The detection of hTERC amplification using fluorescence in situ hybridization in the diagnosis and prognosis of cervical intraepithelial neoplasia: a case control study

Abstract

Background: Currently the routine non-invasive screening methods for cervical intraepithelial neoplasia (CIN) and cervical cancer are Thinprep cytology test (TCT) and human papillomavirus testing. However, both methods are limited by the high false positive and false negative rates and lack of association with patients' prognosis, especially for the early detection of pro-malignant CIN. The aim of the study was to investigate the role of genomic amplification of human telomerase gene (hTERC) in the diagnosis and prognosis of CIN.

Methods: The study group consisted of specimens of exfoliated cervical cells from 151 patients, including 27 with CIN I, 54 with CIN II/III, 17 with carcinoma in situ, and 28 with invasive squamous carcinoma, as well as 25 patients who were at 2-year follow-up after either Loop Electrosurgical Excision treatment (n = 11) or radical surgery (n = 14). hTERC amplification was detected by dual-color interphase fluorescence in situ hybridization (FISH), and the results were compared with TCT and histologic examination. The final diagnosis was determined by the pathological examination. The control group consisted of specimens of exfoliated cervical cells from 40 normal women.

Results: The percentage of cervical exfoliated cells with positive hTERC amplification and incidence rates of hTERC amplification were 9.2% ± 4.6% and 44.4% (12/27) respectively in patients with CIN I; 16.0% ± 14.4% and 85.1% (46/54) in patients with CIN II/III; 19.7% ± 13.3% and 88.3% (15 /17) in patients with carcinoma in situ; 47.0% ± 25.2% and 100% (28/28)in patients with invasive squamous carcinoma. There was statistically significant difference between the control and study group (P <0.01), and between the patients with various diseases within the study group (P <0.05).

Conclusion: The detection of genomic amplification of hTERC using FISH is a non-invasive and effective approach for CIN.

Figure 1

Photographs of hTERC amplification using FISH in the normal cervix, CIN I, CIN III and cervical carcinoma. (A) Normal cervix. Among the normal cervical epithelial cells, there were two red and two green signals in nuclei during cell interphase. (B) CIN I. The hTERC amplification in heterogeneous cells was demonstrated as more than two red signals and no less than two green signals in the nucleus during cell interphase. The hTERC amplification test showed that the percentage of cells with more than two red signals was on average 9.2%. (C) CIN III. The hTERC amplification test showed that the percentage of cells with more than two red signals was on average 16.0%. (D) Cervical cacinoma. The hTERC amplification test showed that the percentage of cells with more than two red signals was on average 47.0%. hTERC, human telomerase mRNA component gene; FISH, fluorescence in situ hybridization; CIN, cervical intraepithelial neoplasia.