Immunostaining of histological sections of livers of rats with p53 antibodies. A, 3 months old control rats B, 3 months old quercetin-treated rats; C, 30 months old saline-treated rats; D, 30 months old quercetin-treated rats. Note the rarity of p53 expressions in A and B then the increase in its expression in C (arrows) then the rare of its expression in D.