Relationship Between Telomerase And HPV16/18E6Protein In Cervical Lesions And Their Significance

Background and ObjectiveHuman papillomavirus (HPV) is one of the primary causes oftumorigenesis of cervical cancer. Generally, HPV gene integrates afterinfecting the host cells and its coding E6oncoprotein can directly or indirectlyactivate telomerase. Cells become immortalized via regulation of cell cycle andapoptosis by E6protein and transform into malignant cells. Human telomericreverse transcriptase (hTERT) and human telomeric RNA Component (hTERC)are crucial core components and subunits of telomerase. Telomerase activityprimarily depends on the expression of hTERT protein and hTERC gene. Toinvestigate the relationship among the expression of hTERT, HPV16/18E6protein and hTERC gene in cervical lesions, immunohistochemistry(SupervisionTM) was performed to detect the expression of hTERT andHPV16/18E6proteins, and amplification of hTERC was detected by fluorescentin situ hybridization (FISH). The aim of the current study was to analyze therelationship among hTERC gene, hTERT and HPV16/18E6proteins, and alsoto improve prognosis assessment of cervical precancerous lesions. Material and Methods1. The paraffin-embedded tissues of cervix were collected from PathologyDepartment of First Affiliated Hospital of Guangxi Medical University fromMay2008to July2013. Total of235samples were recruited, and divided into6groups including34cases of cervical inflammation (samples from hysterectomywith hysteromyoma and without any cervical neoplastic lesion),35cases of CIN(Cervical Intraepithelial Neoplasia) Ⅰ,23cases of CINⅡ,25cases of CINⅢ,101cases of squamous carcinoma and17cases of adenocarcinoma. The ageranged from21to73years old, with average of45.40years old. All the caseswere confirmed by the histological diagnosis.2. Immunohistochemistry (SupervisionTM) was performed to detect theexpression of hTERT and HPV16/18E6proteins on samples of differentcervical diseases.3. Amplification of hTERC gene was detected by using FISH in some cases.Results1. Expression of hTERT and HPV16/18E6protein.Immunohistochemical results showed that hTERT protein expressed innucleus and cytoplasm of epithelial cells. The expression ratio of hTERT proteinin the groups of cervical inflammation, CINⅠ, CINⅡ, CINⅢ, squamouscarcinoma and adenocarcinoma was17.65%,31.43%,69.57%,72.00%,78.22%,70.59%; significant differences were observed in different groups (P＜0.05).From the group of inflammation to squamous carcinoma, hTERT proteinexpression ratio increased with the deterioration of disease (P＜0.05).HPV16/18E6protein which expressed in cytoplasm of epithelial cells, theexpression ratio in aforementioned groups was11.76%,25.71%,47.83%,44.00%,60.40%,76.47%, respectively. There were significant differences indifferent groups of HPV16/18E6protein expression ratio (P＜0.05). From the group of inflammation to squamous carcinoma, HPV16/18E6protein expressionratio increased with the deterioration of disease (P＜0.05).2. The relationship between hTERT and HPV16/18E6proteinSeventy cases of hTERT and HPV16/18E6protein were negative, and88cases were positive. There were56cases with hTERT being positive whilenegative for HPV16/18E6protein, and21cases were negative for hTERT whilepositive for HPV16/18E6protein. A positive correlation was found between theexpression of hTERT and HPV16/18E6protein (P＜0.05).3. Amplification of hTERC geneFISH analysis was performed on112cervical specimens. The percentage ofsuccessful hybridization was89.29%(100/112). Both the numbers of greensignals which were control probes and orange signals which were hTERC genewere≤2in normal cells; the orange signals number was＞2in abnormal cells.The amplification ratio of hTERC gene in the groups of cervical inflammation,CINⅠ, CINⅡ, CINⅢ, squamous carcinoma and adenocarcinoma was0.00%,13.64%,73.33%,83.33%,100%,100%. The amplification rate of hTERCshowed significant differences in all groups (P＜0.05), and increasedaccordingly with escalating levels of dysplasia in the groups of inflammation,CIN and squamous carcinoma (P＜0.05). Most of inflammatoryspecimens showed two green (control probe) and two orange (hTERC probe)hybridization signals; the pattern of2:3which hTERC amplicated was graduallyincrease in CIN groups; signal patterns were more complicated in the groups ofsquamous carcinoma and adenocarcinoma, the signal patterns of green andorange were primary2:3、3:3、3:4, etc，and orange signals were clusters.4. The relationship between Amplification of hTERC and hTERT or HPV16/18E6protein. There was a positive correlation between the amplification of hTERC andexpression of hTERT protein (P＜0.05), as well as the amplification of hTERCgene and expression of HPV16/18E6protein(P＜0.05).ConclusionsThe expression of hTERT and HPV16/18E6protein increases with thedeterioration of cervical lesions, as well as the amplification of hTERC gene.They may serve as for early event of cervical caner, and might be a biomarker ofprognosis assessment of cervical precancerous lesions.