The FOXL2 gene resides on chromosome band 3q22.3 and encodes forkhead box protein L2, a forkhead-winged helix family transcription factor that is expressed in the eyelid and gonad during embryogenesis and actively maintains ovarian follicles during adulthood. A somatic missense mutation in FOXL2 (p.C134W; c.402C>G) is identified in 97% of adult granulosa cell tumor, and absent in other ovarian cancers. The prognosis and target treatment in regard of FOXL2 mutation is unknown.