Our findings were consistent with reports showing that the ERK1/2 pathway is activated in ovarian cysts in PKBβ-knockout mice, a PCOS-like mouse model24 and that the ERK pathway inhibits StAR expression and consequent progesterone synthesis in rat granulosa cell-derived cell lines and in luteinized human granulosa cells25, 26. Here, MAPK3 is linked to polycystic ovary syndrome.