The tumor suppressor protein p53 is a well-known regulator of p21 and Bcl-2 expressions.20, 21 The transcriptional activity of p53 can be regulated by post-translational modifications such as phosphorylation, acetylation and methylation.10, 22 Recent study showed that KDM3A inhibits p53 transcriptional activity by demethylating p53-K372me1 in breast cancer cells to represses apoptotic gene expression.23 Therefore, we hypothesized that KDM3A may influence p21 and Bcl-2 expressions by demethylating p53-K372me1 in ovarian cancer. This evidence concerns the gene CDKN1A and breast carcinoma.