Expression of telomerase RNA and caspase-3 in cervical intraepithelial lesions and invasive carcinoma

Kim, Young Ok; Lee, Chun June

Abstract

OBJECTIVE
Telomerase is an RNA-dependent DNA polymerase that synthesizes TTAGGG telomeric DNA. It has been detected in a variety of human malignancies, suggesting that it's activity may play a role in the tumorigenic process. Also, maintenance of telomerase activity is associated with increased resistance to apoptosis. Caspase-3 activation has been found to be essential components of the apoptotic pathway.
METHODS
To determine whether telomerase is involved in carcinogenesis of uterine cervix and to analyze the relationship between telomerase RNA and caspase-3 expression according to cervical cancer stage, we performed in situ hybridization for telomerase RNA and immunohistochemistry for caspase-3. The materials were 10 normal cervical tissues, 12 low grade intraepithelial lesions (LSIL), 20 high grade intraepithelial lesions (HSIL), 17 microinvasive carcinomas, 19 invasive carcinomas.
RESULTS
Telomerase RNA was weakly expressed in a few basal cells of normal squamous epithelium in uterine cervix. But, high expression rate was noted in squamous intraepithelial lesions and invasive carcinoma groups. Expression of telomerase RNA was demonstrated 5 (41.6%) of LSIL, 7 (35.0%) of HSIL, 6 (35.2%) of microinvasive carcinoma, and 11 (57.8%) of invasive carcinoma. Expression of caspase-3 was demonstrated 0% of LSIL, 13 (65.0%) of HSIL, 13 (76.4%) of microinvasive carcinoma, and 7 (36.8%) of invasive carcinoma. Relationship between telomerase RNA and caspase-3 expression according to stage was not seen. Telomerase RNA and caspase-3 expression showed weakly inverse correlation in invasive carcinoma group. Telomerase RNA and caspase-3 expression was not correlated with clinico-pathologic factors, including stage, tumor differentiation, invasion depth, and lymph node metastasis (p>0.05). But, weak correlation between telomerase RNA expression and tumor size was noted (p=0.05).
CONCLUSION
These data indicate telomerase might be involved in carcinogenesis of uterine cervix. Distinct relationship between telomerase RNA and caspase-3 was not seen according to stage. Expression of telomerase RNA and caspase-3 had no correlation with clinico-pathologic factors.