Expression of Ki-67 in vulvar carcinoma and vulvar intraepithelial neoplasia III. Correlation with clinical prognostic factors

Objectives. In vulvar carcinoma, the expression of Ki-67 has been previousl y found to correlate with patient outcome. The objective of the study was t o determine whether a specific pattern of expression was associated with oc cult vulvar cancer in patients with vulvar intraepithelial neoplasia (VIN) III and whether patterns of Ki-67 expression correlated with other clinical prognostic factors. Methods. 19 women with only VIN III, 16 women with both vulvar cancer and V IN III, and 15 women with only vulvar cancer were identified. Immunostainin g, using a monoclonal antibody for Ki-67, was then performed on representat ive tissue blocks and slides were assessed for diffuse or localized pattern s of expression. For the patients with vulvar cancer, the type of staining was correlated with FIGO stage, tumor grade, lymph nodes status, and associ ated VIN III. Results. All 35 patients with VIN III exhibited a diffuse staining pattern. In the 31 patients with vulvar carcinoma, 11 (35%) expressed a diffuse sta ining pattern while 20 (65%) showed a localized pattern. Poorly differentia ted tumors were associated with a diffuse staining pattern (P = 0.013, RR 3 .59, CI 1.59-7.60). For vulvar carcinoma, there were no statistically signi ficant relationships between Ki-67 expression pattern and stage, associated VIN III, or lymph node involvement. Conclusion. VIN III, regardless of a concomitant vulvar cancer, always expr essed a diffuse pattern; thus Ki-67 staining was not useful as a marker for occult cancer. In women with vulvar carcinoma, however, a diffuse Ki-67 ex pression was significantly associated with poorly differentiated tumors. (C ) 2000 Academic Press.