Figure 3.

Treatment with the differentiating agent PPZ does not induce p53 expression. PPZ induces morphological and functional differentiation of the mammary gland but is ineffective in offering protection from MNU-induced carcinogenesis. Rats received one injection of PPZ (s.c, 0.5 mg/100 g of body weight) five times a week for 3 weeks. Control animals received one injection of 0.03 N HCl five times a week for 3 weeks. Glands were allowed to involute for 28 days and then collected for immunohistochemical staining of p53. (A and B) AMV, 97 days; (C and D) PPZ-treated, 97 days.