Telomerase expression in normal epithelium, reactive atypia, squamous dysplasia, and squamous cell carcinoma of the uterine cervix.

Telomerase activity has been detected in a broad range of human malignant neoplasms, and its expression may represent an essential step in the malignant transformation of tissues; however, the expression of telomerase in premalignant lesions remains relatively unexplored. We tested tissue sections of cervical squamous cell carcinomas and squamous intraepithelial lesions, samples of benign reactive atypia, and normal cervical mucosa from hysterectomy and cone biopsy specimens for the expression of telomerase. Mirror-image sections from each sample were paraffin embedded and processed for histologic analysis. The test samples of cervical tissue were crushed under liquid nitrogen, and telomerase activity was determined by the telomeric repeat amplification protocol. Telomerase activity was detected in 18 of 18 cases (100%) of invasive squamous cell carcinoma. Twenty-five of 26 samples (96%) of high-grade squamous intraepithelial lesion also tested positively for telomerase activity, including 10 of 10 samples of moderate dysplasia, 12 of 13 samples of severe dysplasia, and 3 of 3 samples of carcinoma in situ. Telomerase activity was detected in 14 of 25 samples (56%) of low-grade squamous intraepithelial lesion and in 10 of 18 samples (56%) of reactive atypia but was detected in only 9 of 50 samples (18%) of histologically normal cervical mucosa. These results suggest that telomerase expression may be a marker of premalignant and malignant squamous cell lesions of the uterine cervix, although it is also expressed in a high proportion of cases of reactive atypia.