The current study examined variation in nine key genes involved in circadian rhythm regulation or their transcription (BMAL1, CRY2, CSNK1E, KLF10, NPAS2, PER3, REV1, SENP3, TIMELESS) as predictors of epithelial ovarian cancer risk, histopathologic subtype, and invasiveness. This evidence concerns the gene CRY2 and ovarian carcinoma.