NEDD4 and cancer: NEDD4 E3 ligase family genes were distributed heterogeneously in various cancer types (Fig. 1A): NEDD4 E3 ligase family genes presented high expression in some tumors including pancreas cancer, esophagus cancer, gastric cancer and colon cancer; while NEDD4 E3 ligase family genes showed low expression in certain tumors of kidney, thyroid, and testis cancer.