PIWIL1 and endometrial cancer: In this study, we further confirm that the expression of PIWIL1 in different endometrial cancer cell lines is associated with methylation status of the PIWIL1 promoter (Fig. 6), indicating that the reactivation of PIWIL1 in endometrial cancer may be associated with cancer-linked hypomethylation of the PIWIL1 promoter.