CDK4 and esophageal cancer: Lastly, for the three monotonically increasing genes with good biological relevance, CDK4, DNMT3B, and MAGEA4 to esophageal cancer, previous studies [47, 48] suggested the last two genes as oncogenes for esophageal cancer while another study [49] suggested CDK4 was underexpressed in the tumor samples of esophageal cancer.