To investigate whether the enhanced or suppressed expression of HNF4α can be involved in hepatic polarization, the HNF4α expression in HepG2 cells was manipulated by infection with Ad-HNF4α or LV-HNF4α and Ad-Mock or LV-Mock as the blank control, of which the effects were verified at both the mRNA and protein levels. The gene discussed is HNF4A; the disease is infection.