A novel real-time genotyping assay for detection of the E6-350G HPV 16 variant

It has been suggested that some E6 human papillomavirus (HPV) type 16 variants could be involved in viral persistence and progression of HPV infection. A novel one-step allelic discrimination real-time PCR was evaluated for E6-350G variant detection in 102 endocervical HPV 16 positive samples. This assay was also used to assess the distribution of this variant in Spanish women with cervical cancer related to HPV 16.The detection limit for the allelic discrimination assay was 50 copies per reaction, even where the E6-350G variant represents only 20% of the variants in the sample. Complete concordance was observed between DNA sequencing and the novel AD RT-PCR assay. Fourteen E6-350T reference strains and 18 E6-350G variants were detected out of 32 endocervical samples from women with cervical cancer. The average age of women who were infected by the E6-350G HPV 16 variant was 10 years lower in these samples than in women who were infected by the reference strain.This novel allelic discrimination assay is a fast, sensitive and specific method for detection of the E6-350G HPV 16 variant.     

Molecular variants of human papillomavirus type 16 and 18 and risk for cervical neoplasia in Portugal

Persistent high-risk human papillomavirus (HPV) infection is considered as the central cause of invasive cervical cancer. Specific HPV 16 and 18 sequence variations were associated with an increased risk for progression. The purpose of this study was to analyze intratypic variations of HPV 16 and 18 within the E6 gene, MY09/11 and LCR regions, and to evaluate the risk of these variants for cervical neoplasia among Portuguese women. Cervical samples from 187 HPV 16-positive and 41 HPV 18-positive women with normal epithelium, cervical intraepithelial neoplasia, or invasive cervical cancer were amplified by type-specific PCR, followed by sequence and phylogenetic analysis. Sixteen new HPV 16 and 18 patterns are described in this paper. European HPV 16 variants were the most frequent (74.3%), particularly Ep-T350 (44.4%), followed by African (16.1%), and Asian-American (9.6%). Non-European HPV 16 variants were more frequent in pre-invasive lesions than in normal tissue and low-grade lesions. However, when analyzed separately, only African variants were associated significantly with an increased risk for cervical cancer. For HPV 18, the AsAi variant showed a trend, which was not statistically significant to an enhanced oncogenicity. European variants seemed to be significantly associated with a lower risk for cervical cancer development. The distribution of HPV 16 and 18 variants was not related to age or race among women living in the same geographical region. Knowledge of variants will be important for risk determination as well as for designing primers or probes for HPV detection methods, and for appropriate cervical cancer prevention strategies.     

High prevalence of human papillomavirus type 58 in Mexican colposcopy patients.

BACKGROUND: Cervical cancer is the second most common cancer of the women worldwide. Infection with some genotypes of human papillomavirus is the most important risk factor associated to cervical cancer. OBJECTIVE: To determine the prevalence and genotypes of papillomavirus in biopsies of women with squamous intraepithelial lesion and cervical cancer. STUDY DESIGN: Two hundred sequential patients of colposcopy clinic were studied. HPV diagnosis was done by polymerase chain reaction using MY09/MY11 primers, for genotyping line blot hybridization was used. RESULTS: A total of 186 women were beta globin positive; 104 (55.9%) had histology diagnosis of low-grade squamous intraepitelial lesions (LSIL), 67 (36.0%) high-grade squamous intraepitelial lesions (HSIL) and 15 (8.1%) invasive cervical cancer (IC). The prevalence of HPV was 56.4% (104/185); HPV 58 was founded in 28.5% of all positive women, HPV 16 in 25.7%, HPV 18 in 13.3%, HPV 33 in 11.4% and 31 in 8.5%. In all grades of the lesions HPV 58 was the most frequently. CONCLUSIONS: The high prevalence of HPV 58 among Mexican women with HSIL and IC, has important implications in prophylaxis.     

Detection of human herpes virus type 6 DNA in precancerous lesions of the uterine cervix

Human herpes virus type 6 (HHV-6) DNA has been suggested to be a cofactor to human papillomavirus (HPV) in cervical cancer. In a cross-sectional study, we investigated the association between HHV-6 DNA detected in cervical brushings and high-grade squamous intraepithelial lesions (HSIL), while controlling for genital infection with 27 genotypes of HPV. Of the 320 women recruited from an oncologic gynecology clinic, 50 had invasive cervical cancer, 65 had HSIL, 80 had low-grade squamous intraepithelial lesions (LSIL), and 125 were normal. Four of the seven HHV-6-positive women had HSIL. HHV-6 was associated with HSIL after adjusting for age and socioeconomic status (odds ratio [OR] of 10.9, 95% confidence interval [CI]: 1.1-107.1). This association was no longer significant after controlling for HPV (OR = 6.4, 95% CI = 0.3-128.5). HHV-6 was detected in cervical samples from women with precancerous and cancerous lesions of the cervix, but not significantly more frequently than in normal women.     

Association between human papillomavirus 16 E6 variants and human leukocyte antigen class I polymorphism in cervical cancer of Swedish women

Persistent infection with human papillomavirus (HPV), particularly HPV16, represents the prime risk factor in cervical carcinogenesis. HPV variants (e.g., within the E6 gene) together with immunogenetic factors of the host may be responsible either for effective viral clearance, or alternatively, for viral persistence. Peripheral blood from 27 HPV16 positive Swedish women with cervical carcinoma, who had previously been tested for HPV16 E6 variants, was used for human leukocyte antigen (HLA) class I typing. Women with HLA-B*44, HLA-B*51, or HLA-B*57 who were infected with the HPV16 E6 variant L83V had an approximately four- to fivefold increased risk for cancer compared with controls (odds ratio [OR] = 3.5, 95% CI = 1.1-11.1, OR = 4.2, 95% CI = 1.19-14.69, or OR = 4.67, 95% CI = 1.2-18.6, respectively). Epitope predictive algorithm with SYFPEITHI revealed that the variant at amino acid 83 affects the binding affinity in association with HLA-B*44. Interestingly, the HLA-B*15 allele seems protective because it was absent in HPV16 positive cancer. It is concluded that specific HLA class I alleles, combined with certain HPV16 E6 variants, may be crucial for immune surveillance in cervical carcinogenesis. The evaluation of associations of HLA alleles with HPV variants may be helpful in defining prognostic markers and in designing vaccines capable of mediating immune protection against HPV infection.     

The role of human papillomavirus in cyto-histological practice: distribution and prevalenceof hig-risk strains (16, 18, 31, 33, and 35) in intraepithelial lesions and neoplasia of the uterine cervix

INTRODUCTION: Many studies have already shown the association of persistent infection of human high risk papillomavirus (HPV) with the development of pre-invasive and invasive cervical disease. MATERIALS AND METHODS: We evaluated the use of high risk HPV testing in a study of about 1908 women, aged 29-78, who attending, from 1996 to 1998, the Sant'Anna Hospital in Turin for routine, second level smears and histopathological diagnosis. We considered all cervical lesions: ASCUS, LSIL, HSIL, squamous and adeno invasive cancers. HPV testing was performed by polymerase chain reaction (PCR) using L1 consensus primers which can detect almost all infections (high and low risk types). The most important high risk HPV types (16, 18, 31, 33 and 35) were tested using specific primers. RESULTS: The prevalence of high risk HPV was: ASCUS 42.2%, LSIL 39%, HSIL 73.5%, squamous invasive cancers 98.3% and adeno 100%. In addition HPV 16 is the most represented type in all lesions: ASCUS 40%, LSIL 62%, HSIL 71.2% squamous invasive cancers 73.3% and adeno 50.6%. In addition we study the mean age of cervical cancer onset compared with the different high risk HPV types. We found that HPV 18 related cancer occurs in younger women (mean age 41 years; range 39-42). CONCLUSIONS: The addition of high risk HPV testing to cytology may improve early identification of women at risk for cervical cancer.     

Human papillomavirus 16 E6, L1, L2 and E2 gene variants in cervical lesion progression

The human papillomavirus (HPV) 16 E6 genome variant 350G has been found to be more prevalent in women with persistent infection and cervical disease progression than the HPV16 E6 prototype 350T. In this study, we examined whether women who progressed to a high-grade lesion, yet were infected with the prototype 350T, showed variants in other HPV genes such as L1, L2 and E2. Although we detected variants within these genes, they could not explain this phenomenon. Indeed they correlated similarly with variant 350G and prototype 350T. These data indicate that polymorphisms in HPV16 E6 rather than in the other analyzed genes play a role in determining the risk for cervical lesion progression and that additional factors are likely to be required as well.     

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.     

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.     

Association of human papillomavirus type 16 and its genetic variants with cervical lesion in Korea

Persistent human papillomavirus type 16 (HPV16) is the major risk factor for cervical cancer. HPV16 intratypic variants differ in their geographical distribution and oncogenic potential. This study aimed to analyze the distribution of HPV16 variants and their association with cervical lesion histopathology in Korean women. In total, 133 HPV16‐positive cervical samples from women admitted to Seoul National University Boramae Hospital were analyzed by sequencing E6, E7, and L1 genes and the long control region (LCR), and the variant distribution according to cervical lesion grade was determined. Isolates were grouped into a phylogenetic lineage, and A1‐3, A4, C, and D sublineages were detected in 54.1, 37.8, 0.7, and 7.4% of samples, respectively. The most commonly observed LCR variations were 7521G>A (91.5%), 7730A>C (59.6%), and 7842G>A (59.6%). Furthermore, A4 or D sublineage‐positive women had a higher risk for cervical cancer than women who were positive for A1–3. Among HPV phylogenetic clusters, A1–3 was the predominant sublineage, and within A1–3, the 350G polymorphism was highly frequent. These results differed from those of previous studies in Korea and other Asian countries. The findings suggest that cervical neoplasia incidence in HPV16‐infected patients could be affected by the distribution of HPV16 variants in the population.     

The prevalence of HPV-18 and variants of E6 gene isolated from cervical cancer patients in Taiwan.

BACKGROUND: Cervical cancer is the second most common cancer in women worldwide. It has been considered that human papillomavirus (HPV) is associated with cervical cancer. Currently, more than 80 different serotypes of HPV have been characterized and they are divided into low- and high-risk groups. The most common types that lead to cervical cancer are HPV-16 and -18. The viral oncogenes E6 and E7 are associated with the development of cervical cancer. In previous study, the variants of HPV-16 E6 gene have been reported. It suggests that variants may influence the morbidity of carcinogenesis, but the variant study on HPV-18 remains unknown. OBJECTIVES: To identify the variants of integrated HPV-18 E6 gene in the prevalent infection of HPV-18 of cervical cancer patients. STUDY DESIGN: 25 cervical cancer patients were clinically identified and the biopsies were obtained. The infectious HPV types were identified by PCR and Southern blotting analysis. The DNA fragments of the integrated HPV-18 E6 were amplified by PCR and cloned. The nucleotide sequences were obtained by sequencing. RESULTS: The prevalence of HPV infection in our 25 cases was HPV-18 (100%) and 7 out of these 25 cases (28%) were co-infected with HPV-16. The most dominant mutation among 25 tested patients was a silence mutation C183G of the E6 coding region. CONCLUSIONS: The prevalent HPV infectious serotype is HPV-18, which differs from the worldwide prevalent type. The identified HPV-18 E6 variants had a unique silence mutation located on C183G in E6 coding region.     

A non-radioactive PCR-SSCP analysis allows to distinguish between HPV 16 European and Asian-American variants in squamous cell carcinomas of the uterine cervix in Colombia

Human Papillomavirus type 16 (HPV 16) DNA is regularly found in around 50% of all cervical carcinomas. Variants of this type have been found associated with different risks for cervical cancer development. Presence of HPV 16 variants in Colombia has not been previously reported. The aims of this study were to assess the feasibility of non-radioactive PCR-SSCP (polymerase chain reaction single-strand conformation polymorphism) analysis for determination of variability of ORF of E6, variability in the enhancer sequence of the LCR, and for establishment of the distribution of HPV 16 variants in invasive squamous cell carcinoma of the uterine cervix in Colombian women. Biopsies from 59 patients at the Instituto Nacional de Cancerología (INC) in Bogotá (Colombia) were collected. HPV detection was performed using universal primers. HPV 16 variants were detected by non-radioactive single-stranded conformational polymorphism (SSCP) analysis and direct sequencing. HPV 16 was detected in 57.6% of the tumors. The European branch was identified in 88.2% of the samples with the E-G350 class being the most prevalent variant (41.1%). The Asian-American branch was identified in 8.8% of the samples. Within this group it was possible to distinguish between c and a classes. It was not possible to determine the branch in 2.9% of the cases. A nucleotide transition (G to A) at position 7521 was the most prevalent variation (80%) found in the enhancer sequence of the LCR region. Conclusion: A non-radioactive PCR-SSCP analysis allowed us to distinguish between European and Asian-American branches of HPV 16, and to distinguish among classes in squamous cell carcinomas of the uterine cervix in Colombia. This method is an excellent alternative that can be used as a screening tool for identification of HPV 16 variants.     

Codon 72 polymorphism of p53 and HPV type 16 E6 variants as risk factors for patients with squamous epithelial lesion of the uterine cervix

The Arg/Arg genotype versus Arg/Pro or Pro/Pro at codon 72 of the p53 gene in association with human papillomavirus (HPV) 16 E6 variants has been implicated as a risk marker in cervical neoplasia. However, research on this topic has produced controversial results. The association of p53 codon 72 polymorphism alone and in combination with specific HPV 16 E6 variants with risk of developing squamous intraepithelial cervical lesion has been investigated in low and high‐grade squamous intraepithelial lesions and in HPV‐negative controls from an Italian population. The data obtained showed statistically significant different distribution of p53 genotypes between healthy controls and precursor lesions, with the p53 arginine homozygous increased in high‐grade squamous intraepithelial lesions. The T350G HPV 16 variant was the most frequent variant observed in the analyzed group of Italian women, showing a slight decreasing with the severity of the lesion. At the same time, the number of the prototype T350 slightly increased with the severity of the cytological lesions. In conclusion, p53 arginine homozygous was found to be increased in high‐grade lesions, supporting the results of previous investigations indicating that HPV‐positive patients with p53 Arg/Arg have an increased risk of developing pre‐cancerous lesions. In addition, T350G HPV 16 variant was over‐represented in p53 Arg homozygous women with cervical lesions. When p53 genotype and HPV 16 variants are considered together, no difference emerges between cases and controls so is not possible to assess that the oncogenic effect of HPV 16 T350G variant may be influenced by the p53 genotype. J. Med. Virol. 85:83–90, 2012. © 2012 Wiley Periodicals, Inc.     

Associations of high-risk HPV types and viral load with cervical cancer in China.

BACKGROUND: Cervical cancer is the second most common cancer in women worldwide. Infection with some genotypes of human papillomavirus is the most important risk factor associated with cervical cancer. OBJECTIVE: The aim of this study was to determine the prevalence and genotypes of HPV in China, and to evaluate the correlation between viral load of high risk HPV and cervical cancer and its precursors. STUDY DESIGN: A cross-sectional study was carried out, wherein cervical samples were collected from 541 patients with cervical cancer, 262 with CIN, 139 with cervicitis and 68 age-matched healthy controls. Hybrid Capture 2 was employed to detect HPV DNA. Specimens from HPV DNA positive cervical cancer were tested for HPV types by using type specific PCR and general primer PCR with sequence-based typing (GP PCR-SBT). RESULTS: Overall high risk HPV prevalence was 68.8% in CIN1, 80.3% in CIN2, 90.2% in CIN3, 90.9% in cervical cancer in situ, 89.9% in invasive cervical cancer and 25% in healthy controls from China. The most common HPV DNA type found in patients with cervical cancer was HPV16 (79.6%), followed by HPV58 (5.92%), HPV33 (3.29%), HPV18 (1.97%), HPV6 (1.97%), HPV31 (1.31%), HPV39 (1.31%), HPV68 (1.31%) and other HPV types (3.3%). It was found that there was a significantly increased risk of increasing CIN stage with high viral load. Frequency of low viral load found in the controls was 13.2% and 22.9% of CIN1, obtaining an OR of 4.2 (1.5-12.0). Associations (OR) among low viral load and CIN2/3, CIS, and CC were 6.7 (2.9-15.6), 9.4 (2.7-32.3) and 8.3 (3.7-18.4), respectively. While high viral loads were found in 5.9% of controls, 27.1% of CIN1, 42.1% of CIN2/3 and 48.5% of CIS, demonstrating increasing odds ratios with severity of disease (OR for CIS=68.0, 95% CI=17.8-259.7). CONCLUSIONS: HPV16 was the most common genotype in central China. The developing cervical cancer precursors were associated with elevated high-risk HPV viral load.     

Human papillomavirus and cancer: the epidemiological evidence.

OBJECTIVE: Summary of the studies carried out by the IARC on HPV and cervical cancer is presented. RESULTS: the first one was the international prevalence survey of HPV types in invasive cervical cancer (ICC) conducted in up to 22 countries. Overall, 99.7% of 1000 cases with histologically confirmed ICC were also shown to be HPV DNA positive using the GP5+/GP6+ or E7 primers, indicating that HPV is a necessary cause of cervical cancer. The most prevalent HPV types were HPV 16 (53%), HPV 18 (15%), HPV 45 (9%), HPV 31 (6%) and HPV 33 (3%). HPV 16 was the most common type in all geographical regions, followed by HPV 18 that was particularly, common in South-East Asia. The second set of studies included case-control studies carried out in 13 countries. They included about 2000 cases and 2000 controls. Positivity, for any HPV DNA yielded a pooled odds ratio (OR) of 70. The association was equally strong for both squamous cell (OR=74) and adenocarcinoma (OR=50) and for HPV 16 and 18 as well as for the less common HPV types. Our results indicate that in addition to HPV 16 and 18, HPV 31, 33, 35, 45, 51, 52, 58 and 59 now can be considered as carcinogenic. The third group of studies is aimed to determine the HPV DNA prevalence in random, age-stratified (by 5 years, 15-19 to 65+) subsamples (1100 women) of the general population. Two age-peaks (<25 and >59 years), have been found in some countries (Costa-Rica, Mexico, Colombia) but not in all (Argentina). Whether the second peak is due to viral reactivation, variations in screening or represents a birth-cohort effect remains to be determined. The distribution of the most prevalent HPV types in the general population (HPV 16, 18, 45, 31, 58, 33, 35) resembles that for cervical cancer cases. CONCLUSIONS: our studies provide the most solid epidemiological evidence, to conclude that HPV is not only the central cause of cervical cancer worldwide but also a necessary cause.     

Genetic diversity of human papillomavirus type 16 E6, E7, and L1 genes in Italian women with different grades of cervical lesions

High‐risk human papillomaviruses (HPVs) are risk factors for the development of cervical cancer. HPV 16 is the most common type, being present in about 60% of cervical cancers worldwide. Previous studies have reported upon the association between HPV 16 E6 variants and increased risk of cervical intraepithelial neoplasia and invasive cervical cancer. In this study, the presence of HPV 16 polymorphisms in the E6, E7, and L1 genes was investigated in relation to the presence of high‐grade lesions. Sequencing of the E6 gene revealed the presence of nucleotide mutations resulting in 15 amino acid changes. Of these, the G134D and C136R fall within the CXXC zinger finger domain important for p53 binding. In the E7 gene, four nucleotide variations were identified with two leading to the amino acid substitutions L15V and S31R. The L1 gene showed 13 nucleotide changes leading to 11 amino acid substitutions. Among these, the R364C and N367D are located at the base of the HI‐loop of the L1 protein, considered to be the immunodominant epitope of HPV 16. No significant relationship between HPV 16 variants and high‐grade lesions was found. Phylogenetic analysis showed that all the HPV 16 variants identified belonged to the European lineage, except one which was of the Asian‐American lineage. The European‐350G variant was detected most frequently (22 of 34, 64.7%). The study provides some new data on the genetic diversity of HPV 16 which may help to understand the oncogenic potential of the virus and to improve management of patients. J. Med. Virol. 81:1627–1634, 2009. © 2009 Wiley‐Liss, Inc.     

Implications of continued upregulation of p16(INK4a) through the evolution from high-grade squamous intraepithelial lesion to invasive squamous carcinoma of the cervix

On integration into the host cervical keratinocyte genome, human papillomavirus (HPV) E7 protein binds pRB,releasing E2F from normally incompetent pRB-E2F complexes and allowing propagation of G1-S transition by the E2F. p16(INK4a), a tumour suppressor protein, increases in reflex response to counter this. 29 histologically re-confirmed low-grade squamous intraepithelial lesions (LSIL), 27 high-grade squamous intraepithelial lesions (HSIL) and 30 invasive cervical squamous carcinoma (SCC) were immunohistochemically stained for p16(INK4a) expression using the CINtec Histology Kit (REF 9511, mtm laboratories AG, Heidelberg, Germany) to re-affirm the notion that integration of HPV occurs predominantly in SCC and possibly HSIL and less in LSIL and normal squamous epithelium (NSqE). Implicit was also the attempt to understand the role of E2F, as indicated by p16(INK4a), in evolution of SCC from HSIL. No ethnic predilection was noted for LSIL, HSIL or SCC. Patients with SCC were significantly older by about 14-years compared with HSIL (p < 0.05) while there was no significant age difference between HSIL and LSIL. p16(INK4a) expression was significantly increased (p < 0.05) in both HSIL (88.9%) and SCC (83.3%) compared with LSIL (3.4%) and NSqE (0%); the NSqE being normal squamous epithelium noted in 17 of the LSIL, 19 HSIL and 5 SCC. From these findings there is suggestion that fundamental upstream events viz HPV integration, E7 upregulation followed by E2F activation occurs at point of transformation to HSIL and continues unrelentingly for another one to two decades before hitherto unclear factors convert a non-invasive lesion into an overtly invasive malignant counterpart. Interestingly, the occurrence of HSIL and LSIL in almost the same age group could mean that alteration from episomal to integrated form of HPV may not incur a prolonged incubation period, unlike from HSIL to SCC.     

HPV16 E6 variants and HLA class II polymorphism among Chinese women with cervical cancer

Infection with human papillomavirus type 16 (HPV16) confers a high risk for the development of cervical cancer. Variants of this virus may interact differentially with host genetic factors, possibly affecting the disease pathogenesis. This study was designed to investigate the association between HPV16 E6 variants and human leukocyte antigen (HLA) polymorphism within a Chinese population. Peripheral blood from HPV16 positive Chinese women with cervical carcinoma, who had previously been tested for HPV16 E6 variants, was used for HLA class II typing. It was found that there was a significant positive association between DQB1*060101 allele and HPV16 As variant-positive cervical cancers (OR, 4.47; Pc=0.0018). A negative relationship was found between DRB1*150101-DQB1*0602 haplotype and decreased risk for HPV16 As variant-positive cervical cancers (OR=0.31; P=0.037). Similar tendency was observed for the haplotype DRB1*070101-DQB1*0201 with HPV16 As variant-positive cervical cancers (OR=0.16, P=0.024). Additionally, as for the HPV16 E6 prototype-positive cervical cancers, a significant positive association was found in DQB1*060101 allele (OR=5.95; P=0.002; Pc=0.036), and similar trends were observed for DQB1*030201 (OR=10.87, P<0.0001; Pc=0.0018), and DPB1*1301(OR=7.40, P=0.002; Pc=0.04). It was found that there was no significant association between DRB1-DQB1 haplotype and HPV16 prototype-positive cervical cancers. These data indicate that host genetic factors, such as HLA polymorphism, may determine the potential oncogenicity of the HPV16 E6 variant. The results suggest that a specific match between E6 variant proteins and HLA class II alleles may contribute to HPV16-related cervical carcinogenesis in a certain Chinese population.     

Detection of HPV16 and 18 by in situ hybridization in precancerous and cancerous lesions of cervix

Fifty cervical biopsies from women with preinvasive and invasive malignancies of uterine cervix and ten normal cervical biopsies were examined for the presence of human papilloma virus (HPV) 16 and 18 DNA sequences by in situ hybridization (ISH) method with biotinylated DNA probes. The overall positivity of HPV DNA was 48% (24/50). The positivity of HPV 16 DNA for low grade squamous intraepithelial lesion (LSIL), high grade squamous intraepithelial lesions (HSIL) and squamous cell carcinoma (SCC) were 33.33%, 45.45%, 42.30% respectively. The positivity for HPV 18 DNA for LSIL, HSIL and SCC were 0%, 18.18%, 30.76% respectively. Two cases of cervical adenocarcinomas showed positivity for HPV 18 DNA only.     

Cervical human papillomavirus (HPV) infection and HPV type 16 antibodies in South African women

There is a high incidence of cervical cancer in South African women. No large studies to assess human papillomavirus virus (HPV) infection or HPV type 16 (HPV-16) exposure have occurred in the region, a requirement for policy making with regards to HPV screening and the introduction of vaccines. Control women (n = 1,003) enrolled in a case control study of hormonal contraceptives and cervical cancer were tested for 27 cervical HPV types by reverse line blot analysis. The seroprevalence of HPV-16 immunoglobulin G (IgG) and IgA antibodies was assessed by a virus-like particle-based enzyme-linked immunoassay of 908 and 904 control women, respectively, and of 474 women with cervical cancer. The cervical HPV prevalence was 26.1%. The HPV-16 IgG seroprevalence was 44.4% and the HPV-16 IgA seroprevalence was 28.7% in control women, and these levels were significantly higher (61.8% and 52.7%, respectively) for women with cervical cancer (odds ratio [OR], 2.1 and 2.8, respectively). The cervical HPV prevalence showed an association with cervical disease, and the HPV-16 IgG prevalence decreased while the HPV-16 IgA prevalence increased with increasing age (P < 0.05). The prevalence of oncogenic HPV types (including HPV-16) decreased with age, whereas nononcogenic HPV types showed limited association with age. Multivariate analysis revealed cervical HPV infection to be associated with herpes simplex virus type 2 infection (OR, 1.7) and increasing years of education (OR, 1.9). HPV-16 IgG antibodies were inversely associated with current smoking status (OR, 0.6), and the presence of HPV-16 IgA antibodies was inversely associated with the use of alcohol (OR, 2.1) and inversely associated with the use of oral contraceptives (OR, 0.6). High levels of exposure to HPV, and particularly HPV-16, were evident in this population. The apparent increase of serum HPV-16 IgA with increasing age requires further investigation.