Expression of the cytokeratin marker CAM 5.2 in cervical neoplasia.

It has been suggested that cytokeratin CAM 5.2 is a useful marker to indicate malignant transformation and invasive potential in cervical neoplasia. In this study we examined normal ectocervical epithelium, endocervical squamous metaplasia, cervical intra-epithelial neoplasia (CIN) and invasive carcinoma by the indirect immunoperoxidase method using commercially available CAM 5.2. Positive staining was seen in 12 of 42 (28%) invasive carcinomas and in 2 of 26 specimens of CIN III. No positive staining was observed in any case of CIN II (22 specimens), CIN I (19), squamous metaplasia (21) or normal ectocervical epithelium (16). These results suggest that although CAM 5.2 expression is found in only 28% of cervical squamous carcinoma, it is highly specific for malignant transformation of cervical squamous epithelium. In view of its potential diagnostic value in doubtful cases of CIN III and squamous cell carcinoma, the specificity and sensitivity of CAM 5.2 expression in cervical neoplasia need to be examined in other laboratories under various processing schedules.