P53 PROTEIN EXPRESSION IN PUTATIVE PRECURSOR LESIONS OF EPITHELIAL OVARIAN-CANCER

p53 protein expression has been studied in epithelial inclusion cysts adjacent to and contralateral to serous carcinoma of the ovary and com pared to epithelial inclusion cysts associated with borderline tumours and in normal ovaries. Atypia was found in epithelial inclusion cysts in eight of the thirteen advanced (stage III) serous ovarian carcinom as. Of these eight with atypical epithelial inclusion cysts, five show ed immunoreactivity for p53, In the borderline tumours and normal ovar ies no atypia in such cysts was found, p53 expression was also seen mo re frequently in surface epithelium associated with ovarian serous ade nocarcinoma (ten of 13) than in normal ovaries (one of 13). We postula te that focal areas of atypia (ovarian intra-epithelial neoplasia) in epithelial inclusion cysts are the precursors of ovarian malignancy. I n some cases, at least, p53 protein expression may precede overt cytol ogical abnormalities.