The correlation of protein peroxidation with morphological changes in experimental oestradiol-induced carcinogenesis.

Oestradiol-induced male Syrian hamster carcinogenesis is a well-known experimental model of human cancer of the breast, ovary and uterus. The pathomechanism postulated in this model is 4-hydroxylation of oestradiol and further free radical formation. The same process is suspected in human breast cancer. Dynamic changes in protein peroxidation were reported during the tumour induction. In this paper we try to correlate the protein peroxidation markers with the histopathological progression of the changes. The biochemical and histopathological evaluations were performed after 1, 3, 6 and 9 months of the hormone exposition. Significant protein peroxidation was observed as soon as after 1 month and increased further until the 6th month. After 9 months however, it was not significantly different from the control. The discrete histopathological changes after 1 month, progressed into tubular and interstitial hyperplasias after 3 and 6 months. After 9 months several dysplastic areas, sometimes with features of carcinoma in situ, were observed. The severe 9-month histopathological changes did not correlate with the protein peroxidation.