The effects of commercial whole milk on the prostate carcinogenesis in rats with or without induction by 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine

Prostate cancer has become the most common male cancer in Western countries and the incidence of this disease is increasing steadily in developing countries including China. The aim of the present study was to determine whether milk consumption promotes the development of prostate carcinogenesis in rats since milk consumption is considered to be a risk factor in some epidemiological studies. In the present study, we compared the prostate carcinogenesis in rats fed on commercial whole milk and artificial milk with or without induction by amino-1-methyl-6-phenylimidazo[4,5b]pyridine (PhIP). The atrophic changes became more serious in the ventral prostate in the milk groups with or without PhIP administration than in the corresponding artificial milk groups. In the ventral prostate, the incidence of prostatic intraepithelial neoplasia (PIN) also was significantly higher in the milk group than in the artificial milk group irrespective of PhIP administration. The rats given PhIP, either fed on milk or artificial milk, showed significantly higher incidences of PIN and adenocarcinoma in the ventral prostate, and dysplasia in the seminal vesicle. The present study suggests that commercial whole milk is likely to promote the development of prostate, especially ventral prostate, carcinogenesis in rats.