Apoptotic and Mitotic Index in Squamous Cell Carcinomas and Premalignant Lesions of the Uterine Cervix

Abstract

The aim of this study was to determine the frequency of apoptotic and mitotic cells in different grades of premalignant lesions and in different stages of squamous cell carcinoma (SCC) of the uterine cervix. The apoptotic and mitotic indices (A! and MI) of 55 H&E-stained sections of cervical intraepithelial neoplasia (CIN) and 30 SCCs were evaluated in light microscopy by a morphometric method. Twenty, 16, and 19 of 55 CIN cases were classified in CIN I, CIN II, and CIN III group, respectively. No apoptosis was observed in the normal epithelium next to the dysplastic mucosa. There was no statistically significant difference between CIN I and CIN II as well as CIN II and CIN III groups in terms of apoptotic and mitotic cell counts. Mitotic cell counts were found significantly higher in CIN III group when compared with CIN I and CIN II groups together. There was no statistically significant difference in the apoptotic and mitotic cell counts between nonkeratinizing and keratinizing types of SCC. In the SCC group, apoptotic cell counts did not show significant difference between tumor stages. But mitotic counts were significantly higher in advanced stage tumors. The SCC group showed significantly higher mitotic and apoptotic cell counts when compared with preneoplastic lesions. This study suggests that apoptotic function is not altered during progressive stages of dysplastic change in cervical epithelium, while proliferation is triggered only in late stages of dysplasia. Both apoptosis and mitosis are markedly increased in progression to malignancy in cervix epithelium. Mitotic cell counts may be helpful in predicting the extent of the disease in SCC. Resistance of cell death by apoptosis after invasion may accelerate the net growth of the tumor resulting in advanced disease.