Characteristics of studies included in the study characteristics of included studies.

BOT: benign ovarian tissues AT: adjacent tissues; NT: normal ovarian tissues of cancer-free patients or healthy people; NA: not available; MSP: methylation-specific polymerase chain reaction; MS-MLPA: methylation-specific multiplex ligation-dependent probe amplification; BSP: bisulfite sequencing PCR; M: RASSF1A methylated; U: RASSF1A unmethylated.