MAP3K7 and hepatocellular carcinoma: To decipher the oncogenic role of the fetal TAK1 variant and the underlying mechanism, we depleted endogenous TAK1 expression in HCC cells with shRNA targeting both variants (shTAK1 cells) and then stably transfected TAK1_ΔE12 (fetal variant) and TAK1_FL (adult variant) into shTAK1 cells.