HNF4A and hepatocellular carcinoma: Staining of unsynchronized cells transfected with GFP or GFP-BMAL1 revealed an increase in cleaved caspase 3 in BMAL1 overexpressing cells (Fig. 6e), suggesting that forced expression of the circadian protein BMAL1 in HNF4α-positive HCC inhibits tumor growth by inducing apoptosis, though additional BMAL1-mediated mechanisms may also contribute57,58.