Despite the negative regulatory effects of CDKN3 on CDK1 and CDK2, an oncogenic role for aberrant overexpression of CDKN3 has been implicated in numerous types of human cancer, including prostate cancer [37], gastric cancer [38], nasopharyngeal carcinoma [39], and esophageal cancer [40]. This evidence concerns the gene CDK2 and esophageal cancer.