Genomic diversity of human papillomavirus-16, 18, 31, and 35 isolates in a Mexican population and relationship to European, African, and Native American variants

Cervical cancer, mainly caused by infection with human papillomaviruses (HPVs), is a major public health problem in Mexico. During a study of the prevalence of HPV types in northeastern Mexico, we identified, as expected from worldwide comparisons, HPV-16, 18, 31, and 35 as highly prevalent. It is well known that the genomes of HPV types differ geographically because of evolution linked to ethnic groups separated in prehistoric times. As HPV intra-type variation results in pathogenic differences, we analyzed genomic sequences of Mexican variants of these four HPV types. Among 112 HPV-16 samples, 14 contained European and 98 American Indian (AA) variants. This ratio is unexpected as people of European ethnicity predominate in this part of Mexico. Among 15 HPV-18 samples, 13 contained European and 2 African variants, the latter possibly due to migration of Africans to the Caribbean coast of Mexico. We constructed phylogenetic trees of HPV-31 and 35 variants, which have never been studied. Forty-six HPV-31 isolates from Mexico, Europe, Africa, and the United States (US) contained a total of 35 nucleotide exchanges in a 428-bp segment, with maximal distances between any two variants of 16 bp (3.7%), similar to those between HPV-16 variants. The HPV-31 variants formed two branches, one apparently the European, the other one an African branch. The European branch contained 13 of 29 Mexican isolates, the African branch 16 Mexican isolates. These may represent the HPV-31 variants of American Indians, as a 55% prevalence of African variants in Mexico seems incomprehensible. Twenty-seven HPV-35 samples from Mexico, Europe, Africa, and the US contained 11 mutations in a 893-bp segment with maximal distances between any two variants of only 5 mutations (0.6%), including a characteristic 16-bp insertion/deletion. These HPV-35 variants formed several phylogenetic clusters rather than two- or three-branched trees as HPV-16, 18, and 31. An HPV-35 variant typical for American Indians was not identifiable. Our research suggests type specific patterns of evolution and spread of HPV-16, 18, 31, and 35 both before and after the worldwide migrations of the last four centuries. The high prevalence of highly carcinogenic HPV-16 AA variants, and the extensive diversity of HPV-18, 31, and 35 variants with unknown pathogenic properties raise the possibility that HPV intra-type variation contributes to the high cervical cancer burden in Mexico.     

Detection of human papillomavirus genotypes with liquid bead microarray in cervical lesions of northern Chinese patients

Human papillomavirus (HPV) is the main cause of cervical cancer. Blending multiplex polymerase chain reaction (PCR) amplification and multiplex hybridization to liquid bead microarray (LBMA), we detected and identified 25 common HPV genotypes using type-specific primers for HPV E6 and E7 genes in cervical lesions of northern Chinese patients. Of the 511 cervical samples, 349 (68.3%) were found to be HPV positive by HPV-LBMA. The distribution was 22 HPV positive of 100 in the control group (22%), 41 of 80 with chronic cervicitis (51%), 80 of 99 with cervical intraepithelial neoplasia (CIN) I (81%), 46 of 56 with CIN II (82%), 67 of 74 with CIN III (90%), and 93 of 102 with invasive cervical carcinoma (91%). HPV-16 was the most frequent genotype in the CIN and cervical cancer groups. The most common genotypes were HPV-16 (28%), HPV-58 (14%), HPV-52 (14%), HPV-18 (8%), and HPV-33 (7%) in the CIN group, and HPV-16 (63%), HPV-52 (9%), HPV-18 (7%), HPV-58 (7%), and HPV-33 (5%) in the cervical cancer group. HPV-LBMA found multiple genotypes in 1 of 22 control (4%), 64 of 193 CIN (33%), and 22 of 93 cervical cancer (24%). The HPV-LBMA results were compatible with those of PCR and DNA sequencing. HPV-LBMA is a simple, high-throughput method that provides useful information on viral genotype and multiple HPV infections in cervical lesions. In northern China, the most common high-risk HPV genotypes seem to be HPV types 16, 58, 52, 18, and 33. Genetic information on HPV in cervical specimens could provide particular benefits in the management of cervical lesions.     

Distribution of human papillomavirus genotypes in women with high-grade cervical intraepithelial lesions and cervical carcinoma and analysis of human papillomavirus-16 genomic variants

AimTo analyze the distribution of high-risk human papillomavirus (HR-HPV) genotypes and the diversity of HPV-16 genomic variants in Croatian women with high-grade squamous intraepithelial lesions (HSIL) and cervical carcinoma.MethodsTissue biopsy specimens were obtained from 324 women with histopathologically confirmed HSIL or cervical carcinoma, 5 women with low-grade SIL, and 49 women with negative histopathology. HR-HPV DNA was detected with Ampliquality HPV-type nucleic-acid hybridization assay, which identifies 29 different HPV genotypes. HPV-16 genomic variants were analyzed by an in-house sequencing.ResultsThe most common HPV type in women with HSIL was HPV-16, detected in 127/219 (57.9%) specimens. HPV-16 was also the dominant type in squamous cell cervical carcinoma (46/69 or 66.7%) and in adenocarcinoma (18/36 or 50.0%). Out of 378 patients, 360 had HR-HPV (282 single infections and 79 multiple infections), 3 (0.8%) patients had low-risk HPV, and 15 (4%) tested negative. HPV-16 variants were determined in 130 HPV-16 positive specimens, including 74 HSIL and 46 carcinoma specimens. In HSIL specimens, 41 distinct variants were found, 98.6% belonging to the European branch and 1.4% belonging to the African branch. In cervical carcinoma specimens, 95% isolates grouped in 41 variants belonging to the European branch, one isolate (2.5%) belonged to the North American, and one (2.5%) to the Asian-American branch.ConclusionHPV-16, mainly belonging to the European branch, was the most frequent HPV genotype in women from Croatia with histologically confirmed HSIL and cervical cancer.

Cervical cancer is the second leading cause of death in women in low-income countries (1). Persistent infection with particular human papillomavirus (HPV) genotypes is a necessary but not a sufficient requirement for the development of cervical cancer (2). HPV DNA is detected worldwide in nearly all specimens of invasive cervical cancer, including squamous cell carcinomas, adenocarcinomas, and the majority (>95%) of immediate cervical cancer precursors (3). An epidemiological study by Bosch et al (4) has shown that the most common HPV genotypes in HSIL and squamous cell carcinomas were HPV-16, HPV-18, HPV-31, HPV-33, HPV-35, HPV-45, HPV-52, and HPV-58, with a combined worldwide relative contribution of 91% and the predominant role of HPV-16, HPV-18, and HPV-45 in cervical adenocarcinoma.HPV genomic variants are defined as the viruses that vary by 2% or less in specified regions of the genome, and some display different oncogenicity (5). HPV-16 heterogeneity has been extensively investigated (6-12), and HPV-16 genomic variants have been identified to belong to five main branches: European, Asian-American, two African branches, and an Asian branch (13). Two subsequent studies expanded these classifications and reported a new branch: North American 1 (14,15).Epidemiological studies have shown that non-European HPV-16 variants may promote viral persistence and disease progression (16-19). HPV-16 E6 variants, including the European HPV-16 T350G variant in the E6 gene, were detected up to 20 times more often in patients with high-grade cervical disease compared with controls. A novel HPV-16 variant, identified in Croatia, harboring a 63-bp in-frame duplication in the E1 gene, was presumed to be of reduced oncogenicity (11).According to the several national or regional studies in women with normal and abnormal cytology, HPV-16 is the most common high-risk genotype in Croatian women (20-27). However, none of these studies involved HPV genotyping in tissue specimens, and the majority were performed in general population with a small number of women with histologically confirmed HSIL or cervical cancer. The genomic diversity of high-risk HPV genotypes in Croatia has not been studied to date. On the other hand, recommended, non-mandatory, free-of-charge, nine-valent HPV vaccine is available in Croatia and is intended for vaccination of both women and men aged 14 to 25 years (28).The aims of this study were to analyze the distribution of high-risk HPV genotypes (HR-HPV) in women with histologically confirmed HSIL and cervical carcinoma and to analyze the genomic diversity of HPV 16 in HSIL in comparison with invasive cervical cancer.     

Distinctive distribution of HPV16 E6 D25E and E7 N29S intratypic Asian variants in Korean commercial sex workers

The distribution of HPV16 sequence variations differs geographically and specific HPV16 E6 and E7 variants might carry a high risk for development of invasive cervical cancer and cervical intraepithelial neoplasia in a given population. To investigate the genetic variation of HPV 16 E6 and E7 genes, genomic DNAs from 56 HPV16-infected commercial sex workers were extracted from their cervical swabs by using DNA isolation kit. The E6 and E7 coding region (34-880) with HPV16 E6/E7 specific PCR were amplified and analyzed by using the DNAstar software. At the nucleotide level, 26 variants of the HPV16 E6 and E7 genes were identified including 12 silent mutations. At the amino acid level, the isolates showed 14 variants including E6 Q14H, E6 D25E, E6 I27R, E6 H78Y, E6 L83V, and E7 N29S. The dominant HPV16 E6 and E7 variants were HPV16 E6 D25E (68%) and HPV16 E7 N29S (73%), respectively, which belong to Asian lineage. Although this study has some limitations such as a small sample size and not enough clinical data, these finding suggests that the distinctive distribution of HPV 16 As-variant E6 D25E and E7 N29S might be associated with geographical dependence rather than disease progression. Further study is needed to determine the clinical and biological effects of these variants.     

Human papillomavirus-16 E6 variants in cervical squamous intraepithelial lesions from HIV-negative and HIV-positive women.

We studied 48 human papillomavirus (HPV)-16-positive squamous intraepithelial lesions (SILs) from HIV-negative patients (16 low-grade SILs [LSILs]; 32 high-grade SILs [HSILs]) and 13 HPV-16-positive SILs from HIV-positive patients with AIDS (1 LSIL; 12 HSILs). After HPV typing, the entire HPV-16 E6 coding region was amplified and sequenced in all samples. We detected 12 HPV-16 E6 prototypes and 4 variants among the LSILs in HIV-negative patients, and 15 HPV-16 E6 prototypes and 17 HPV-16 variants in the HSIL group. The most prevalent variant of SIL types was European 350G, present in 3 and 13 cases, respectively. In 3 HSILs and no LSILs we found mixed infection by an HPV-16 E6 prototype and a variant. Two variants (1 each in LSIL and HSIL) were of non-European lineage. The only LSIL in HIV-positive patients had an HPV-16 E6 prototype; in the HSILs, we found 8 HPV-16 E6-prototypes, 4 with mixed infection with HPV-31 and 4 variants, all European 350G. The higher proportion of HPV-16 E6 variants in HSIL than in LSIL in HIV-negative patients suggests a greater risk of progression. However, further studies are needed.     

Sequence variants of human papillomavirus type 16 in clinical samples permit verification and extension of epidemiological studies and construction of a phylogenetic tree.

Genomic variability between different viral isolates provides a powerful epidemiological tool for verifying ultrasensitive diagnostic procedures, understanding infectious pathways in individuals and human populations, and studying viral evolution. The potential of this approach has not yet been exploited for the diagnosis of human papillomaviruses (HPVs) like HPV type 16 (HPV-16), which are involved in genital cancer. Toward this end, we amplified by polymerase chain reaction, cloned, and sequenced a 364-bp noncoding segment of the HPV-16 genome from cell lines, cervical biopsy specimens, and cervical smears. The HPV-16 genomes in the cell lines SiHa and CaSki showed an identical point mutation, and in the SiHa cell line it had an additional 38-bp deletion. Only 4 of 22 cervical lesions biopsied from patients at several hospitals in Singapore contained HPV-16 DNA with the prototype sequence, while the DNAs of the other 18 cervical lesions differed by 1 to 10 mutations. This excludes contaminations with cloned HPV-16 DNA as the source of this DNA. To test whether this diversity was a geographic idiosyncrasy, we analyzed 25 cervical biopsy specimens from Brazil. Eight of these contained the prototype sequence, while 17 were mutated. Altogether, 11 genomic variants were found in the Singaporean samples and 12 genomic variants were found in the Brazilian samples, and only 5 of these occurred identically in both cohorts. All variants could be connected to form a phylogenetic tree, with some branches being specific for each cohort. This suggests that the variants did not originate over a short period in the individual patient but, rather, evolved consecutively while spreading throughout humankind.(ABSTRACT TRUNCATED AT 250 WORDS)     

Distribution and viral load of type specific HPVs in different cervical lesions as detected by PCR-ELISA

AIMS: To investigate the distribution and viral load of the most prevalent high risk human papillomavirus (HPV) types 16, 18, 31, 33, and 45 and low risk HPV types 6 and 11 in a variety of cervical lesions. METHODS: One hundred and seventy six cytological specimens from women with different cervical lesions were investigated. For an accurate standardisation of the sample, cervical cells were counted and a volume of the cell suspension processed by polymerase chain reaction-enzyme linked immunosorbent assay (PCR-ELISA). Semiquantitative determinations were achieved in relation to an external reference titration curve. RESULTS: HPV DNA was detected in 60.2% of the samples. HPV-16 was the prevalent genotype (57.6%), followed by HPV-33, HPV-31, HPV-6, HPV-18, and HPV-45. HPV-11 was not detected. HPV-16 showed a pronounced increase in prevalence with the evolution of cervical disease. Semiquantitative evaluation of the results showed that only HPV-16 DNA could reach very high values (> 1000 genome copies/cell) and a very high HPV-16 load correlated with the severity of cervical disease. CONCLUSIONS: Only HPV-16 load appears to be associated with the severity of cervical disease.     

Human papillomavirus type 16 variants in cervical cancer from an admixtured population in Brazil

Several studies indicate that molecular variants of HPV-16 have different geographic distribution and risk associated with persistent infection and development of high-grade cervical lesions. In the present study, the frequency of HPV-16 variants was determined in 81 biopsies from women with cervical intraepithelial neoplasia grade III or invasive cervical cancer from the city of Belem, Northern Brazil. Host DNAs were also genotyped in order to analyze the ethnicity-related distribution of these variants. Nine different HPV-16 LCR variants belonging to four phylogenetic branches were identified. Among these, two new isolates were characterized. The most prevalent HPV-16 variant detected was the Asian-American B-2, followed by the European B-12 and the European prototype. Infections by multiple variants were observed in both invasive cervical cancer and cervical intraepithelial neoplasia grade III cases. The analysis of a specific polymorphism within the E6 viral gene was performed in a subset of 76 isolates. The E6-350G polymorphism was significantly more frequent in Asian-American variants. The HPV-16 variability detected followed the same pattern of the genetic ancestry observed in Northern Brazil, with European, Amerindian and African roots. Although African ancestry was higher among women infected by the prototype, no correlation between ethnical origin and HPV-16 variants was found. These results corroborate previous data showing a high frequency of Asian-American variants in cervical neoplasia among women with multiethnic origin.     

人乳头瘤病毒16型E6和E7基因特征分析

目的 对北京15例宫颈癌病变组织中的人乳头瘤病毒(HPV)16型E6和E7基因进行扩增及序列测定,分析E6和E7基因突变特征,并探讨宫颈癌病变中HPV16的感染情况.方法 自行设计HPVl6型E6和E7基因扩增引物,采用PCR法扩增15例宫颈癌组织中HPV16 E6和E7片段,将PCR产物克隆到TA载体,进行序列测定.通过Sequencer、Bioedit、Mega等生物学软件对E6和E7基因进行核苷酸和氨基酸序列分析.结果 15例宫颈癌中8例鳞癌检出E6和E7基因,检出率为8/15.2例腺癌、1例腺鳞癌和其他4例鳞癌中均未检出HPV16 E6E7 DNA.8例鳞癌中的4例检出的HPVl6为亚洲类似株,在E6基因178位(T→G,D25E)和E7基因647位(A→G,N29S)发生突变;另外4例为欧洲类似株,其中1例(BJ16)的HPV16在E6基因335位点发生突变(C→T,H78Y).结论 HPV16是致宫颈癌的重要因素;宫颈鳞状细胞癌HPV16感染的发生频率较腺癌和腺鳞癌高;E6基因178位点可能是区分亚洲株和欧洲株的重要位点;E6基因178位点和E7基因647位点是突变频率较高的位点,可能导致HPV16致癌能力发生改变.     

Human papillomavirus type-16 variants in Quechua aboriginals from Argentina

Cervical carcinoma is the leading cause of cancer death in Quechua indians from Jujuy (northwestern Argentina). To determine the prevalence of HPV-16 variants, 106 HPV-16 positive cervical samples were studied, including 33 low-grade squamous intraepithelial lesions (LSIL), 28 high-grade squamous intraepithelial lesions (HSIL), 9 invasive cervical cancer (ICC), and 36 samples from women with normal colposcopy and cytology. HPV genome variability was examined in the L1 and E6 genes by PCR-hybridization. In a subset of 20 samples, a LCR fragment was also analyzed by PCR-sequencing. Most variants belonged to the European branch with subtle differences that depended on the viral gene fragment studied. Only about 10% of the specimens had non-European variants, including eight Asian-American, two Asian, and one North-American-1. E6 gene analysis revealed that 43% of the samples were identical to HPV-16 prototype, while 57% corresponded to variants. Interestingly, the majority (87%) of normal smears had HPV-16 prototype, whereas variants were detected mainly in SIL and ICC. LCR sequencing yielded 80% of variants, including 69% of European, 19% Asian-American, and 12% Asian. We identified a new variant, the Argentine Quechua-51 (AQ-51), similar to B-14 plus two additional changes: G7842-->A and A7837-->C; phylogenetic inference allocated it in the Asian-American branch. The high proportion of European variants may reflect Spanish colonial influence on these native Inca descendants. The predominance of HPV-16 variants in pathologic samples when compared to normal controls could have implications for the natural history of cervical lesions.     

Correlation between human papillomavirus infection and histopathological diagnosis of women in Northeast Brazil

Cervical carcinoma is the fourth leading cause of death among women worldwide. Epidemiological studies claim that human papillomavirus (HPV) infection is a necessary condition for cervical cancer development. Knowledge of the geographic distribution of HPV is important in guiding the introduction of prophylactic vaccines. This study analyzed the prevalence of HPV infection in cervical samples obtained from women with abnormal cervical histopathological diagnosis in Northeast Brazil. The study included an analysis of 211 women whose diagnosis was confirmed for cervical intraepithelial neoplasia type 1 (CIN-1), cervical intraepithelial neoplasia type 2 (CIN-2), cervical intraepithelial neoplasia type 3 (CIN-3), and cancer. The identification of the HPV genotypes was based on the polymerase chain reaction–restriction fragment length polymorphism technique. A total of 42.7% of the samples showed a single HPV infection, while 57.3% showed multiple infections. The most common genotypes detected were HPV-16, HPV-18, and HPV-31. HPV-16, HPV-31, HPV-35, and HPV-18 were the most common types in CIN-1 with a single infection. HPV-16 and HPV-18 were the most often found in CIN-2 with a single infection. HPV-16, HPV-18, and HPV-31 were the most detected in CIN-3 with a single infection. HPV-16 and HPV-31 were the most frequent in cancer with a single infection. Multiple infection with HPV-16 shows a 2.7 times greater risk of CIN-3 (P = .04). Multiple infections for HPV with HPV-16 and excluding the HPV18/31 types, were associated with CIN-3 (P = .01). The results allowed the detection and genotyping of HPV types circulating in the population studied. These findings must be taken into account when devising vaccination strategies against HPV.     

Analysis of human papillomavirus type-16 variants in Italian women with cervical intraepithelial neoplasia and cervical cancer

Human papillomavirus type 16 (HPV-16) classes (E, AA, As, Af1, Af2) and their variants have different geographic distribution and different degrees of association with cervical lesions. This study was designed to examine HPV-16 variants among Italian women and their prevalence in case patients (affected by invasive cervical carcinoma or cervical intraepithelial neoplasia grade 2-3 and cervical intraepithelial neoplasia grade 1), versus control subjects with normal cervical epithelium (controls). A total of 90 HPV-16 positive cervical samples from women of Italian Caucasian descent have been tested, including 36 invasive cervical carcinomas, 21 with cervical intraepithelial neoplasias grade 2-3, 17 with cervical intraepithelial neoplasia grade 1 and 16 controls. HPV-16 was detected with an E6/E7 gene-specific polymerase chain reaction, and variant HPV-16 classes and subclasses were identified by direct nucleotide sequencing of the region coding for the E6 and the E7 oncoproteins, the MY09/11-amplified highly conserved L1 region, and the long control region (LCR). Among the 90 HPV-16 samples, nine viral variants have been identified belonging to the European (Ep-T350 and E-G350) and non-European (AA and Af-1) branches. The E-G350 is the prevalent variant in all analyzed different disease stages being present in 55.5% of ICC, 52.4% of cervical intraepithelial neoplasias 2-3, 47.1% of cervical intraepithelial neoplasia grade 1, and 50.0% of control samples. The non-European variants AA and Af1, rarely detected in control samples, represent 33.3% of all HPV-16 infections in invasive cervical carcinoma (with a peak of 19.4% and 13.9%, respectively), showing a statistically significant increase in frequency in more advanced lesions (chi(2) trend = 7.2; P < 0.05). The prevalence of HPV-16 Ep-T350, however, is higher in controls (43.7%) and in of cervical intraepithelial neoplasia grade 1 (41.2%) than in cervical intraepithelial neoplasia grade 2-3 (28.6%) and in invasive cervical carcinoma (11.1%) cases strongly suggesting lack of progression for pre-neoplastic lesions associated with such variant. The increased frequency of non-European variants in invasive lesions suggests that they are more oncogenic than European variants. This could have implications for future diagnostic and therapeutic strategies.     

Human papillomavirus: current status and issues of vaccination

An association between human papillomavirus (HPV) infection and the development of cervical cancer was initially suggested over 30 years ago, and today there is clear evidence that certain subtypes of HPV are the causative agents of such malignancies. Papillomaviruses make up a vast family that comprises hundreds of different viruses. These viruses infect epithelia in humans and animals and cause benign hyperproliferative lesions, commonly called warts or papillomas, which can occasionally progress to squamous cell cancer. HPV infections are considered the most common among sexually transmitted diseases. One of the most prevalent cancer types induced by HPV (mostly types 16 and 18) is cervical cancer. Vaccination is the most effective means of preventing this infectious disease. These prophylactic vaccines, based on virus-like particles (VLPs), are extremely effective in providing protection from infection in almost 100 % of cases. VLP vaccines of HPV are subunit vaccines consisting only of the major viral capsid protein of HPV. There are two types of vaccine available: bivalent vaccine (against HPV-16/18) and quadrivalent vaccine (against HPV-6/11/16/18). Second-generation prophylactic HPV vaccines, currently in clinical trials, may hold several merits over the current bivalent and quadrivalent vaccines, such as protection against additional oncogenic HPV types, less dependence on cold-chain storage and distribution, and non-invasive methods of delivery.     

Molecular variants of HPV type 16 E6 among Mexican women with LSIL and invasive cancer.

BACKGROUND: Cervical cancer is the second most common cancer in women worldwide. Infection with human papillomavirus (HPV) 16 is an important risk factor associated with cervical cancer, more than 50% of cervical cancer tissues have DNA of HPV 16. Intratypic variants have been reported, although they differ in prevalence, biological and biochemical properties, their implication in the aetiology of cervical cancer is still uncertain. OBJECTIVE: To identify HPV type 16 E6 variants among Mexican women with diagnosis of low-grade squamous intraepithelial lesion (LSIL) or invasive cancer (IC). STUDY DESIGN: Forty HPV16-positive samples were included, 15 were from women with LSIL, 25 from women with IC; 610 pb from the E6 gene were amplified by PCR and the variant status subsequently determined by hybridization with 27 biotinilated probes. Statistical analysis was performed with chi2, odds ratio (OR). RESULTS: In the LSIL group we only found ten (66%) EP and five (33%) EP350G variants. In the IC group, four variants were found; 11 (44%) AA, seven (28%) EP, six (24%) EP350G, one (4%) Af2. Comparison of the frequency of variants differed from EP in both groups of patients (P=0.01) with an odds ratio (OR) of 5.14 (CI 95% [1.07-26.56]). CONCLUSION: This study demonstrates an association between HPV type 16 variants different from prototype (EP) and invasive cervical cancer.     

E6 and E7 oncoproteins from human papillomavirus type 16 induce activation of human transforming growth factor beta1 promoter throughout Sp1 recognition sequence

Human Papillomavirus (HPV) infection is the main etiologic agent of cervical cancer and HPV E6 and E7 oncogenes trans-regulate many cellular genes. An association between TGF-beta1 gene expression and cervical cancer development has been suggested; however, the mechanisms by which HPV influences TGF-beta1 expression remain unclear. In the present study we analyzed the mechanism through which HPV-16 E6 and E7 oncoproteins regulate the TGF-beta1 promoter in cervical tumor cells. Our results showed that E6 and E7 increased TGF-beta1 promoter activity. Furthermore, we identified a specific DNA sequence motif in the TGF-beta1 core promoter that is responsible for trans-activation and that corresponds to the Sp1e-binding site associated with HPV-16 E6 and E7 oncoproteins. Mutational analysis showed that the Sp1e recognition site abolished the trans-activation caused by E6 and E7. These results suggest a physical interaction and functional cooperation between viral oncoproteins and cellular regulatory elements of the TGF-beta1 promoter, and may explain the contribution of HPV-16 to TGF-beta1 gene expression in cervical cancer.     

98例宫颈癌人乳头状瘤病毒16型E6基因突变及多态性分析

目的 研究湖北地区宫颈癌患者人乳头状瘤病毒16型(HPV16)E6基因点突变分布及频率,与国内外其他研究人员发现的E6突变进行对比,分析E6突变在宫颈癌发生中的意义.方法 从宫颈癌患者手术切除标本中提取组织DNA,用HPV16 E6特异性引物进行PCR扩增,对扩增的E6基因片段进行测序分析.结果 在35例宫颈癌组织DNA中有18例发生E6基因178位核苷酸的突变,变突频率为51.43%,相应核苷酸改变为Asp→Glu,442位核苷酸有4例发生核苷酸序列的改变,突变频率为11.43%,另有10例发生1～2个核苷酸序列的改变.结论 湖北地区98例宫颈癌患者人乳头状瘤病毒E6基因存在高频率的178和442位核苷酸突变,一些为新发现的核苷酸序列的突变,这些突变在宫颈癌发生中的作用有待于进一步研究.     

Genomic diversity of human papillomavirus genotype 53 in an ethnogeographically closed cohort of white European women

Human papillomavirus (HPV) genotype 53 is classified taxonomically in alpha HPV genus-species 6, together with HPV-30, HPV-56, and HPV-66 and is considered to be one of three "probable high-risk" HPV genotypes. Recent worldwide comparison of 44 isolates of HPV-53 showed the existence of nine long control region (LCR) genomic variants, which formed a phylogenetic tree with two deep dichotomic branches. In order to investigate further the genomic diversity of HPV-53, a total of 94 isolates of HPV-53 obtained from an ethnogeographically closed cohort of 70 white European women was analyzed. The identification and characterization of HPV-53 genomic variants was based on analysis of three different HPV genomic regions: LCR, E6 and E7. A higher genomic diversity of HPV-53 was identified in the ethnogeographically closed cohort of white European women than has been reported previously on isolates collected worldwide. Altogether, 19 HPV-53 genomic variants, composed of 13 LCR, 13 E6, and 5 E7 genomic variants, were identified. Eleven out of 13 LCR, all E6, and four out of five E7 genomic variants were described for the first time. The present study confirmed dichotomic phylogeny of HPV-53 described previously and, in addition, showed for the first time that after a dichotomic split, both groups of HPV-53 genomic variants formed star-like phylogenetic clusters. In women with persistent HPV-53 infection, HPV-53 genomic variants remained unchanged for up to 51 months. In rare cases, infection with multiple HPV-53 genomic variants is possible. Taking into account the results of this and previous studies, at least 26 different HPV-53 genomic variants exist today.