USP1 and cholangiocarcinoma: Interestingly, although previous research has identified other USP1 deubiquitination targets as pro-oncogenic, including KPNA2 in breast cancer metastasis [23] and RPS16 in hepatocellular carcinoma [30], these were not identified as USP1 substrates in our CCA model, suggesting that USP1 may serve different functions in different cancer types.