USP13 and hepatocellular carcinoma: Toll-like receptor 4 (TLR4), an essential sensor involved in carcinogenesis, is also a substrate of USP13, and TLR4/myeloid differentiation factor 88 (MyD88)/NF-κB pathway activation facilitates the proliferation, migration and invasion of HCC cells (Chen et al., 2008; Gao et al., 2020).