USP1 and ovarian neoplasm: Cysteine protease DUBs consist of four major subfamily groups: (1) the Ub-specific protease (USP/UBP), the largest superfamily (various USPs, such as USP1, USP2, and so on) of DUBs; (2) the ovarian tumor (OTU) superfamily; (3) the Machado–Josephin domain (MJD) superfamily; and (4) the Ub C-terminal hydrolase (UCH) superfamily [13,14].