TMPRSS2 and melanoma: NID1 has been shown to activate the ERK/MAPK signaling pathway to promote EMT and chemoresistance.[22] The functional capacity of NID1 in cancer metastasis has been revealed in breast, melanoma, ovarian, and endometrial cancers.[22, 23, 24] In contrast, TMPRSS2‐induced invasion of prostate cancer cells has been shown to be mediated by NID1 degradation.[39] NID1 secreted from endothelial cells inhibits breast cancer cell migration.[40] Despite the evidence implicating the complex roles of NID1 in different cancers, its involvement in HCC remains unclear.