IMMUNOHISTOCHEMICAL STAINING FOR KI-67 ANTIGEN, CARCINOEMBRYONIC ANTIGEN, AND P53 IN THE DIFFERENTIAL-DIAGNOSIS OF GLANDULAR LESIONS OF THECERVIX

Cytoplasmic carcinoembryonic antigen (CEA) positivity assists in the d istinction of benign and malignant glandular lesions of the cervix, bu t some cases remain problematic. The accumulation of p53 protein and a n increased proliferative index, as measured by the expression of Ki-6 7 antigen, have not been used as adjuncts to the diagnosis of these le sions. Immunohistochemical stains for CEA, p53 protein, and Ki-67 anti gen were performed on 31 formalin-fixed, paraffin-embedded endocervica l lesions including invasive adenocarcinoma, adenocarcinoma in situ, a denoma malignum, tunnel clusters, florid microglandular hyperplasia, m esonephric remnants, florid glandular hyperplasia, atypical glandular hyperplasia, and normal controls. Ki-67 antigen expression was quantit ated as negligible, low, moderate, or high on the basis of the percent age (<5%, 5-10%, 11-40%, >40%, respectively) of glandular nuclei that were positive with MIB-1 antibody. Strong staining of more than 10% of the glandular epithelial nuclei was interpreted as positive for p53 p rotein overexpression. CEA. positivity was determined by either diffus e or focal cytoplasmic staining of columnar epithelial cells equalling glycocalyceal staining in intensity. The combination of CEA positivit y and a moderate-to-high proliferative index was limited to cases of i nvasive adenocarcinoma, adenoma malignum, and adenocarcinoma in situ, as compared with benign glandular lesions (P = 0.005). A high Ki-67 pr oliferative index and/or CEA. positivity were features of malignant le sions rather than benign mimickers; there were no false positives or f alse negatives. Similarly, only malignant neoplasms shared a combinati on of p53 overexpression and CEA positivity (P = 0.043). The combinati on of cytoplasmic CEA positivity in glandular cells and a moderate-to- high Ki-67 proliferative index is diagnostic of malignancy in endocerv ical lesions, With the exception of florid microglandular hyperplasia, p53 expression is only seen in neoplastic lesions of the endocervix A n immunohistochemical battery consisting of MIB-1 (Ki-67), p53 protein , and CEA is useful in discriminating between benign and malignant end ocervical lesions.