) apoptosis [46], and SMAD5 suppressed human granulosa cell apoptosis via the FasL-Fas pathway [47,48], but SMAD8 has not been reported to regulate GC apoptosis. This evidence concerns the gene SMAD1 and granulosa cell tumor.