PCDH19 and hepatocellular carcinoma: For instance, the methylation of PCDH19 predicted a poor prognosis of hepatocellular carcinoma [31]; the methylation of DFNA5 showed strong potential as a prognostic biomarker for breast cancer; and the signature of CXCL11 combined with HMGA2 could precisely predict the OS of patients with high-grade serous ovarian cancer [30].