HPV genotyping and site of viral integration in cervical cancers in Indian women

HPV DNA Integration at Actionable Cancer-Related Genes Loci in HPV-Associated Carcinomas

In HPV-associated carcinomas, some examples of cancer-related genes altered by viral insertion and corresponding to potential therapeutic targets have been described, but no quantitative assessment of these events, including poorly recurrent targets, has been reported to date. To document these occurrences, we built and analyzed a database comprised of 1455 cases, including HPV genotypes and tumor localizations. Host DNA sequences targeted by viral integration were classified as "non-recurrent" (one single reported case; 838 loci), "weakly recurrent" (two reported cases; 82 loci), and highly recurrent (≥3 cases; 43 loci). Whereas the overall rate of cancer-related target genes was 3.3% in the Gencode database, this rate increased to 6.5% in "non-recurrent", 11.4% in "weakly recurrent", and 40.1% in "highly recurrent" genes targeted by integration (p = 4.9 × 10-4). This rate was also significantly higher in tumors associated with high-risk HPV16/18/45 than other genotypes. Among the genes targeted by HPV insertion, 30.2% corresponded to direct or indirect druggable targets, a rate rising to 50% in "highly recurrent" targets. Using data from the literature and the DepMap 23Q4 release database, we found that genes targeted by viral insertion could be new candidates potentially involved in HPV-associated oncogenesis. A more systematic characterization of HPV/host fusion DNA sequences in HPV-associated cancers should provide a better knowledge of HPV-driven carcinogenesis and favor the development of personalize patient treatments.

Preliminary study of HPV integration status on the occurrence and development of vaginal intraepithelial neoplasia

AIM

The aim of this study was to investigate how the integration status of HPV in the vaginal epithelium affects the development of vaginal intraepithelial neoplasia (VaIN).

METHODS

Twenty-four vaginal tissues were collected before applying high-throughput viral integration detection (HIVID), medical records of them were documented, including age, thin-prep cytologic test (TCT) and HPV test results, colposcopic biopsy pathology, and other clinical data, such as history of total hysterectomy for cervical lesions, whether they were infected with HPV16/18 with a follow-up span of 2 years. We summarized the distribution of HPV integration on the host chromosome and HPV type, as well as the hotspot integration gene and its role in the development of VaIN.

RESULTS

In this study, 24 cases suffered from VaIN were involved. HPV integration was detected in 11 cases; furthermore, we discovered HPV 16 and 73, chromosome 1 and 2 possessed most HPV integration sites while EMBP1, CLO5A1, EHF, ELF5 as dominate hot spots. Taken clinical outcome into account, we found a significant difference between HPV integration occurrence and VaIN (p = 0.011).

CONCLUSION

(1) This study found a statistical difference between HPV integration and the occurrence of VaIN; (2) HPV integration may provide a new clinical predictor for VaIN and facilitate risk assessment and stratified management of high-risk patients.

Long-read sequencing of oropharyngeal squamous cell carcinoma tumors reveal diverse patterns of high-risk Human Papillomavirus integration

Introduction

In North America and in most European countries, Human Papillomavirus (HPV) is responsible for over 70% of oropharyngeal squamous cell carcinomas. The burden of OPSCC, in high-income countries, has been steadily increasing over the past 20 years. As a result, in the USA and in the UK, the burden of HPV-related oropharyngeal squamous cell carcinoma in men has now surpassed that of cervical cancer in women. However, the oncogenic impact of high-risk HPV integration in oropharyngeal squamous cell carcinomas hasn't been extensively studied. The present study aimed to explore the patterns of HPV integration in oropharyngeal squamous cell carcinomas and to assess the feasibility and reliability of long-read sequencing technology in detecting viral integration events in oropharyngeal head and neck cancers.

Methods

A cohort of eight HPV-positive OPSCC pre-treatment patient tumors (four males and four females), were selected. All patients received a p16INK4A positive OPSCC diagnosis and were treated at the McGill University Health Centre, a quaternary center in Montreal. A minimum of 20mg of tumor tissue was used for DNA extraction. Extracted DNA was subjected to Nanopore long-read sequencing to detect and analyze for the presence of high-risk HPV sequences. PCR and Sanger sequencing experiments were performed to confirm Nanopore long-read sequencing readings.

Results

Nanopore long-read sequencing showed that seven out of eight patient samples displayed either integrated or episomal high-risk HPV sequences. Out of these seven samples, four displayed verifiable integration events upon bioinformatic analysis. Integration confirmation experiments were designed for all four samples using PCR-based methods. Sanger sequencing was also performed. Four distinct HPV integration patterns were identified: concatemer chromosomal integration in a single chromosome, bi-chromosomal concatemer integration, single chromosome complete integration and bi-chromosomal complete integration. HPV concatemer integration also proved more common than full HPV integration events.

Conclusion and relevance

Long-read sequencing technologies can be effectively used to assess HPV integration patterns in OPSCC tumors. Clinically, more research should be conducted on the prognostication value of high-risk HPV integration in OPSCC tumors using long-read sequencing technology.

Multi-region sequencing depicts intratumor heterogeneity and clonal evolution in cervical cancer

Cervical cancer is a heterogeneous malignancy mainly caused by human papillomavirus (HPV). While a few studies have revealed heterogeneity of cervical cancer in chromosome levels, the correlation between genetic heterogeneity and HPV integration in cervical cancer remains unknown. Here, we applied multi-region whole-exome sequencing and HPV integration analysis to explore intratumor heterogeneity in cervical cancer. We sequenced 20 tumor regions and 5 adjacent normal tissues from 5 cervical cancer patients, analysis based on somatic mutations and somatic copy number alterations (SCNAs) levels were performed. Variable heterogeneity was observed between the five patients with different tumor stages and HPV infection statuses. We found HPV integration has a positive effect on somatic mutation burden, but the relation to SCNAs remains unclear. Frequently mutated genes in cervical cancer were identified as trunk events, such as FBXW7, PIK3CA, FAT1 in somatic mutations and TP63, MECOM, PIK3CA, TBL1XR1 in SCNAs. New potential driver genes in cervical cancer were summarized including POU2F2, TCF7 and UBE2A. The SCNAs level has potential relation with tumor stage, and Signature 3 related to homologous recombination deficiency may be the appropriate biomarker in advanced cervical cancer. Mutation signature analysis also revealed a potential pattern that APOBEC-associated signature occurs in early stage and signatures associated with DNA damage repair arise at the later stage of cervical cancer evolution. In a conclusion, our study provides insights into the potential relationship between HPV infection and tumor heterogeneity. Those results enhanced our understanding of tumorigenesis and progression in cervical cancer.

Detection of HPV and Human Chromosome Sites by Dual-Color Fluorescence In Situ Hybridization Reveals Recurrent HPV Integration Sites and Heterogeneity in Cervical Cancer

Human papillomavirus (HPV) integration in the human genome is suggested to be an important cause of cervical cancer. With the development of sequencing technologies, an increasing number of integration “hotspots” have been identified. However, this HPV integration information was derived from analysis of whole cervical cancer tissue, and we know very little about the integration in different cancer cell subgroups or individual cancer cells. This study optimized the preparation of probes and provided a dual-color fluorescence in situ hybridization (FISH) method to detect HPV integration sites in paraffin-embedded cervical cancer samples. We used both HPV probes and site-specific probes: 3p14 (FHIT), 8q24 (MYC), 13q22 (KLF5/KLF12), 3q28 (TP63), and 5p15 (TERT). We detected HPV signals in 75 of the 96 cases of cervical cancer; 62 cases showed punctate signals, and 13 cases showed diffuse punctate signals. We identified 3p14 as a high-frequency HPV integration site in 4 cervical cancer cases. HPV integration at 8p14 occurred in 2 cases of cervical cancer. In the same cervical cancer tissue of sample No.1321, two distinct subgroups of cells were observed based on the HPV probe but showed no difference in cell and nucleus morphology. Our study provides a new method to investigate the frequent HPV integration sites in cervical cancer and reports the heterogeneity within cervical cancer from the perspective of HPV integration.

Molecular Signatures of Gynecological Cancers: Clinicians Perspective

Large-scale molecular profiling and DNA sequencing has revolutionized cancer research. Precision medicine is a rapidly developing area in cancer care but it is not uniformly applied across different tumor types. Biomarker-based therapy is associated with improved outcomes, both in terms of progression-free survival and overall survival. Comprehensive genomic profiling (CGP) uses next-generation sequencing to analyze the complete coding sequence of hundreds of genes from a small amount of tissue. Genes included in these assays are those associated with cancer development or have diagnostic, prognostic, familial, or therapeutic implications Genomic profiling is emerging as a clinically viable tool to personalize patient's treatment. This article discusses how the insights gained through CGP can impact treatment plan in common gynecological cancers.

Accurate Detection of HPV Integration Sites in Cervical Cancer Samples Using the Nanopore MinION Sequencer Without Error Correction

During the carcinogenesis of cervical cancer, the DNA of human papillomavirus (HPV) is frequently integrated into the human genome, which might be a biomarker for the early diagnosis of cervical cancer. Although the detection sensitivity of virus infection status increased significantly through the Illumina sequencing platform, there were still disadvantages remain for further improvement, including the detection accuracy and the complex integrated genome structure identification, etc. Nanopore sequencing has been proven to be a fast yet accurate technique of detecting pathogens in clinical samples with significant longer sequencing length. However, the identification of virus integration sites, especially HPV integration sites was seldom carried out by using nanopore platform. In this study, we evaluated the feasibility of identifying HPV integration sites by nanopore sequencer. Specifically, we re-sequenced the integration sites of a previously published sample by both nanopore and Illumina sequencing. After analyzing the results, three points of conclusions were drawn: first, 13 out of 19 previously published integration sites were found from all three datasets (i.e., nanopore, Illumina, and the published data), indicating a high overlap rate and comparability among the three platforms; second, our pipeline of nanopore and Illumina data identified 66 unique integration sites compared with previous published paper with 13 of them being verified by Sanger sequencing, indicating the higher integration sites detection sensitivity of our results compared with published data; third, we established a pipeline which could be used in HPV integration site detection by nanopore sequencing data without doing error correction analysis. In summary, a new nanopore data analysis method was tested and proved to be reliable in integration sites detection compared with methods of existing Illumina data analysis pipeline with less sequencing data required. It provides a solid evidence and tool to support the potential application of nanopore in virus status identification.

Identification of Specific Tumor Markers in Vulvar Carcinoma Through Extensive Human Papillomavirus DNA Characterization Using Next Generation Sequencing Method

OBJECTIVES

A subset of vulvar carcinomas (VC) are associated with human papillomavirus (HPV) DNA. This trait can be used to identify tumor markers for patient's follow-up. A large diversity of HPV prevalence in VC has been reported, but no data are available concerning the insertional HPV status in this tumor type. Therefore, we have used an innovative next generation sequencing (NGS)-based CaptHPV method able to provide an extensive characterization of HPV DNA in tumors.

MATERIAL AND METHODS

Tumor tissue specimens from 55 patients with VC were analyzed using p16 immunohistochemistry, in situ hybridization, polymerase chain reaction, and CaptHPV-NGS assays.

RESULTS

Our analyses showed that 8 (14.5%) of 55 cases were associated with HPV 16 DNA. No other HPV genotypes were identified. The HPV genome was in a free episomal state only in one case and both episomal and integrated into the tumor cell genome in 7. There was a single insertion in 5 cases and multiple sites, scattered at different chromosomal loci in two. ISH data suggest that some of these might reflect tumor heterogeneity. Viral integration targeted cellular genes among which were TP63, CCDC148, LOC100133091, PKP1, and POLA2. Viral integration at the PKP1 locus was associated with partial gene deletion, and no PKP1 protein was detected in tumor tissue.

CONCLUSIONS

Using the NGS-based innovative capture-HPV approach, we established a cartography of HPV 16 DNA in 8 VC cases and identified novel genes targeted by integration that may be used as specific tumor markers. In addition, we established a rationale strategy for optimal characterization of HPV status in VC.

Transposable Elements Cross Kingdom Boundaries and Contribute to Inflammation and Ageing: Somatic Acquisition of Foreign Transposable Elements as a Catalyst of Genome Instability, Epigenetic Dysregulation, Inflammation, Senescence, and Ageing

The de-repression of transposable elements (TEs) in mammalian genomes is thought to contribute to genome instability, inflammation, and ageing, yet is viewed as a cell-autonomous event. In contrast to mammalian cells, prokaryotes constantly exchange genetic material through TEs, crossing both cell and species barriers, contributing to rapid microbial evolution and diversity in complex communities such as the mammalian gut. Here, it is proposed that TEs released from prokaryotes in the microbiome or from pathogenic infections regularly cross the kingdom barrier to the somatic cells of their eukaryotic hosts. It is proposed this horizontal transfer of TEs from microbe to host is a stochastic, ongoing catalyst of genome destabilization, resulting in structural and epigenetic variations, and activation of well-evolved host defense mechanisms contributing to inflammation, senescence, and biological ageing. It is proposed that innate immunity pathways defend against the horizontal acquisition of microbial TEs, and that activation of this pathway during horizontal transposon transfer promotes chronic inflammation during ageing. Finally, it is suggested that horizontal acquisition of prokaryotic TEs into mammalian genomes has been masked and subsequently under-reported due to flaws in current sequencing pipelines, and new strategies to uncover these events are proposed.

High frequency of HPV16 European variant E350G among Mexican women from Sinaloa

Background & objectives:

Human papillomavirus (HPV) infections play a crucial role in the aetiology of cervical cancer (CC), and HPV16 is the primary viral genotype associated with CC. A number of variants of the HPV16 E6 gene are involved in the progression of CC, differing in their prevalence and biological and biochemical properties. This study was designed to determine the frequency of HPV types 16/18 and to identify the presence of HPV16 E6-variants in asymptomatic Mexican women.

Methods:

A total of 189 cervical Pap smears were collected from women attending public health services in three different cities in Sinaloa, Mexico. Viral DNA was identified by amplification of E6 viral gene fragments using polymerase chain reaction (PCR). Identification of variants was done by sequencing a DNA fragment (321bp) of the HPV16 E6 gene.

Results:

More than half of the women tested were HPV-positive (52.38%), with HPV16 being the most frequent genotype (21.16%), followed by HPV18 (8.99%). Sequence analysis of the E6-HPV16 PCR products showed that in all cases, the viruses corresponded to European variants. It was further observed that the E350G intra-variant was the most common (>76%).

Interpretation & conclusions:

This study showed a predominance of European lineage variants of HPV16 among asymptomatic women from Sinaloa, Mexico, predominantly with of the E350G variant. This variant has been shown to be associated with an increased risk of early development of CC. The use of molecular identification of carcinogenic HPV and Pap test screening may be a good strategy for monitoring women to prevent CC.

The precision prevention and therapy of HPV-related cervical cancer: new concepts and clinical implications

Cervical cancer is the third most common cancer in women worldwide, with concepts and knowledge about its prevention and treatment evolving rapidly. Human papillomavirus (HPV) has been identified as a major factor that leads to cervical cancer, although HPV infection alone cannot cause the disease. In fact, HPV-driven cancer is a small probability event because most infections are transient and could be cleared spontaneously by host immune system. With persistent HPV infection, decades are required for progression to cervical cancer. Therefore, this long time window provides golden opportunity for clinical intervention, and the fundament here is to elucidate the carcinogenic pattern and applicable targets during HPV-host interaction. In this review, we discuss the key factors that contribute to the persistence of HPV and cervical carcinogenesis, emerging new concepts and technologies for cancer interventions, and more urgently, how these concepts and technologies might lead to clinical precision medicine which could provide prediction, prevention, and early treatment for patients.

Nuclear factor I X is a recurrent target for HPV16 insertions in anal carcinomas

Anal carcinomas (AC) are associated with human papillomavirus (HPV) DNA sequences, but little is known about the physical state of the viral genome in carcinoma cells. To define the integration status and gene(s) targeted by viral insertions in AC, tumor DNAs extracted from 35 tumor specimen samples in patients with HPV16-associated invasive carcinoma were analyzed using the detection of integrated papillomavirus sequences-PCR approach. The genomic status at integration sites was assessed using comparative genomic hybridization-array assay and gene expression using reverse transcription quantitative PCR (RT-qPCR). HPV16 DNA was found integrated in 25/35 (71%) cases and the integration locus could be determined at the molecular level in 19 cases (29 total integration loci). HPV DNA was inserted on different chromosomes, but 5 cases harbored viral sequences at 19p13.2, within the nuclear factor I X (NFIX) locus. Viral DNA mapped between the most distal and the two proximal alternatively expressed exons of this gene in three cases (CA21, CA04, and CA35) and upstream of this gene (663 kb and 2.3 Mb) in the others. CGH arrays showed genomic gains/amplifications at the NFIX region, associated with HPV within the gene and RT-qPCR, revealed NFIX mRNA overexpression. Other genes targeted by integration were IL20RB, RPS6KA2, MSRA1, PIP5K1B, SLX4IP, CECR1, BCAR3, ATF6, CSNK1G1, APBA2, AGK, ILF3, PVT1, TRMT1, RAD51B, FASN, CCDC57, DSG3, and ZNF563. We identified recurrent targeting of NFIX by HPV16 insertion in anal carcinomas, supporting a role for this gene in oncogenesis, as reported for non-HPV tumors.

Microbes involving in carcinogenesis; growing state of the art

Lateral gene transfer (LGT) has been demonstrated as a transfer process of novel genes between different species. LGT proceedings are occurring between microbes and plants, as well as between microbes and animals. New evidence demonstrates that bacterial insertional mutagenesis may occur in cancer cells. Due to the important role of genetic changes in the increase of cell proliferation and cancer development, we reviewed the effects of microbial-animal LGT in human oncogenesis. In addition, viral DNA can induce cancer development by random insertion into cancer-related genes or by inducing translocations. In conclusion, growing evidence shows the contribution of the microbial genome in cancer and autoimmune disease.

HGT-ID: an efficient and sensitive workflow to detect human-viral insertion sites using next-generation sequencing data

Background

Transfer of genetic material from microbes or viruses into the host genome is known as horizontal gene transfer (HGT). The integration of viruses into the human genome is associated with multiple cancers, and these can now be detected using next-generation sequencing methods such as whole genome sequencing and RNA-sequencing.

Results

We designed a novel computational workflow, HGT-ID, to identify the integration of viruses into the human genome using the sequencing data. The HGT-ID workflow primarily follows a four-step procedure: i) pre-processing of unaligned reads, ii) virus detection using subtraction approach, iii) identification of virus integration site using discordant and soft-clipped reads and iv) HGT candidates prioritization through a scoring function. Annotation and visualization of the events, as well as primer design for experimental validation, are also provided in the final report. We evaluated the tool performance with the well-understood cervical cancer samples. The HGT-ID workflow accurately detected known human papillomavirus (HPV) integration sites with high sensitivity and specificity compared to previous HGT methods. We applied HGT-ID to The Cancer Genome Atlas (TCGA) whole-genome sequencing data (WGS) from liver tumor-normal pairs. Multiple hepatitis B virus (HBV) integration sites were identified in TCGA liver samples and confirmed by HGT-ID using the RNA-Seq data from the matched liver pairs. This shows the applicability of the method in both the data types and cross-validation of the HGT events in liver samples. We also processed 220 breast tumor WGS data through the workflow; however, there were no HGT events detected in those samples.

Conclusions

HGT-ID is a novel computational workflow to detect the integration of viruses in the human genome using the sequencing data. It is fast and accurate with functions such as prioritization, annotation, visualization and primer design for future validation of HGTs. The HGT-ID workflow is released under the MIT License and available at http://kalarikrlab.org/Software/HGT-ID.html.

Retinoic acid receptor beta promoter methylation and risk of cervical cancer

Cervical cancer is one of the leading causes of death in women worldwide, particularly in developing countries. Human papillomavirus has been reported as one of the key etiologic factors in cervical carcinoma. Likewise, epigenetic aberrations have ability to regulate cancer pathogenesis and progression. Recent research suggested that methylation has been detected already at precancerous stages, which methylation markers may have significant value in cervical cancer screening. The retinoic acid receptor beta (RARβ) gene, a potential tumor suppressor gene, is usually expressed in normal epithelial tissue. Methylation of CpG islands in the promoter region of the RARβ gene has been found to be associated with the development of cervical cancer. To investigate whether RARβ methylation is a potential biomarker that predicts the progression of invasive cancer, we reviewed 14 previously published articles related to RARβ methylation. The majority of them demonstrated that the frequency of RARβ promoter methylation was significantly correlated with the severity of cervical epithelium abnormalities. However, methylation of a single gene may not represent the best approach for predicting disease prognosis. Analyzing combinations of aberrant methylation of multiple genes may increase the sensitivity, and thus this approach may serve as a better tool for predicting disease prognosis.

Analysis of human papilloma virus type 52 integration status in exfoliated cervical cells

To explore the significance of human papilloma virus type 52 (HPV52) infection and its integration in cells within cervical lesions, the expression levels of HPV52 were detected using polymerase chain reaction (PCR). The copy numbers of HPV52 E2, HPV52 E6 and the reference gene β-actin were determined by quantitative PCR to analyze the association between HPV52 integration and cervical lesions. HPV52 integration was analyzed by the amplification of papillomavirus oncogene transcripts. A total of 13 samples from 468 cases were positive for HPV52. Among the samples, 1 case with an E2/E6 ratio >1 was purely episomal, 3 cases with an E2/E6 ratio of 0 were purely integrated, and 9 cases with an E2/E6 ratio of between 0 and 1 were a mixture of integrated and episomal. With the progression of cervical disease, the prevalence of the episomal type decreased gradually, and the prevalence of the integrated (episomal and integrated) forms increased. The pure integration of HPV52 occurred in chromosomes 2, 5 and 8. These results indicate that HPV52 integration into the host genome may be a key factor in cervical lesions. Thus, patients at high risk for cervical lesions may potentially be identified by screening for HPV52 infection and integration.

Methylation of the L1 gene and integration of human papillomavirus 16 and 18 in cervical carcinoma and premalignant lesions

High-risk human papillomavirus (HPV) is the primary cause of cervical carcinoma (CC). Viral integration into the host chromosomes is associated with neoplastic progression, and epigenetic changes may occur as a result. The objective of the present study was to analyze HPV L1 gene methylation and to compare the use of quantitative polymerase chain reaction (qPCR), in situ hybridization (ISH) and L1 methylation analysis as methods for detecting HPV integration. Cervical scrapes or biopsy samples positive for HPV 16 or 18, from 187 female patients with CC, squamous intraepithelial lesions (SILs) or no intraepithelial lesion (non-IL) were analyzed. Methylation of the L1 gene was determined using bisulfite modification followed by PCR, and HPV integration was subsequently analyzed. HPV 16 L1 gene methylation was revealed to increase with histological grade, with statistically significant differences observed as follows: Low-grade SIL vs. CC, P<0.0001 and non-IL vs. CC, P<0.0001. HPV 18 L1 gene methylation also increased according to histological grade, however, no statistically significant differences were observed. Methylation at CpG site 5608 of the HPV 16 L1 gene was associated with all grades of cervical lesions, whereas methylation at CpG site 5617 demonstrated the strongest association with CC (odds ratio, 42.5; 95% confidence interval, 4.7-1861; P<0.0001). The concordance rates between the various methods for the detection of the physical status of HPV 16 and HPV 18 were 96.1% for qPCR and ISH, 76.7% for qPCR and L1 gene methylation, and 84.8% for ISH and L1 gene methylation. In conclusion, methylation of the HPV 16 L1 gene increases significantly according to the grade of the cervical lesion, and methylation at CpG sites 5608 and 5617 of this gene may be used as prognostic biomarkers. ISH and L1 gene methylation have good concordance with qPCR with regards to the detection of HPV integration. Therefore, these are useful methods in determining the physical state of HPV.

HPV Integration in HNSCC Correlates with Survival Outcomes, Immune Response Signatures, and Candidate Drivers

The incidence of human papillomavirus (HPV)-related oropharynx cancer has steadily increased over the past two decades and now represents a majority of oropharyngeal cancer cases. Integration of the HPV genome into the host genome is a common event during carcinogenesis that has clinically relevant effects if the viral early genes are transcribed. Understanding the impact of HPV integration on clinical outcomes of head and neck squamous cell carcinoma (HNSCC) is critical for implementing deescalated treatment approaches for HPV⁺ HNSCC patients. RNA sequencing (RNA-seq) data from HNSCC tumors (n = 84) were used to identify and characterize expressed integration events, which were overrepresented near known head and neck, lung, and urogenital cancer genes. Five genes were recurrent, including CD274 (PD-L1) A significant number of genes detected to have integration events were found to interact with Tp63, ETS, and/or FOX1A. Patients with no detected integration had better survival than integration-positive and HPV^- patients. Furthermore, integration-negative tumors were characterized by strongly heightened signatures for immune cells, including CD4⁺, CD3⁺, regulatory, CD8⁺ T cells, NK cells, and B cells, compared with integration-positive tumors. Finally, genes with elevated expression in integration-negative specimens were strongly enriched with immune-related gene ontology terms, while upregulated genes in integration-positive tumors were enriched for keratinization, RNA metabolism, and translation.Implications: These findings demonstrate the clinical relevancy of expressed HPV integration, which is characterized by a change in immune response and/or aberrant expression of the integration-harboring cancer-related genes, and suggest strong natural selection for tumor cells with expressed integration events in key carcinogenic genes. Mol Cancer Res; 16(1); 90-102. ©2017 AACR.

Effect of p53 codon 72 polymorphism on the survival outcome in advanced stage cervical cancer patients in India

Background & objectives:

The Arg>Pro polymorphism in codon 72 of p53 gene is known to affect the susceptibility of cervical cancer differently in different population worldwide although information regarding its role in determining survival status and disease outcome in patients is lacking. The present study was conducted to determine the genotype frequency and prognostic role of p53 codon 72 Arg>Pro polymorphism in patients with advanced stage cervical cancer in India.

Methods:

The p53 codon 72 polymorphism was determined in tumour biopsies (n = 107) and matched blood samples (n = 19) in cervical cancer patients using polymerase chain reaction-restriction fragment length polymorphism method (PCR-RFLP). Effect of p53 genotype on the overall survival (OS) and recurrence-free survival (RFS) was analyzed. Individual Arg or Pro alleles were studied for their significance on survival as Pro carriers (Pro/Pro + Arg/Pro) versus Arg/Arg individuals or Arg carriers (Arg/Arg + Arg/Pro) versus Pro/Pro individuals.

Results:

The frequencies for Arg/Arg, Arg/Pro and Pro/Pro genotypes were 27.2, 49.5 and 23.3 per cent, respectively. There was no significant difference in the genotypes with respect to patients’ OS or RFS.

Interpretation & conclusions:

The findings of our study indicated that p53 codon 72 polymorphism might not be an independent marker in predicting clinical outcome in advanced stage cervical cancer patients. Further studies need to be done in larger samples to confirm these findings.

RNA extraction method is crucial for human papillomavirus E6/E7 oncogenes detection

BACKGROUND

Human papillomavirus (HPV) DNA testing plays a main role in the management of cervical cancer, however to improve the specificity in cervical screening, there is a need to develop and validate different approaches that can identify women at risk for progressive disease. Nowadays, mRNA expression of viral E6 and E7 HPV oncogenes stands up as a potential biomarker to improve cervical screening. We aimed to validate a method for RNA extraction, detect HPV mRNA expression and, assess the relationship between E6/E7 mRNA expression and pathology of patients' lesions and progression.

METHODS

This study included 50 specimens that had been previously genotyped as HPV16, 18, 31, 33 and/or 45. Cervical swabs were extracted with three different RNA extraction methods -Nuclisens manual extraction kit (bioMérieux), High Pure Viral RNA Kit (Roche) and RNeasy Plus Mini kit (Qiagen)-, and mRNA was detected with NucliSens EasyQ HPV version 1 test (bioMérieux) afterwards. Association of oncogene expression with pathology and lesion progression was analyzed for each extraction method.

RESULTS

E6/E7 mRNA positivity rate was higher in samples analyzed with bioMérieux (62%), followed by Roche (24%) and Qiagen (6%). Women with lesions and lesion progression showed a higher prevalence of viral RNA expression than women that had not lesions or with lesion persistence. While bioMérieux revealed a higher sensitivity (77.27%), Roche presented a higher PPV (75%) and an increased specificity (89.28%).

CONCLUSIONS

Extraction methods based on magnetic beads provided better RNA yield than those based in columns. Both Nuclisens manual extraction kit (bioMérieux) and High Pure Viral RNA Kit (Roche) seemed to be adequate for E6/E7 mRNA detection. However, none of them revealed both high sensitivity and specificity values. Further studies are needed to obtain and validate a standard gold method for RNA expression detection, to be included as part of the routine cervical screening program.

miR-3156-3p is downregulated in HPV-positive cervical cancer and performs as a tumor-suppressive miRNA

Background

Cervical cancer (CC) is the second most common cancer in females in developing countries. The two viral oncoproteins E6 and E7 mediate the oncogenic activities of high-risk human papillomavirus (HR-HPV), and HR-HPV, especially HPV16 or/and HPV18 (HPV16/18) play critical roles in CC through different pathways. microRNAs (miRNAs) may be associated with CC pathogenesis. Researches have indicated that human papillomavirus (HPV) may regulate cellular miRNA expression through viral E6 and E7. Herein, the purposes of this study were to identify the relationship between HPV infection and aberrantly expressed miRNAs and to investigate their pathogenic roles in CC.

Methods

miRNA expression was assessed using a microRNAs microarray in HPV16 E6- and E7-integrated HPV-negative HT-3 cell lines and mock vector-transfected HT-3 cells. The microarray results were validated, and the expression of miR-3156-3p was identified in HPV-positive and -negative CC cell lines as well as primary CC and normal cervical epithelium tissues using quantitative reverse-transcription polymerase chain reaction (qRT-PCR). Cell Counting Kit-8 (CCK8), flow cytometry, transwell analysis, tube formation, and Western blotting were used to identify the functional role of miR-3156-3p in CaSki, SiHa, and HeLa cell lines.

Results

Six underexpressed microRNAs (miR-3156-3p, 6779-3p, 4779-3p, 6841-3p, 454-5p and 656-5p) were consistently identified in HPV16 E6- and E7-integrated HT-3 cells. Further investigation confirmed a significant decrease of miR-3156-3p in HPV16/18 positive CC lesions. CCK8, flow cytometry, transwell analysis, tube formation assays, and Western blotting of the CC cell lines with miR-3156-3p over/under-expression in vitro showed that miR-3156-3p was involved in cell proliferation, apoptosis, migration, neovascularization, and SLC6A6 regulation.

Conclusions

Our findings indicate that miR-3156-3p plays a suppressor-miRNA role in CC and that its expression is associated with HR-HPV infection.

Somatic Variations in Cervical Cancers in Indian Patients

There are very few reports that describe the mutational landscape of cervical cancer, one of the leading cancers in Indian women. The aim of the present study was to investigate the somatic mutations that occur in cervical cancer. Whole exome sequencing of 10 treatment naïve tumour biopsies with matched blood samples, from a cohort of Indian patients with locally advanced disease, was performed. The data revealed missense mutations across 1282 genes, out of 1831 genes harbouring somatic mutations. These missense mutations (nonsynonymous + stop-gained) when compared with pre-existing mutations in the COSMIC database showed that 272 mutations in 250 genes were already reported although from cancers other than cervical cancer. More than 1000 novel somatic variations were obtained in matched tumour samples. Pathways / genes that are frequently mutated in various other cancers were found to be mutated in cervical cancers. A significant enrichment of somatic mutations in the MAPK pathway was observed, some of which could be potentially targetable. This is the first report of whole exome sequencing of well annotated cervical cancer samples from Indian women and helps identify trends in mutation profiles that are found in an Indian cohort of cervical cancer.

Human papillomavirus (HPV) genome status & cervical cancer outcome--A retrospective study

Background & objectives:

Persistent infections with high-risk (HR) human papillomaviruses such as HPV 16, 18, 31, 33 and 45 have been identified as the major aetiological factor for cervical cancer. The clinical outcome of the disease is often determined by viral factors such as viral load, physical status and oncogene expression. The aim of the present study was to evaluate the impact of such factors on clinical outcome in HPV16 positive, locally advanced cervical cancer cases.

Methods:

One hundred and thirty two pretreatment cervical tumour biopsies were selected from patients undergoing radiotherapy alone (n=63) or concomitant chemo-radiation (n=69). All the samples were positive for HPV 16. Quantitative real time-PCR was carried out to determine viral load and oncogene expression. Physical status of the virus was determined for all the samples by the ratio of E2_copies/E7_copies; while in 73 cases, the status was reanalyzed by more sensitive APOT (amplification of papillomavirus oncogene transcripts) assay. Univariate analysis of recurrence free survival was carried out using Kaplan-Meier method and for multivariate analysis the Cox proportional hazard model was used.

Results:

The median viral load was 19.4 (IQR, 1.9- 69.3), with viral integration observed in 86 per cent cases by combination of the two methodologies. Both univariate and multivariate analyses identified viral physical status as a good predictor of clinical outcome following radiation treatment, with episomal form being associated with increased recurrence free survival.

Interpretation & conclusions:

The present study results showed that viral physical status might act as an important prognostic factor in cervical cancer.

The negative conversion of high-risk human papillomavirus and its performance in surveillance of cervical cancer after treatment: a retrospective study

PURPOSE

To determine the negative conversion regularity of high-risk human papillomavirus (HR-HPV) and to evaluate the prognostic implications of HR-HPV testing in patients with cervical cancer after treatment.

METHODS

A retrospective post-treatment analysis of 173 patients with cervical cancer was performed from January 2011 to December 2012. Patients who had HR-HPV infection before treatment were included. Clinical and pathological characteristics, as well as follow-up information, were reviewed.

RESULTS

The negative conversion rate of HR-HPV reached 68.9 % within half a year and increased most rapidly within the first 2 years after treatment. Univariate and multivariate analyses suggested that the negative conversion rate of HR-HPV was significantly correlated with clinical stage, treatment regimens, and HR-HPV type (P < 0.05). In our analysis of 173 patients, we found that HR-HPV status was predictive of 3-year survival rate and disease recurrence (P < 0.05). Pelvic recurrence, but not distant metastasis, was influenced by HR-HPV status (P < 0.05). Through 2 × 2 table analysis, we found that HR-HPV was more sensitive (71.43 %) and specific (94.20 %) than cervical cytology (sensitivity 62.86 % and specificity 78.26 %).

CONCLUSIONS

The negative conversion rate of HR-HPV increased most rapidly within the first 2 years of cervical cancer surveillance. Persistent HPV infection was associated with a poor prognosis and had an impact on recurrence sites. Further large and multi-center prospective studies should be performed, but these results of this study suggested that HR-HPV monitoring is necessary to be used as a means of cervical cancer surveillance.

Genomic characterization of viral integration sites in HPV-related cancers

Persistent infection with carcinogenic human papillomaviruses (HPV) causes the majority of anogenital cancers and a subset of head and neck cancers. The HPV genome is frequently found integrated into the host genome of invasive cancers. The mechanisms of how it may promote disease progression are not well understood. Thoroughly characterizing integration events can provide insights into HPV carcinogenesis. Individual studies have reported limited number of integration sites in cell lines and human samples. We performed a systematic review of published integration sites in HPV-related cancers and conducted a pooled analysis to formally test for integration hotspots and genomic features enriched in integration events using data from the Encyclopedia of DNA Elements (ENCODE). Over 1,500 integration sites were reported in the literature, of which 90.8% (N = 1,407) were in human tissues. We found 10 cytobands enriched for integration events, three previously reported ones (3q28, 8q24.21 and 13q22.1) and seven additional ones (2q22.3, 3p14.2, 8q24.22, 14q24.1, 17p11.1, 17q23.1 and 17q23.2). Cervical infections with HPV18 were more likely to have breakpoints in 8q24.21 (p = 7.68 × 10(-4) ) than those with HPV16. Overall, integration sites were more likely to be in gene regions than expected by chance (p = 6.93 × 10(-9) ). They were also significantly closer to CpG regions, fragile sites, transcriptionally active regions and enhancers. Few integration events occurred within 50 Kb of known cervical cancer driver genes. This suggests that HPV integrates in accessible regions of the genome, preferentially genes and enhancers, which may affect the expression of target genes.

E1 detection as prognosticator in human papillomavirus-positive head and neck cancers

PURPOSE

HPV-related locally advanced head and neck cancers (LA-HNCs) show a good prognosis. This study aimed to investigate the HPV prevalence in LA-HNCs and compare the prognostic value of E1, E6 and L1 genomic viral fragments and p16, individually and in combination, in order to find the best prognosticator in terms of overall survival (OS) and progression-free survival (PFS).

PATIENTS AND METHODS

HPV16 was searched in 255 LA-HNC formalin-fixed paraffin-embedded tumor tissues, 89 oropharyngeal cancers (OPCs), and 166 non-OPCs by DNA-PCR with 3 primer pairs. p16 was analyzed by immunohistochemistry in 235 patients.

RESULTS

The prevalence of positive samples decreased constantly from E6 to L1 and E1 in both OPCs and non-OPCs. Each LA-HNC patient highlighted variable positivity for each fragment. OPCs showed a higher prevalence of positive samples compared to non-OPCs.Positive coexistence of all the fragments was more common in OPCs (31.5%) than non-OPCs (4.2%), and E1 detection was always associated with E6 and L1. E1-positive OPCs showed improved OS (p = 0.012) and PFS (p = 0.036), while L1- or E6-positive ones did not. p16-positive patients were more prevalent in the OPC (29.8%) than the non-OPC group (7.3%) (p&lt;0.0001) and its prognostic value was not superior to that of E1. However, the multivariate Cox analysis which included E1, L1, E6 status and p16 expression did not show a significant p value.

CONCLUSIONS

Though HPV16 positivity measured by DNA-PCR was higher for L1 and E6, they performed weakly as prognosticators; E1 might become a strong prognostic marker for OS and PFS in OPCs.

The protective role of the -1306C>T functional polymorphism in matrix metalloproteinase-2 gene is associated with cervical cancer: implication of human papillomavirus infection

Cervical cancer is the major reproductive health problem among women caused by persistent infection of high-risk human papillomavirus (HR-HPV). Metalloproteinase-2 (MMP-2) is an endopeptidase highly expressed in cervical cancer; however, the genetic link between aberrant expression of MMP-2 and cervical carcinogenesis is not known. The genotypic distribution, expression pattern of MMP-2 and HPV infection, was analyzed in a total of 300 fresh surgically resected cervical tissue biopsies. The MMP-2 C1306T (rs243865) promoter polymorphism dominant model (CC v/s CT + CT + TT) revealed that the CC genotype had a 4.33-fold significant increased risk for development of cervical cancer (OR = 4.33; 95 % CI = 2.36-4.02, p = 0.0001) compared to those with variant genotypes (-1306 CT + TT). The C allele was associated with 3-fold significant increased risk (OR = 2.95; 95 % CI = 1.90-4.60, p = 0.0002) compared to T allele. Interestingly, a significant correlation was found between high expression of MMP-2 protein and CC genotype in cancer patients (p = 0.001) compared to normal controls (p = 0.012). Further analysis showed that the risk of cancer was extremely pronounced in HPV positive patients (OR = 9.33; 95 % CI = 2.88-30.20, p = 0.0001) compared to HPV negative ones, implicating the possible interaction between -1306CC genotype and HPV infection in increasing the cancer risk (p = 0.0001). The leads from the present study suggest the protective role of gene variant -1306C>T at the promoter region of the MMP-2 against HPV-mediated cervical cancer. These findings substantiate the functional role of MMP-2 C1306T polymorphism in a significant downregulation of MMP-2 protein in women with variant genotype (CT/TT) compared to the normal wild CC genotype.

Simultaneous detection of human papillomavirus integration and c-MYC gene amplification in cervical lesions: an emerging marker for the risk to progression

PURPOSE

The persistence of high-risk oncogenic human papillomavirus (HR-HPV) infection and its integration into the host genome are key steps in the induction of malignant alterations. c-MYC chromosome region is a frequent localization for HPV insertion that has been observed in chromosome band 8q24 by fluorescence in situ hybridization (FISH). We report the HPV viral integration and amplification patterns of the c-MYC gene in cytological smears with FISH as a potential biomarker for the progression of squamous intraepithelial lesions (SIL).

METHODS

HPV detection and genotyping by polymerase chain reaction (PCR) and FISH analysis by "Vysis Cervical FISH Probe" kit (ABBOTT Molecular Inc.) were performed in 37 cervical samples including 8 NILM, 7 ASC-US, 7 LSIL, 3 ASC-H, 7 HSIL and 5 SCC.

RESULTS

The results show concordance between FISH and PCR techniques for HPV detection. The majority of the samples contained HR-HPV, the majority being -16 and -18 genotypes. HPV integration as determined by FISH was most frequent in high-risk lesions. The c-MYC gene amplification was found only in HPV-positive samples and was detected primarily in high-risk lesions and in cells with an integrated form of HPV.

CONCLUSIONS

HPV integration and c-MYC gene amplification detected by FISH could be an important biomarker for use in clinical practice to determine SIL with a risk of progression.

Human papillomavirus (HPV) screening and cervical cancer burden. A Brazilian perspective

This review tackles the issues related to disease burden caused by cervical cancer (CC) and its precursor (CIN) lesions in Brazil. A special focus is given to new technologies with potential to interfere with the development of CC by reducing the high-risk human papillomavirus (hr-HPV)-induced lesions that remain a major public health burden in all developing countries where organized screening programs do not exist. Globally, 85 % of all incident CC and 50 % of CC deaths occur in the developing countries. Unfortunately, most regions of Brazil still demonstrate high mortality rates, ranking CC as the second most common cancer among Brazilian women. Recently, CC screening programs have been tailored in the country to enable early detection of CC precursor lesions and thereby reduce cancer mortality. A combination of HPV testing with liquid-based cytology (LBC) seems to be a promising new approach in CC screening, with high expectation to offer an adequate control of CC burden in this country.

NGS-based approach to determine the presence of HPV and their sites of integration in human cancer genome

BACKGROUND

Human papilloma virus (HPV) accounts for the most common cause of all virus-associated human cancers. Here, we describe the first graphic user interface (GUI)-based automated tool 'HPVDetector', for non-computational biologists, exclusively for detection and annotation of the HPV genome based on next-generation sequencing data sets.

METHODS

We developed a custom-made reference genome that comprises of human chromosomes along with annotated genome of 143 HPV types as pseudochromosomes. The tool runs on a dual mode as defined by the user: a 'quick mode' to identify presence of HPV types and an 'integration mode' to determine genomic location for the site of integration. The input data can be a paired-end whole-exome, whole-genome or whole-transcriptome data set. The HPVDetector is available in public domain for download: http://www.actrec.gov.in/pi-webpages/AmitDutt/HPVdetector/HPVDetector.html.

RESULTS

On the basis of our evaluation of 116 whole-exome, 23 whole-transcriptome and 2 whole-genome data, we were able to identify presence of HPV in 20 exomes and 4 transcriptomes of cervical and head and neck cancer tumour samples. Using the inbuilt annotation module of HPVDetector, we found predominant integration of viral gene E7, a known oncogene, at known 17q21, 3q27, 7q35, Xq28 and novel sites of integration in the human genome. Furthermore, co-infection with high-risk HPVs such as 16 and 31 were found to be mutually exclusive compared with low-risk HPV71.

CONCLUSIONS

HPVDetector is a simple yet precise and robust tool for detecting HPV from tumour samples using variety of next-generation sequencing platforms including whole genome, whole exome and transcriptome. Two different modes (quick detection and integration mode) along with a GUI widen the usability of HPVDetector for biologists and clinicians with minimal computational knowledge.

Genome-wide profiling of HPV integration in cervical cancer identifies clustered genomic hot spots and a potential microhomology-mediated integration mechanism

Human papillomavirus (HPV) integration is a key genetic event in cervical carcinogenesis. By conducting whole-genome sequencing and high-throughput viral integration detection, we identified 3,667 HPV integration breakpoints in 26 cervical intraepithelial neoplasias, 104 cervical carcinomas and five cell lines. Beyond recalculating frequencies for the previously reported frequent integration sites POU5F1B (9.7%), FHIT (8.7%), KLF12 (7.8%), KLF5 (6.8%), LRP1B (5.8%) and LEPREL1 (4.9%), we discovered new hot spots HMGA2 (7.8%), DLG2 (4.9%) and SEMA3D (4.9%). Protein expression from FHIT and LRP1B was downregulated when HPV integrated in their introns. Protein expression from MYC and HMGA2 was elevated when HPV integrated into flanking regions. Moreover, microhomologous sequence between the human and HPV genomes was significantly enriched near integration breakpoints, indicating that fusion between viral and human DNA may have occurred by microhomology-mediated DNA repair pathways. Our data provide insights into HPV integration-driven cervical carcinogenesis.

Mobile elements and viral integrations prompt considerations for bacterial DNA integration as a novel carcinogen

Insertional mutagenesis has been repeatedly demonstrated in cancer genomes and has a role in oncogenesis. Mobile genetic elements can induce cancer development by random insertion into cancer related genes or by inducing translocations. L1s are typically implicated in cancers of an epithelial cell origin, while Alu elements have been implicated in leukemia as well as epithelial cell cancers. Likewise, viral infections have a significant role in cancer development predominantly through integration into the human genome and mutating or deregulating cancer related genes. Human papilloma virus is the best-known example of viral integrations contributing to carcinogenesis. However, hepatitis B virus, Epstein-Barr virus, and Merkel cell polyomavirus also integrate into the human genome and disrupt cancer related genes. Thus far, the role of microbes in cancer has primarily been attributed to mutations induced through chronic inflammation or toxins, as is the case with Helicobacter pylori and enterotoxigenic Bacteroides fragilis. We hypothesize that like mobile elements and viral DNA, bacterial and parasitic DNA may also integrate into the human somatic genome and be oncogenic. Until recently it was believed that bacterial DNA could not integrate into the human genome, but new evidence demonstrates that bacterial insertional mutagenesis may occur in cancer cells. Although this work does not show causation between bacterial insertions and cancer, it prompts more research in this area. Promising new sequencing technologies may reduce the risk of artifactual chimeric sequences, thus diminishing some of the challenges of identifying novel insertions in the somatic human genome.

Papillomavirus genomes associate with BRD4 to replicate at fragile sites in the host genome

It has long been recognized that oncogenic viruses often integrate close to common fragile sites. The papillomavirus E2 protein, in complex with BRD4, tethers the viral genome to host chromatin to ensure persistent replication. Here, we map these targets to a number of large regions of the human genome and name them Persistent E2 and BRD4-Broad Localized Enrichments of Chromatin or PEB-BLOCs. PEB-BLOCs frequently contain deletions, have increased rates of asynchronous DNA replication, and are associated with many known common fragile sites. Cell specific fragile sites were mapped in human C-33 cervical cells by FANCD2 ChIP-chip, confirming the association with PEB-BLOCs. HPV-infected cells amplify viral DNA in nuclear replication foci and we show that these form adjacent to PEB-BLOCs. We propose that HPV replication, which hijacks host DNA damage responses, occurs adjacent to highly susceptible fragile sites, greatly increasing the chances of integration here, as is found in HPV-associated cancers.

Papillomavirus cause persistent, but mostly self-limiting, infections of the host epithelium. However, a subset of oncogenic papillomaviruses is the causative agent of certain human cancers. In persistent infection the viral genomes are tethered to host chromosomes to maintain and partition the extrachromosomal viral genomes to daughter cells. However, in cancers viral DNA is often found integrated close to common fragile sites, regions prone to breakage, amplification and deletion. We show that the viral E2 and cellular BRD4 proteins are associated with fragile regions of the human genome and nucleate viral replication foci at these sites. This is a resourceful strategy for a virus that uses the host DNA damage response to amplify viral DNA. However, the outcome may be increased accidental integration of viral DNA, which in the case of the oncogenic viruses can promote carcinogenesis.

Human papilloma virus, DNA methylation and microRNA expression in cervical cancer (Review)

Cancer is a complex disease caused by genetic and epigenetic abnormalities that affect gene expression. The progression from precursor lesions to invasive cervical cancer is influenced by persistent human papilloma virus (HPV) infection, which induces changes in the host genome and epigenome. Epigenetic alterations, such as aberrant miRNA expression and changes in DNA methylation status, favor the expression of oncogenes and the silencing of tumor-suppressor genes. Given that some miRNA genes can be regulated through epigenetic mechanisms, it has been proposed that alterations in the methylation status of miRNA promoters could be the driving mechanism behind their aberrant expression in cervical cancer. For these reasons, we assessed the relationship among HPV infection, cellular DNA methylation and miRNA expression. We conclude that alterations in the methylation status of protein-coding genes and various miRNA genes are influenced by HPV infection, the viral genotype, the physical state of the viral DNA, and viral oncogenic risk. Furthermore, HPV induces deregulation of miRNA expression, particularly at loci near fragile sites. This deregulation occurs through the E6 and E7 proteins, which target miRNA transcription factors such as p53.

Ménage à trois: an evolutionary interplay between human papillomavirus, a tumor, and a woman

Cervical cancer is the third most common cancer in women with human papillomavirus (HPV) being a key etiologic factor of this devastating disease. In this article, we describe modern advances in the genomics and transcriptomics of cervical cancer that led to uncovering the key gene drivers. We also introduce, herein, a model of cervical carcinogenesis that explains how the interplay between virus, tumor, and woman results in the selection of clones that simultaneously harbor genomic amplifications for genes that drive cell cycle, antiviral response, and inhibit cell differentiation. The new model may help researchers understand the controversies in antiviral therapy and immunogenetics of this cancer and may provide a basis for future research directions in early diagnostics and personalization of therapy.

Mate pair sequencing of oropharyngeal squamous cell carcinomas reveals that HPV integration occurs much less frequently than in cervical cancer

BACKGROUND

Human papillomavirus (HPV) is now recognized to be very important in the pathogenesis of oropharyngeal squamous cell carcinoma (OPSCC). It is not clear yet whether the physical status of HPV in OPSCC is similar to what is found in cervical cancer.

STUDY DESIGN

We performed genome-wide mate pair next generation sequencing from 20 OPSCCs patients, thirteen of which were positive for HPV16 to determine the HPV physical status and its relationship to HPV oncogene E6 and E7 expression.

RESULTS

This high throughput approach detected HPV integration events and also determined the bridged HPV coverage in each sample. Two of the HPV16-positive OPSCCs had HPV integration and one of the HPV16-negative OPSCCs had an HPV26 integration. We mapped the site of integration in the HPV genome in all integration events and the integrations were located at E1, E5, E6 and L2 region respectively. One HPV positive OPSCC had two integration events but also had a very high bridged HPV coverage, while the other two just had HPV integrated into the human genome.

CONCLUSION

Our results are thus different from what is routinely observed in cervical cancer where HPV is almost always integrated into the human genome with loss of episomal HPV sequences. Thus more investigation should be carried out to study how episomal HPV alone can contribute to the development of most OPSCCs.

Human papillomavirus genotyping and integration in ovarian cancer Saudi patients

Background

Human papillomavirus (HPV) is associated with different malignancies but its role in the pathogenesis of ovarian cancer is controversial. This study investigated the prevalence, genotyping and physical state of HPV in ovarian cancer Saudi patients.

Methods

Hundred formalin fixed paraffin embedded (FFPE) ovarian carcinoma tissues and their normal adjacent tissues (NAT) were included in the study. HPV was detected by nested polymerase chain reaction (PCR) using degenerated HPVL1 consensus primer pairs MY09/MY11 and GP5+/GP6 + to amplify a broad spectrum of HPV genotypes in a single reaction. The HPV positive samples were further genotyped using DNA sequencing. The physical state of the virus was identified using Amplification of Papillomavirus Oncogene Transcripts (APOT) assay in the samples positive for HPV16 and/or HPV18.

Results

High percentage of HPV (42%) was observed in ovarian carcinoma compared to 8% in the NAT. The high-risk HPV types 16, 18 and 45 were highly associated with the advanced stages of tumor, while low-risk types 6 and 11 were present in NAT. In malignant tissues, HPV-16 was the most predominant genotype followed by HPV-18 and -45. The percentage of viral integration into the host genome was significantly high (61.1%) compared to 38.9% episomal in HPV positive tumors tissues. In HPV18 genotype the percentage of viral integration was 54.5% compared to 45.5% episomal.

Conclusion

The high risk HPV genotypes in ovarian cancer may indicate its role in ovarian carcinogenesis. The HPV vaccination is highly recommended to reduce this type of cancer.

High expression of ezrin predicts poor prognosis in uterine cervical cancer

Background

Ezrin, a member of the ezrin/radixin/moesin (ERM) protein family, plays a pivotal role in tumor invasion and metastasis. This study is aimed to investigate the clinicopathological significance of upregulated ezrin protein expression in uterine cervical cancers.

Methods

Immunohistochemical staining of ezrin protein was performed on uterine cervical cancer specimens from 235 patients. For comparison, 239 cases of cervical intraepithelial neoplasia (CIN), 17 cases of cervical glandular intraepithelial neoplasia (CGIN) and 52 normal cervix samples were also included. qRT-PCR was performed on fresh tissues to detect ezrin mRNA expression levels. HPV infection statuses were genotyped by oligonucleotide microarray, and 10-year survival rates were calculated using the Kaplan-Meier method for 109 cervical cancer patients.

Results

Apical membranous distribution of ezrin protein was only observed in normal cervical glands, while perinuclear staining was only observed in cervical cancers. Strong cytoplasmic and diffuse localization of ezrin were frequently seen in the cervical cancers compared with the normal counterparts. Furthermore, this strongly positive ezrin expression was significantly higher in cervical cancers than in CIN, CGIN, and normal cervical epithelia. Ezrin overexpression was closely related with poor differentiation, late stage, and lymph node metastasis. Additionally, ezrin overexpression was associated with lower 10-year survival rate for patients with early stage cervical cancer, but not for patients with advanced stage.

Conclusions

Aberrant localization and overexpression of ezrin might be an independent effective biomarker for prognostic evaluation of cervical cancers.

Bacteria-human somatic cell lateral gene transfer is enriched in cancer samples

There are 10× more bacterial cells in our bodies from the microbiome than human cells. Viral DNA is known to integrate in the human genome, but the integration of bacterial DNA has not been described. Using publicly available sequence data from the human genome project, the 1000 Genomes Project, and The Cancer Genome Atlas (TCGA), we examined bacterial DNA integration into the human somatic genome. Here we present evidence that bacterial DNA integrates into the human somatic genome through an RNA intermediate, and that such integrations are detected more frequently in (a) tumors than normal samples, (b) RNA than DNA samples, and (c) the mitochondrial genome than the nuclear genome. Hundreds of thousands of paired reads support random integration of Acinetobacter-like DNA in the human mitochondrial genome in acute myeloid leukemia samples. Numerous read pairs across multiple stomach adenocarcinoma samples support specific integration of Pseudomonas-like DNA in the 5′-UTR and 3′-UTR of four proto-oncogenes that are up-regulated in their transcription, consistent with conversion to an oncogene. These data support our hypothesis that bacterial integrations occur in the human somatic genome and may play a role in carcinogenesis. We anticipate that the application of our approach to additional cancer genome projects will lead to the more frequent detection of bacterial DNA integrations in tumors that are in close proximity to the human microbiome.

There are 10× more bacterial cells in the human body than there are human cells that are part of the human microbiome. Many of those bacteria are in constant, intimate contact with human cells. We sought to establish if bacterial cells insert their own DNA into the human genome. Such random mutations could cause disease in the same manner that mutagens like UV rays from the sun or chemicals in cigarettes induce mutations. We detected the integration of bacterial DNA in the human genome more readily in tumors than normal samples. In particular, extensive amounts of DNA with similarity to Acinetobacter DNA were fused to human mitochondrial DNA in acute myeloid leukemia samples. We also identified specific integrations of DNA with similarity to Pseudomonas DNA near the untranslated regulatory regions of four proto-oncogenes. This supports our hypothesis that bacterial integrations occur in the human somatic genome that may potentially play a role in carcinogenesis. Further study in this area may provide new avenues for cancer prevention.