E2F1 and liver cancer: We have previously shown that TRIB2 inhibition either through TRIB2 knockdown or via inhibition of an E2F1-TRIB2 regulatory loop results in perturbation of the cell cycle and cell death [18], and TRIB2 level was shown to be under the control of the β-TRCP ubiquitin E3 ligase in liver cancer cells [16].