| Cervical cancer (CC) ranks the second most common cancer among women worldwide. Approximately 80% of CC cases in the world occur in developing countries. The pathogenesis of uterine cervical cancer is not fully understood. In China, there are almost 110,000 new cases of CC and 20,000 to 30.000 deaths annually. It has been well established that human papillomaviruses (HPV) is a necessary but insufficient cause of CC and its precursors (cervical intraepithelial neoplasia, CIN). More than 100 genotypes have been identified, among which 40 types are associated with genital infection and classified into high-risk (HR-HPV), probable high-risk and low-risk (LR-HPV) categories. HR-HPV types include HPV 16,18,31,33,35,39,45,51,52, 56,58,59,68,73 and 82; probable high-risk types include HPV 26,53 and 66; LR-HPV types include HPV 6,11,40,42,43,44,54,61,70,72,81 and CP6108.Geographic variation in the prevalence and distribution of HPV genotypes had been reported to exist between countries, even different regions in the same country. Furthermore, the effect of prophylactic virus-like particle (VLP) HPV vaccine is type specific. Therefore, updated information on type-specific HPV prevalence and distribution in a given population is necessary for the development and evaluation of effective HPV vaccines, cervical cancer screening, as well as following-up of women treated conservatively for a cervical lesion. Presently, few studies have been performed concerning the prevalence and distribution of HPV genotypes in women with cervical lesions from Liaoning Province, China.Approximately 80% of women will become infected with HPV during their life time but only minority of them will develop an HPV-associated precursors or CC. Thus, additional risk factors are needed which can be environmental, host-or virus-related factors, such as HPV type, integration or viral load for progression to CC. HPV DNA can be found in cervical material in three forms:those are in episomal forms, integrated forms or mixed forms that contain both. Currently, an area of very active research interest is HR-HPV DNA integration into the host genome. The majority reported data on HPV integration were about the most common genotypes detected in the worldwide cases of CC, which were HPV 16 and 18. They were detected in approximately 50% and 20% of all CC cases worldwide respectively. Studies based on HPV type 18 positive clinical specimens showed that integration is virtually completed in high-grade lesions and invasive cancers. However, the results obtained from HPV 16 positive specimens are more diverse. Integration data on other HR-HPV types are very limited. A recent integration study about the five most common HR-HPV types (HPV types 16,18,31,33 and 45) revealed that the integration frequency of HR-HPV in cervical lesions were type-dependant. Besides, it has recently been demonstrated that the integration of HPV-16 genome does not invariably result in high levels of oncogene E6/E7 expression. Therefore, further investigation about the role of HPV integration in cervical carcinogenesis is warranted.HPV58, though generally regarded as an uncommon type, has been found to exist with an unusually high prevalence in a few Chinese populations, including the population in Liaoning area. Most recently, it was reported HPV types 16,18 and 58 were the three leading HPV types found in CC samples from women living in Liaoning area, China. So far, a few was reported on HPV58 integration in different cervical lesions. Unlike results obtained from HPV 16 positive samples, data on HPV 18 integration in cervical lesions was accordant Therefore, cervical swabs specimens infected with HPV type 16 or 58 were collected in this survey.This study aimed to investigate the prevalence and type distribution of HPV infection in patient with cervical lesions confirmed histologically in Liaoning Province. HPV genotyping was performed using the newly introduced HPV GenoArray test (Hybrimax) on cervical swabs taken pre-operatively from 1444 women. They were selected from the patients referred to the Shengjing Hospital, China Medical University. They underwent voluntary cervical cancer screening in the department of Gynecology and Obstetrics of the above hospital. The majority of them were from urban.The association of HPV genotypes with the histological results were analyzed. In addition, we evaluated the accuracy of the HPV GenoArray test for the diagnosis of cervical neoplasm.Furthermore, multiple polymerase chain reactions (PCR) was performed to detect physical status of HPV types 16 or 58 in a series of cervical Liquid-based cytology (LBC) samples obtained from women with different cervical lesions, including 493 specimens with HPV 16 infection and 74 samples with HPV 58 infection. The role of HPV types 16 or 58 integration in cervical carcinogenesis was further analyzed by comparing their integration frequencies.Methods1. A total of 1444 cervical swabs from patients with cervical cancer (CC, N=134), cervical intraepithelial neoplasia (CIN)â…¡/â…¢(N=517), and CINâ… (N=180) were detected for HPV genotypes using the PGMY09/11 primer system and HPV GenoArray test (Hybriobio Ltd., Hong Kong). Age-matched samples of 613 women without cervical neoplasia were analyzed as control. The prevalence and distribution of HPV genotypes in uterine cervical lesions were analyzed from women living in Liaoning Province, China. In addition, The associations of individual HPV genotype infection with the severity of cervical lesions were evaluated.2. A total of 493 cervical Liquid-based cytological (LBC) samples from patients with cervical cancer (CC, N=103), cervical intraepithelial neoplasia (CIN)â…¡/â…¢(N=351), CINâ… (N=34), and chronic cervicitis (N=65) were detected E2 and E6 genes of HPV type 16 using multiple polymerase chain reaction (PCR). Additionally,40 samples from women without cervical neoplasia were analyzed as control. All of the specimens were infected with HPV type 16. E2/E6 ratio was used to evaluate the physical status of HPV DNA in host cell genome. The correlations between the prevalence of HPV 16 integration and multiple HR-HPV infection containing HPV 16 with the severity of cervical lesions were assessed.3. Multiple PCR was performed to detect E2 and E6 genes of HPV type 58 in a series of 73 LBC samples from women with CC(N=7), CINâ…¡/â…¢(N=20), CINâ… (N=15), and chronic cervicitis (N=11). Additionally,20 samples from women without cervical neoplasia were analyzed as control. All of the specimens were infected with HPV type 58. E2/E6 ratio was used to evaluate the physical status of HPV58. The difference between the integration prevalence of HPV types 16 and 58 in cervical lesions were analyzed. Finally, the relationship between HPV 58 integration and the severity of cervical lesions were evaluated.Results1. The prevalence of HPV was 82.84% in CC,89.56% in CINâ…¡/â…¢, and 70.56% in CINâ… , while 44.70% in control. The five leading genotypes in CINâ…¡/â…¢were, in descending order of prevalence, HPV16 (61.12%),58(14.12%),33(13.93%),31(8.32%) and 52(6.27%); Whereas HPV16 (73.13%),18(7.46%),58(3.73%),and 31/33/39(all were 2.24%) in CC. Multiple HPV infections, comprising two to five types, were found in 17.59% of the patients. HPV 16 was the predominant genotype in all categories. The prevalence of both HPV 16 and single HPV infection increased with the severity of cervical lesions (P=0.000).2. The frequency of HPV-16 integration was 67.96% (70/103) in CC,21.37% (75/351) in CINâ…¡/â…¢I,8.82%(3/34) in CINâ… ,7.69% (5/65) in chronic cervicitis, and 5.00% (2/40) in control respectively. The frequency of HPV-16 viral integration increased in parallel with the severity of cervical lesions (P= 0.000). No association was observed between multiple HR-HPV infection containing HPV-16 and the severity of cervical lesions as well as HPV 16 integration, but in the case of single HPV 16 infection the situation was on the contrary (P= 0.000).3. The frequency of HPV-58 integration was 28.57% (2/7) in CC,20.00% (4/20) in CINâ…¡/â…¢,13.33% (2/15) in CINâ… ,9.09% (1/11) in chronic cervicitis, and 10.00% (2/20) in women with normal cervical cytology respectively. The frequency of HPV-58 viral integration tend to increased with the severity of cervical lesions, but the difference was not statistical significant (P=0.566). The frequency of HPV 58 integration in cervical cancer samples was different than that of HPV 16, the disparity was statistical significant (P= 0.047).Conclusion1. The efficacy of the prophylactic vaccine against types 16 and 18 for preventing cervical cancer would be close to 80% in Liaoning Province, China. HPV 16,18,58, 33 and 31 may be predominant high-risk factors for CC and its precursors in this region.2. HPV 16 integration was an early event in cervical carcinogenesis. The frequency of HPV-16 viral integration increased in parallel with the severity of cervical lesions, indicating the integration of HPV-16 DNA into host genomes could be a useful biomarker for progressive disease. HPV-16 infection was the predominant high risk factor for cervical carcinogenesis.3. A considerable portion of cervical cancer specimens were found episomal form of HPV type 16(32.04%) or 58(72.43%), indicating other pathogenesis bypass E2 gene disruption in the process of CC carcinogenesis induced by HR-HPV infection.4. The profile of HPV-58 integration in cervical lesions was different from that of HPV 16. The integration of HPV 58 DNA in cervical cancer was an infrequent event, suggesting that the pathogenesis may be different for specific HR-HPV type in CC carcinogenesis.5. No associations were found between multiple HR-HPV infection and the severity of cervical lesions or HPV-16 integration, indicating an antagonism interaction may exist among multiple HR-HPV infection in CC carcinogenesis. |
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