Human papillomavirus type 16 e6 gene variations in young Chinese women with cervical squamous cell carcinoma

Distribution of HPV 16 E6 gene variants in screening women and its associations with cervical lesions progression

The aim of this study is to investigate distribution of human papillomavirus (HPV) 16 variants in screening healthy women and the potential association between HPV 16 variants and progression of cervical lesions. For this study a total of 2000 healthy women in Tianjin urban area and 212 patients who were HPV 16 positive and underwent colposcopy were analyzed for HPV 16 variants by pyrosequencing. The results show that the HPV 16 was the most prevalent genotype in Tianjin healthy women and five HPV 16 variant types were detected. The HPV 16 variants were determined by sequencing parital E6 region and the detected variants were European prototype E-T350 (E-p), E-G350, E-C109 G, Asian (As) and Asian-American (AA), among which the E-p variant was the most prevalent (82.76%) followed by As variant. Interestingly, in patients with suspected cervical lesions the most prevalent variant was As variant (54.9%) by increasing significance with severity of cervical diseases (OR 4.337; 95% CI 1.248-15.067; P = 0.021), and followed by HPV 16 E-p variant while E-G350 variant only appeared in HSIL and cervical cancer. Our results show that HPV 16 E-p variant was more prevalent than As in Tianjin healthy screening women while As variant was the most frequently type in HSIL and cervical cancer. It is suggested that the mutation of HPV 16 Asian variants, comparing with HPV 16 E-p variants, might contribute to the transformation from HPV 16 persistent infection to cervical cancer.

Association of HLA-DRB1, HLA-DQB1 Polymorphisms with HPV 16 E6 Variants among Young Cervical Cancer Patients in China

Potential correlation of human papillomavirus (HPV) 16 E6 variants and human leukocyte antigen (HLA) class II polymorphisms has been suggested in patients with cervical cancer, so far little information is available about the possible interaction between E6 variants and HLA class II variability during the obviously accelerated progression to cervical cancer in young women. In this study, we aimed to explore the association between the HPV16 E6 variants and HLA-DRB1, DQB1 alleles in a Chinese young cervical cancer population. The HLA-DRB1, HLA-DQB1 polymophisms were genotyped by low-resolution polymerase chain reaction (PCR) with sequence-specific primer. HPV16 E6 DNA was tested by Sanger fluorescent dye dideoxy-termination technique. The difference of DRB1, DQB1 polymorphisms between young cervical cancer patients (≤35ys, n=61) and older ones (>35ys, n=85) and the association with E6 variants were analyzed. Results showed that the distribution pattern of HLA-DRB1, DQB1 alleles was different between young cervical cancer patients and older ones. The allele frequency of DQB1*0501 in young patients was significantly lower than older ones (6.6% vs. 23.5%, p<0.05). The HPV16 E6 A4 lineage was the exclusive type observed in young patients, and its prevalence was significantly higher than that of older cases (82.86% vs.41.94%, p<0.05). DRB1*03 was not found in young patients positive for the HPV16 E6 A4 lineage, whereas it was observed in 19.2 % older patients with A4 positive(Pc<0.05). In conclusion, specific association between certain HPV16 E6 variant and genetic polymorphisms of HLA may play a role during the progression of early onset cervical cancer in young patients. Certain HLA-DRB1 and HLA-DQB1 alleles may be related to the A4 lineage among young cervical cancer patients, which was the unique HPV16 E6 variant found in Chinese young patients. Our finding may provide an insight into the pathogenic factors that associated with cervical cancer in young women.

Whole genome sequencing and evolutionary analysis of human papillomavirus type 16 in central China

Human papillomavirus type 16 plays a critical role in the neoplastic transformation of cervical cancers. Molecular variants of HPV16 existing in different ethnic groups have shown substantial phenotypic differences in pathogenicity, immunogenicity and tumorigenicity. In this study, we sequenced the entire HPV16 genome of 76 isolates originated from Anyang, central China. Phylogenetic analysis of these sequences identified two major variants of HPV16 in the Anyang area, namely the European prototype (E(p)) and the European Asian type (E(As)). These two variants show a high degree of divergence between groups, and the E(p) comprised higher genetic diversity than the E(As). Analysis with two measurements of genetic diversity indicated that viral population size was relatively stable in this area in the past. Codon based likelihood models revealed strong statistical support for adaptive evolution acting on the E6 gene. Bayesian analysis identified several important amino acid positions that may be driving adaptive selection in the HPV 16 population, including R10G, D25E, L83V, and E113D in the E6 gene. We hypothesize that the positive selection at these codons might be a contributing factor responsible for the phenotypic differences in carcinogenesis and immunogenicity among cervical cancers in China based on the potential roles of these molecular variants reported in other studies.

Human papillomavirus type 16 variant analysis of E6, E7, and L1 [corrected] genes and long control region in [corrected] cervical carcinomas in patients in northeast China

Human papillomavirus type 16 (HPV 16) plays a cardinal role in the pathogenesis of cervical cancer. HPV 16 has intratypic variants which show different geographical distributions and different oncogenic potentials. To analyze the presence of sequence variations of HPV 16 variants in northeast China, 71 cervical carcinomas were identified by HPV typing. HPV 16-positive specimens were analyzed by PCR-directed sequencing in the E6, E7, and L1 genes and the LCR (long control region). The variation data were compared with those of neighboring districts. In this hospital-based study, HPV 16 was the most common type (73.24%). In HPV 16-positive specimens, 67.31% belonged to the European (E) lineage, while 32.69% were Asian (As) variants. The Asian-American (AA), African-1 (Af-1), African-2 (Af-2), and northern American (NA) lineages were not detected. The most frequently observed variation sites were T178G (32.69%) in E6; A647G (34.62%), G666A (38.46%), and T846C (32.69%) in E7; C6826T (36.17%) and G7060A (61.70%) in L1; and G7521A (98.08%) in the LCR. The most prevalent amino acid variations were D25E in E6 and N29S in E7. In addition, 28 novel variations of HPV 16 were reported. Some covariations between different genes were obtained. In this study, HPV 16 variants belonged to the European lineage and the Asian lineage. Compared with neighboring districts, the distribution of HPV 16 variants in northeast China had a typical pattern. As the first report on HPV 16 variants in northeast China, it should be helpful for designing a HPV vaccine and HPV vaccination program in China.