When we compared those genes with methylated promoters in samples of OCCA with and without endometriosis, only CACNA1A had a significantly higher promoter methylation status in OCCA samples without endometriosis (47.2%, 17/36) compared to those associated with endometriosis (0%, 0/8) (p = 0.013). The gene discussed is CACNA1A; the disease is endometriosis.