USP39 and cancer: The importance of USP39 in cancer cell proliferation, survival, migration and resistance to chemotherapy has been reported in a wide variety of tumors beside CRC [121,122] and lung cancer [123], such as hepatocellular carcinoma [124,125,126], ovary carcinoma [127,128], osteosarcoma [129,130], glioma [131], melanoma [132], gastric [133] and pancreatic cancer [134] and renal cell carcinoma [135].