Objective: To investigate the telomerase activity in cervical tissues and exfoliated cells in patients with cervical intraepithelial neoplasia (CIN) and cervical carcinoma, and to study the correlation between telomerase activity and koilocytosis classification and between telomorase activity and human papillomavirus (HPV) infection.
Methods: Telomeric repeat amplification protocol (TRAP) was used to determine the telomerase activity in cervical tissues and exfoliated cells in 24 women with normal cervix, 34 patients with cervitis, 78 patients with CIN and 16 patients with cervical carcinoma. The patients with CIN were classified into 3 subgroups according to the abnormality of cervical cells (31 CIN(1) cases, 25 CIN(2) cases and 22 CIN(3) cases). The presence and classification of koilocyte in cervical tissues was examined by microscopy with double blind method. The telomerase activity in koilocytes of different types was investigated.
Results: The telomerase positive rate was 16.7% (4/24) in normal cervical tissue, 17.6% (6/34) in cervitis tissue, 51.6% (16/31) in CIN(1) tissue, 72.0% (18/25) in CIN(2) tissue, 86.4% (19/22) in CIN(3) tissue, and 100% (16/16) in cervical carcinoma tissue respectively. The telomerase positive rate in CIN cases was significantly higher than those in normal cervix and cervitis cases (all P < 0.01) and the telomerase positive rate was significantly higher in cervical carcinoma than in CIN (P < 0.01). It was also significantly higher in CIN(3) than in CIN(1) (P < 0.05), while no significant difference was found in the telomerase positive rate between normal cervix and cervitis, CIN(1) and CIN(2), and CIN(2) and CIN(3) (P > 0.05). No significant difference of telomerase positive rate was found between the cervical tissue and exfoliated cells in the same case too (P > 0.05). Koilocytes were found in sixty-four out of the 154 samples of cervical lesions. Among them koilocytes were found in 54 out of 94 samples of cervical cancer and CIN tissues (koilocytes of type I in 18 cases and type II in 36 cases). The telomerase positive rate was 100% in tissues of CIN and cervical carcinoma with type II koilocytosis, significantly higher than that in tissues with type I koilocytosis (66.7%, P < 0.05).
Conclusion: (1) Activation of telomerase is closely associated with progression of CIN and cervical carcinoma, and telomerase might be a useful marker for cervical carcinoma and CIN. (2) Cervical exfoliated cells may be used as the substitute of cervical tissues in determining telomerase activity. (3) Activation of telomerase is correlated with type II koilocytosis and HPV 16/18 infection.