Predominance of genomically defined A lineage of HPV16 over D lineage in Indian patients from eastern India with squamous cell carcinoma of the cervix in association with distinct oncogenic phenotypes

Molecular epidemiology of human papillomavirus variants in cervical cancer in India

Background & objectives Cervical cancer (CC) has been documented as the fourth most common cancer worldwide. Persistent infections with high-risk human papillomavirus (hr-HPV) have been suggested in the development of CC. Although prophylactic vaccines are available for the prevention of prevalent hr-HPV types, intra-type variations exist within a particular HPV type that has varying oncogenic potential as well as the mechanism of pathogenicity and varying neutralization by antibodies. Therefore, we carried out a systematic review to determine the distribution of HPV intra-typic variations in different geographical locations of India and their reported implications. Methods Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were followed to retrieve relevant articles from the standard databases using appropriate keywords. Consequently, 17 articles were included in the current review after screening based on inclusion and exclusion criteria. Results The majority of articles included in this review reported variations within the HPV16 E6 gene, followed by the L1 and E7 genes. Analysis of available data indicated the differential regional distribution of some variations. These variations have also been reported to impact the biological functions of various viral proteins. Interpretation & conclusions The distribution of lineages varied with the different genomic regions sequenced. Additionally, there were certain unique and common variations in the HPV genome with respect to geographical regions. Hence, we suggest the identification of region-specific variations for the development of diagnostic and prognostic interventions.

Genetic variation of E6 and E7 genes of human papillomavirus type 16 from central China

BACKGROUND

Persistent high-risk human papillomavirus (HR-HPV) infection is an important factor in the development of cervical cancer, and human papillomavirus type 16 (HPV-16) is the most common HR-HPV type worldwide. The oncogenic potential of HPV-16 is closely related to viral sequence variation.

METHODS

In order to clarify the variant characteristics of HPV-16 E6 and E7 genes in central China, E6 and E7 sequences of 205 HPV-16 positive samples were amplified by polymerase chain reaction. PCR products of E6 and E7 genes were further sequenced and subjected to variation analysis, phylogenetic analysis, selective pressure analysis and B-cell epitope prediction.

RESULTS

Twenty-six single nucleotide variants were observed in E6 sequence, including 21 non-synonymous and 5 synonymous variants. Twelve single nucleotide variants were identified in E7 sequence, including 6 non-synonymous and 6 synonymous variants. Four new variants were found. Furthermore, nucleotide variation A647G (N29S) in E7 was significantly related to the higher risk of HSIL and cervical cancer. Phylogenetic analysis showed that the E6 and E7 sequences were all distributed in A lineage. No positively selected site was found in HPV-16 E6 and E7 sequences. Non-conservative substitutions in E6, H31Y, D32N, D32E, I34M, L35V, E36Q, L45P, N65S and K75T, affected multiple B-cell epitopes. However, the variation of E7 gene had little impact on the corresponding B-cell epitopes (score < 0.85).

CONCLUSION

HPV-16 E6 and E7 sequences variation data may contribute to HR-HPV prevention and vaccine development in Jingzhou, central China.

Distribution of Human Papillomavirus Genotypes among the Women of South Andaman Island, India

BACKGROUND

Human Papillomavirus (HPV) causes various types of cancer in both men and women. Woman with HPV infection has a risk of developing invasive cervical cancer. Globally, HPV 16 and 18 were predominant. This study aims to find the distribution of various HPV types in South Andaman.

METHODS

A cross-sectional study was conducted among women in South Andaman, where cervical scrapes were collected after collecting written informed consent. Detection of HPV genotypes was carried out by using a PCR assay. Further, sequencing analysis was performed using MEGA11 to identify various genotypes in this territory.

RESULT

Of these 1000 samples, 32 were positive for HR-HPV 16, and four were positive for HR-HPV 18. Fifteen HPV genotypes were detected using molecular evolutionary analysis. Six cases were identified with multiple genotypes. The most prevalent genotype is HPV 16 which belongs to Lineage-A and sub-lineage A2. HPV 18 identified in South Andaman belonged to the lineage A1 to A5.

DISCUSSION

Various HPV types were identified among women in South Andaman. Global burden of cervical cancer associated with various HPV sub-lineages. HPV-16 A1 sub-lineage was globally widespread, whereas sub-lineages A1, A2 and D1 prevailed in South Andaman.

CONCLUSIONS

HR-HPV identified in this study enlightens the importance of HPV vaccination among women in remote places. These findings will help to strengthen public health awareness programs and prevention strategies for women in remote areas.

Identification of HPV16 positive cervical cancer subsets characterized by divergent immune and oncogenic phenotypes with potential implications for immunotherapy

BACKGROUND

Cervical cancers (CaCx), like many other cancer types, portray high molecular heterogeneity that affects response to therapy, including immunotherapy. In India and other developing countries, CaCx mortality rates are very high because women report to the clinics with advanced cancers in absence of organized screening programs. This calls for implementation of newer therapeutic regimens for CaCx, like immunotherapy, which is again not used commonly in such countries.

OBJECTIVE

Therefore, we focused on dissecting tumour immune heterogeneity, if any, identify immune gene-based biomarkers of heterogeneity and subsets of such cancers with the potential for immunotherapy. We also attempted to characterize the cancer-associated phenotypes of such subsets, including viral load, to decipher the relationship of tumour immunogenicity with oncogenicity.

METHODS

Employing RNA-seq analysis of 44 HPV16 positive CaCx patients, immune subtypes were identified by unsupervised hierarchical clustering of global immune-gene expression profiles. Proportions of tumor infiltrating immune cells in the tumor milieu were estimated, employing Cell-type Identification by Estimating Relative Subsets of RNA Transcripts (CIBERSORT), using gene expression data from RNA-seq. The oncogenic phenotypes of the immune subtypes of CaCx were deciphered through differential gene expression (DEGs) and pathway enrichment analysis. Viral load was estimated through TaqMan-based qRT-PCR analysis.

RESULTS

Analysis revealed the presence of two immune subtypes of CaCx, A (26/44; 59.09%) and B (18/44; 40.90%). Compared to Subtype-A, Subtype-B portrayed overexpression of immune genes and high infiltration of immune cells, specifically CD8+ T cells (p < 0.0001). Besides, a significant correlation between PD-1 and PD-L1 co-expression among Subtype-B, as opposed to Subtype-A, confirmed the interactive roles of these immune checkpoint molecules in Subtype B. Stepwise discriminant analysis pin-pointed ten immune-genes that could classify 100% of the patients significantly (p < 0.0001) into the two immune subtypes and serve as potential biomarkers of CaCx immunity. Differential gene expression analysis between the subtypes unveiled that Subtype-B was more biologically aggressive than Subtype-A, reflecting loss of structural integrity and promotion of cancer progression. The viral load was significantly lower in Subtype-B (average viral load = 10.74/100 ng of genomic DNA) compared to Subtype-A (average viral load = 14.29/100 ng of genomic DNA). Thus viral load and the ten-gene panel underscore their association with immunogenicity and oncogenicity.

CONCLUSION

Our study provides strong evidence that only a subset, about 41% of HPV16 positive CaCx patients in India, portray immune enrichment of the tumor milieu coupled with aggressive phenotypes. Such subtypes are therefore likely to benefit through checkpoint molecule-based or tumor infiltrating lymphocyte-based immunotherapy, which could be a leap forward in tackling aggressive forms of such CaCx in India and other developing countries.

Genetic diversity of E6, E7 and the long control region in human papillomavirus type 16 variants in Beijing, China

Background

High-risk human papillomavirus type 16 (HPV16) is a risk factor for cervical cancer. The progression from initial infection to cervical cancer has been linked to properties of the viral sequences. However, the distribution of HPV16 variants among Chinese women has not been extensively addressed and the role of HPV16 variants in the risk of cervical carcinogenesis remains poorly understood.

Methods

HPV16 positive cervical exfoliated cell samples were collected from 249 women living in Beijing, China. PCR products from two fragments of E6-E7 and LCR of HPV16 in these samples were sequenced and analyzed.

Results

Lineage A was found in the subjects, including A1, A2, A3 and A4 sublineages. Based on the HPV16 reference sequences, 26 nucleotide mutations of A4 sublineage and 39 nucleotide mutations of A1-3 sublineages were found in the E6, E7 and LCR of HPV16 isolates. Point mutations T843C, A7287C and A7872G of A4 sublineage were significantly associated with high-grade cervical lesions. The high-frequency sites in HPV16 LCR located at regions that can bind to multiple transcription factors.

Conclusions

This study contributes to the identification of unique variants in the E6, E7 and LCR of HPV16 isolates infected in Chinese women. Mutations of T843C, A7287C and A7872G in A4 sublineages were significantly associated with high-grade cervical lesions, suggesting that mutations in the E7 and LCR region have potential effects on viral replication and progression of cervical cancer.

•

Lineage A is the predominant HPV16 variant in Chinese women.

•

Based on the HPV16 prototype, 25 nucleotide mutations in E6 and E7 were found and 41 nucleotide mutations in LCR were found.

•

The mutations of C843T, A7287C and A7872G were significantly correlated with the cervical lesions.