Consistently, in the presence of cycloheximide (CHX, an inhibitor of protein translation), inhibition of USP8 promoted the degradation of endogenous FTL protein in human liver cancer cell line HepG2 (Figs. 1N and S2A) and overexpression of USP8 delayed the protein turnover of exogenous FTL protein in HEK 293T cells (Figs. 1O and S2B). This evidence concerns the gene FTL and liver cancer.