Animal models for the preneoplastic lesions of the prostate.

OBJECTIVES

Reliable and adequate animal models are required, not only for investigation of etiology, pathogenesis, and treatment of prostate cancer, but also for chemoprevention of prostatic carcinogenesis.

METHODS

Animal models for the study of premalignant changes in the prostate are reviewed in the paper, with specific reference to the neonatally estrogenized mouse model.

RESULTS

Neonatal treatment of newborn Han:NMRI mice with synthetic non-steroidal estrogen, diethylstilbestrol (DES; 2 micrograms/pup on days 1-3 after birth) promoted hyperplastic and dysplastic changes in the periurethral region of the prostate at the age of 9-18 months. Dietary soy partially inhibited the development of prostatic dysplasia in these neonatally estrogenized animals, which may be due to phytoestrogens contained in soy-rich food.

CONCLUSION

Prostatic cancer and its possible precursors develop spontaneously, or can be induced by different chemical and hormonal manipulations in certain animal species and strains. Neonatal estrogenization of the mouse results in prostatic dysplasia, which can be partially prevented by dietary soy. There are morphological similarities between human prostatic intraepithelial neoplasia (PIN) and dysplastic changes in rodent prostates, but more data is needed before these dysplastic lesions can be considered equivalent to human PIN.