Summary
p53 mutations are known to occur frequently in human cancers where they are considered to be an important event in the step-wise progression towards malignant transformation. It is therefore interesting to compare p53 expression in the uterine cervix for non-neoplastic/metaplastic squamous epithelium, cervical intraepithelial neoplasia (CIN) and invasive squamous cell carcinoma. One hundred and nineteen biopsied and resected specimens of the uterine cervix were stained with an anti-human p53 protein monoclonal antibody by the streptavidin-biotin immunoperoxidase method. Histologically these could be categorized into non-neoplastic/dysplastic conditions, including condyloma (34 cases), CIN 1-3 (66 cases) and invasive squamous cell carcinoma (19 cases). Fifty eight per cent (11/19) of the invasive squamous cell carcinomas and 11% (7/66) of the CIN stained positively for p53. Except for 3 cases of invasive squamous cell carcinoma, there was only sporadic intranuclear staining of less than 5% of the cells. No staining was observed in all non-neoplastic/metaplastic squamous epithelial cells. The pattern of p53 staining is significantly different for all 3 categories. However it is undetermined as to whether the positive immunoperoxidase staining is a direct consequence of p53 gene mutation or otherwise.