To determine whether forced expression of BMAL1 in BMAL1-deficient, HNF4α-positive hepatoblastoma and HCC impairs tumor growth, AML12, HepG2, Huh7, and SNU449 cells were transfected with an expression vector for BMAL1 and analyzed for growth and viability. The gene discussed is BMAL1; the disease is hepatocellular carcinoma.