USP4 and cancer: The USPs family is the largest and most important DUB family, and many of these elements are involved in the occurrence and development of multiple cancers, such as USP1, USP4, USP7, USP22, and USP28, which promote or inhibit the development and progression of colorectal, breast, and hepatocellular carcinomas via deubiquitining the hub genes of cancer-related signaling pathways [10, 11].