The use of an immunocytochemical double-labeling staining can display the distribution of Bcl-2/Ki-67 cells in endometrial adenocarcinomas as well as in normal endometrium.

BACKGROUND: Endometrial adenocarcinoma is the most common gynecologic malignancy and is the fifth most frequently diagnosed cancer in women. The objective of the present study was to determine the expression of a proliferation marker, Ki-67 and an apoptosis inhibitor, Bcl-2, by double-label staining in endometrial adenocarcinomas and in normal endometrium samples, to evaluate the differences in the immunocytochemical expression of Ki-67 and Bcl-2, and finally to correlate the results with tumor grade and stage.
METHODS: This study was carried on 270 endometrial samples, collected during a 27 month period, freshly resected from women who underwent total abdominal hysterectomy.
RESULTS: Ki-67 and Bcl-2 expressions were studied by immunocytochemistry. Bcl-2 expression was strong and homogeneous in normal (proliferative, secretory and atrophic) endometrium and more frequent in low-grade endometrioid carcinomas. Completely negative staining of Bcl-2 was found to be strictly related to high-grade endometrioid carcinomas. Ki-67 expression was higher in patients with high-grade endometrioid carcinomas. Proliferative endometrium showed inconclusive Ki-67 expression levels and in the secretory endometrium Ki-67 positive cells were remarkably diminished and even disappeared. Completely negative staining of Ki-67 was found to be strictly related to atrophic endometrium.
CONCLUSIONS: Immunocytochemical double-label staining can be used to display the distribution of Bcl-2 and Ki-67 cells in endometrioid carcinomas as well as normal endometrium, and, in addition to cytomorphologic features, contributes to its accurate diagnosis.