Genome-wide profiling of the human papillomavirus DNA integration in cervical intraepithelial neoplasia and normal cervical epithelium by HPV capture technology

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.

The Hallmarks of Cervical Cancer: Molecular Mechanisms Induced by Human Papillomavirus

Human papillomaviruses (HPVs) and, specifically, high-risk HPVs (HR-HPVs) are identified as necessary factors in the development of cancer of the lower genital tract, with CaCU standing out as the most prevalent tumor. This review summarizes ten mechanisms activated by HR-HPVs during cervical carcinogenesis, which are broadly associated with at least seven of the fourteen distinctive physiological capacities of cancer in the newly established model by Hanahan in 2022. These mechanisms involve infection by human papillomavirus, cellular tropism, genetic predisposition to uterine cervical cancer (CaCU), viral load, viral physical state, regulation of epigenetic mechanisms, loss of function of the E2 protein, deregulated expression of E6/E7 oncogenes, regulation of host cell protein function, and acquisition of the mesenchymal phenotype.

Concordance between the BD Onclarity and Roche cobas assays for detection of HPV DNA in a Chinese population

As cervical cancer screening shifts from cytology to human papillomavirus (HPV) testing, a major issue involves validating more HPV tests. In recent years, some HPV tests are used for clinical performance verification in China. The purpose of this study was to explore whether the BD Onclarity (Becton, Dickinson and Company)HPV assay differs from the Roche cobas (Roche Molecular Systems)HPV assay, as determined using 944 cervical samples, including 588 with sequencing results. In the nucleic acid assay accuracy verification, the assays showed excellent concordance for detection of HPV16 (κ = 0.93, 95% confidence interval [CI]: 0.89-0.97) and HPV18 (κ = 0.90, 95% CI: 0.83-0.97), and very good concordance for the 12 other high-risk types (HPV31/33/35/39/45/51/52/56/58/59/66/68, κ = 0.79, 95% CI: 0.75-0.83). The overall agreement for HPV DNA detection between Onclarity and cobas was very good (κ = 0.7755). No difference for ≥CIN2 sensitivity was observed between Onclarity and cobas (both 96.5%), whereas the ≥CIN2 specificity for detection of Onclarity (16.6%, 95% CI: 13.7-19.9) was higher than that of cobas (11.5%, 95% CI: 9.1-14.5). Onclarity exhibited comparable screening performance and triage efficiency compared to cobas in the detection of cervical disease in Chinese women.

Targeted RNA next generation sequencing analysis of cervical smears can predict the presence of hrHPV-induced cervical lesions

BACKGROUND

Because most cervical cancers are caused by high-risk human papillomaviruses (hrHPVs), cervical cancer prevention programs increasingly employ hrHPV testing as a primary test. The high sensitivity of HPV tests is accompanied by low specificity, resulting in high rates of overdiagnosis and overtreatment. Targeted circular probe-based RNA next generation sequencing (ciRNAseq) allows for the quantitative detection of RNAs of interest with high sequencing depth. Here, we examined the potential of ciRNAseq-testing on cervical scrapes to identify hrHPV-positive women at risk of having or developing high-grade cervical intraepithelial neoplasia (CIN).

METHODS

We performed ciRNAseq on 610 cervical scrapes from the Dutch cervical cancer screening program to detect gene expression from 15 hrHPV genotypes and from 429 human genes. Differentially expressed hrHPV- and host genes in scrapes from women with outcome "no CIN" or "CIN2+" were identified and a model was built to distinguish these groups.

RESULTS

Apart from increasing percentages of hrHPV oncogene expression from "no CIN" to high-grade cytology/histology, we identified genes involved in cell cycle regulation, tyrosine kinase signaling pathways, immune suppression, and DNA repair being expressed at significantly higher levels in scrapes with high-grade cytology and histology. Machine learning using random forest on all the expression data resulted in a model that detected 'no CIN' versus CIN2+ in an independent data set with sensitivity and specificity of respectively 85 ± 8% and 72 ± 13%.

CONCLUSIONS

CiRNAseq on exfoliated cells in cervical scrapes measures hrHPV-(onco)gene expression and host gene expression in one single assay and in the process identifies HPV genotype. By combining these data and applying machine learning protocols, the risk of CIN can be calculated. Because ciRNAseq can be performed in high-throughput, making it cost-effective, it can be a promising screening technology to stratify women at risk of CIN2+. Further increasing specificity by model improvement in larger cohorts is warranted.

HPV16 and HPV18 type-specific APOBEC3 and integration profiles in different diagnostic categories of cervical samples

Human papillomavirus (HPV) 16 and 18 are the most predominant types in cervical cancer. Only a small fraction of HPV infections progress to cancer, indicating that additional factors and genomic events contribute to the carcinogenesis, such as minor nucleotide variation caused by APOBEC3 and chromosomal integration. We analysed intra-host minor nucleotide variants (MNVs) and integration in HPV16 and HPV18 positive cervical samples with different morphology. Samples were sequenced using an HPV whole genome sequencing protocol TaME-seq. A total of 80 HPV16 and 51 HPV18 positive samples passed the sequencing depth criteria of 300× reads, showing the following distribution: non-progressive disease (HPV16 n = 21, HPV18 n = 12); cervical intraepithelial neoplasia (CIN) grade 2 (HPV16 n = 27, HPV18 n = 9); CIN3/adenocarcinoma in situ (AIS) (HPV16 n = 27, HPV18 n = 30); cervical cancer (HPV16 n = 5). Similar numbers of MNVs in HPV16 and HPV18 samples were observed for most viral genes, with the exception of HPV18 E4 with higher numbers across clinical categories. APOBEC3 signatures were observed in HPV16 lesions, while similar mutation patterns were not detected for HPV18. The proportion of samples with integration was 13% for HPV16 and 59% for HPV18 positive samples, with a noticeable portion located within or close to cancer-related genes.

Recurrent integration of human papillomavirus genomes at transcriptional regulatory hubs

Oncogenic human papillomavirus (HPV) genomes are often integrated into host chromosomes in HPV-associated cancers. HPV genomes are integrated either as a single copy or as tandem repeats of viral DNA interspersed with, or without, host DNA. Integration occurs frequently in common fragile sites susceptible to tandem repeat formation and the flanking or interspersed host DNA often contains transcriptional enhancer elements. When co-amplified with the viral genome, these enhancers can form super-enhancer-like elements that drive high viral oncogene expression. Here we compiled highly curated datasets of HPV integration sites in cervical (CESC) and head and neck squamous cell carcinoma (HNSCC) cancers, and assessed the number of breakpoints, viral transcriptional activity, and host genome copy number at each insertion site. Tumors frequently contained multiple distinct HPV integration sites but often only one “driver” site that expressed viral RNA. As common fragile sites and active enhancer elements are cell-type-specific, we mapped these regions in cervical cell lines using FANCD2 and Brd4/H3K27ac ChIP-seq, respectively. Large enhancer clusters, or super-enhancers, were also defined using the Brd4/H3K27ac ChIP-seq dataset. HPV integration breakpoints were enriched at both FANCD2-associated fragile sites and enhancer-rich regions, and frequently showed adjacent focal DNA amplification in CESC samples. We identified recurrent integration “hotspots” that were enriched for super-enhancers, some of which function as regulatory hubs for cell-identity genes. We propose that during persistent infection, extrachromosomal HPV minichromosomes associate with these transcriptional epicenters and accidental integration could promote viral oncogene expression and carcinogenesis.

Causes and Consequences of HPV Integration in Head and Neck Squamous Cell Carcinomas: State of the Art

A constantly increasing incidence in high-risk Human Papillomaviruses (HPV)s driven head and neck squamous cell carcinomas (HNSCC)s, especially of oropharyngeal origin, is being observed. During persistent infections, viral DNA integration into the host genome may occur. Studies are examining if the physical status of the virus (episomal vs. integration) affects carcinogenesis and eventually has further-reaching consequences on disease progression and outcome. Here, we review the literature of the most recent five years focusing on the impact of HPV integration in HNSCCs, covering aspects of detection techniques used (from PCR up to NGS approaches), integration loci identified, and associations with genomic and clinical data. The consequences of HPV integration in the human genome, including the methylation status and deregulation of genes involved in cell signaling pathways, immune evasion, and response to therapy, are also summarized.

Short- and long-range cis interactions between integrated HPV genomes and cellular chromatin dysregulate host gene expression in early cervical carcinogenesis

Development of cervical cancer is directly associated with integration of human papillomavirus (HPV) genomes into host chromosomes and subsequent modulation of HPV oncogene expression, which correlates with multi-layered epigenetic changes at the integrated HPV genomes. However, the process of integration itself and dysregulation of host gene expression at sites of integration in our model of HPV16 integrant clone natural selection has remained enigmatic. We now show, using a state-of-the-art 'HPV integrated site capture' (HISC) technique, that integration likely occurs through microhomology-mediated repair (MHMR) mechanisms via either a direct process, resulting in host sequence deletion (in our case, partially homozygously) or via a 'looping' mechanism by which flanking host regions become amplified. Furthermore, using our 'HPV16-specific Region Capture Hi-C' technique, we have determined that chromatin interactions between the integrated virus genome and host chromosomes, both at short- (<500 kbp) and long-range (>500 kbp), appear to drive local host gene dysregulation through the disruption of host:host interactions within (but not exceeding) host structures known as topologically associating domains (TADs). This mechanism of HPV-induced host gene expression modulation indicates that integration of virus genomes near to or within a 'cancer-causing gene' is not essential to influence their expression and that these modifications to genome interactions could have a major role in selection of HPV integrants at the early stage of cervical neoplastic progression.

Evaluation of Integrated HPV DNA as Individualized Biomarkers for the Detection of Recurrent CIN2/3 during Post-Treatment Surveillance

Simple Summary

HPV-DNA integration into the host genome is a frequent step in cervical carcinogenesis and is considered to be a tumor-driving event. Viral integration sites are unique for each patient and could thus serve as highly specific molecular markers for the detection of recurrent disease. Unexpectedly, our study showed that integration sites as individualized biomarkers could not detect all recurrent pre-cancers (CIN2/3). Nevertheless, this is the first study which has identified and validated integration sites in a large number of CIN3 (n = 445) and as such has unraveled several novel findings: The integration frequency observed in CIN3 was much lower than anticipated (10.8% in CIN3 vs. 80% in cervical cancer). Moreover, in contrast to the monoclonal situation in cervical carcinoma, integrated HPV-DNA in CIN3 is most likely confined to clonally expanding subpopulations.

Abstract

Purpose: Post-treatment follow-up in women with cervical pre-cancers (CIN3) is mandatory due to relapse in up to 10% of patients. Standard follow-up based on hrHPV-DNA/cytology co-testing has high sensitivity but limited specificity. The aim of our prospective, multicenter, observational study was to test the hypothesis that an individualized viral-cellular-junction test (vcj-PCR) combined with cytology has a lower false positive rate for the prediction of recurrence compared to standard co-testing. Methods: Pre-surgical cervical swabs served for the identification of HPV16/18 DNA integration sites by next-generation-sequencing (NGS). Samples taken at 6, 12 and 24 months post-surgery were evaluated by cytology, hrHPV-DNA and the patients’ individual HPV-integration sites (vcj-PCR on the basis of NGS). Results: Integration sites were detected in 48 of 445 patients (10.8%), 39 of them had valid follow-up data. The false positive rate was 18.2% (95% CI 8.6–34.4%) for standard hrHPV/cytology at six months compared to 12.1% (95% CI 4.8–27.3%) for vcj-PCR/cytology, respectively (McNemar p = 0.50). Six patients developed recurrences (1 CIN2, 5 CIN3) during follow-up. Standard co-testing detected all, whereas vcj-PCR/cytology detected only five patients with recurrences. Data of 269 patients without evidence of HPV16/18 integration were subject to post-hoc analyses. Standard co-testing revealed a false positive rate of 15.7% (95% CI 11.7–20.7%) and predicted ten of fourteen recurrences at six months. Conclusions: Although highly specific on its own vcj-PCR could not detect all recurrent CIN2/3. Possible reasons for this unexpected result may be multifocal lesions, intratumoral heterogeneity with respect to HPV integration and/or incident CIN.

MicroRNA-Based Fingerprinting of Cervical Lesions and Cancer

The regulatory functions of microRNA (miRNA) are involved in all processes contributing to carcinogenesis and response to viral infections. Cervical cancer in most cases is caused by the persistence of high-risk human papillomavirus (HR-HPV) infection. While oncogenic human papillomaviruses induce aberrant expression of many cellular miRNAs, this dysregulation could be harnessed as a marker in early diagnosis of HR-HPV infection, cervical squamous intraepithelial lesions, and cancer. In recent years, growing data indicate that miRNAs show specific patterns at various stages of cervical pathology. The aim of this review is to systematize current reports on miRNA capacity that can be utilized in personalized diagnostics of cervical precancerous and cancerous lesions. The analysis of the resources available in online databases (National Center for Biotechnology Information—NCBI, PubMed, ScienceDirect, Scopus) was performed. To date, no standardized diagnostic algorithm using the miRNA pattern in cervical pathology has been defined. However, the high sensitivity and specificity of the reported assays gives hope for the development of non-invasive diagnostic tests that take into account the heterogeneity of tumor-related changes. Due to this variability resulting in difficult to predict clinical outcomes, precise molecular tools are needed to improve the diagnostic and therapeutic process.

Genomic landscape analyses in cervical carcinoma and consequences for treatment

Where we are on the road to 'tailor-made' precision medicine for drug-resistant cervical carcinoma? We explored studies about analyses of viral and human genomes, epigenomes and transcriptomes, DNA mutation analyses, their importance in detecting HPV sequences, mechanisms of drug resistance to established and targeted therapies with small molecule or therapeutic antibodies, to radiosensitivity and to chemoradiotherapy. The value of repurposing of old drugs initially approved for other disease indications and now considered for cervix cancer therapy is also discussed. The microbiome influences drug response and survival too. HPV genomic integration sites were less significant. Nomograms (Lee et al., 2013) even outperformed FIGO staging regarding prediction of five-year overall survival times. We conclude that there are still many loose threads to be followed up, before coherent conclusions for individualized therapy of drug-resistant cervical carcinoma can be drawn.

Cervical cancer risk profiling: molecular biomarkers predicting the outcome of hrHPV infection

INTRODUCTION

Cervical cancer affects half a million women worldwide annually. Given the association between high-risk human papillomavirus (hrHPV) infection and carcinogenesis, hrHPV DNA testing became an essential diagnostic tool. However, hrHPV alone does not cause the disease, and, most importantly, many cervical lesions regress to normal in a year because of the host immune system. Hence, the low specificity of hrHPV DNA tests and their inability to predict the outcome of infections have triggered a further search for biomarkers.

AREAS COVERED

We evaluated the latest viral and cellular biomarkers validated for clinical use as primary screening or triage for cervical cancer and assessed their promise for prevention as well as potential use in the future. The literature search focused on effective biomarkers for different stages of the disease, aiming to determine their significance in predicting the outcome of hrHPV infections.

EXPERT OPINION

Biomarkers such as p16/Ki-67, hrHPV genotyping, hrHPV transcriptional status, and methylation patterns have demonstrated promising results. Their eventual implementation in the screening programs may support the prompt diagnosis of hrHPV infection and its progression to cancer. These biomarkers will help in making clinical management decisions on time, thus, saving the lives of hrHPV-infected women, particularly in developing countries.

Genomic, transcriptomic, and viral integration profiles associated with recurrent/metastatic progression in high-risk human papillomavirus cervical carcinomas

Acquisition of recurrent/metastatic potential by a tumor cell defines a critical step in malignant progression. However, understanding of metastatic progression at the molecular level is scarce for cervical carcinomas (CES). In this study, we performed genomic, transcriptomic, and viral profiling of five pairs of primary (CES‐P) and matched recurrent/metastatic tumors (CES‐R/M) with high risk human papillomavirus. Whole exome sequencing revealed mutation features of CES‐R/M including elevated mutation burdens and prevalent copy number alterations compared to their matched CES‐P. A relative deficit of APOBEC‐related mutation signatures accompanying the transcriptional downregulation of APOBEC3A was observed for CES‐R/M. Mutations in genes encoding epigenetic regulators were commonly observed as CES‐R/M‐specific alterations. Immunoprofiling and gene set analysis revealed CES‐Ps were enriched with transcripts representing activated anticancer immunity such as interferon‐gamma pathway, while CES‐R/M exhibited upregulation of genes involved in epithelial‐mesenchymal transition and angiogenesis. Viral capture sequencing revealed that integration sites remained enriched in viral E1 protein domain during malignant progression. Moreover, we found transcriptional upregulation of POSTN and downregulation of APOBEC3A were associated with unfavorable clinical outcomes in CES. Comprehensive genomic and transcriptomic profiling of a rare cohort including CES‐R/M identified metastases‐specific features to advance the molecular understanding into CES metastatic progression with potential clinical implications.

The D2 and D3 Sublineages of Human Papilloma Virus 16-Positive Cervical Cancer in Guatemala Differ in Integration Rate and Age of Diagnosis

Human papillomavirus (HPV) 16 displays substantial sequence variation; four HPV16 lineages (A, B, C, and D) have been described as well as multiple sublineages. To identify molecular events associated with HPV16 carcinogenesis, we evaluated viral variation, the integration of HPV16, and somatic mutation in 96 cervical cancer samples from Guatemala. A total of 65% (62/96) of the samples had integrated HPV16 sequences and integration was associated with an earlier age of diagnosis and premenopausal disease. HPV16 integration sites were broadly distributed in the genome, but in one tumor, HPV16 integrated into the promoter of the IFN regulatory factor 4 (IRF4) gene, which plays an important role in the regulation of the IFN response to viral infection. The HPV16 D2 and D3 sublineages were found in 23% and 30% of the tumors, respectively, and were significantly associated with adenocarcinoma. D2-positive tumors had a higher rate of integration, earlier age of diagnosis, and a lower rate of somatic mutation, whereas D3-positive tumors were less likely to integrate, had later age of diagnosis, and exhibited a higher rate of somatic mutation. In conclusion, Guatemalan cervical tumors have a high frequency of very high-risk HPV16 D2 and D3 sublineages harboring distinct histology, which may help guide future therapeutic strategies to target the tumor and reduce recurrence. SIGNIFICANCE: This study details the biological and molecular properties of the most pathogenic forms of HPV16, the cause of the majority of cervical cancers.

Integration rates of human papilloma virus genome in a molecular survey on cervical specimens among Iranian patients

The human papilloma virus (HPV) as a major causative agent of different cancers is under investigation globally. In this study, we aim to investigate HPV infection in different cytological and pathological stages by different molecular methods, and then the viral genome integration of HPV-16 and -18 is determined by a specific real-time PCR method. The study included women who underwent liquid-based cytology. HPV PCR was conducted by MY09/11 universal primers, HPV genotyping was performed by INNO-LiPA HPV genotyping assay, and the viral genome status was defined by two real-time PCR assays. The statistics were calculated by SPSS v.22 software. In 1668 women included in the study with mean age±std. deviation of 35.6±0.7, HPV was detected in 632 (38%) participants. Following genotyping analyses, 16 HPV types and 713 strains were detected. HPV-16 and HPV-18 from high-risk types and HPV-6 and HPV-11 from low-risk types were the dominant types. We found HPV-16 strains in mixed form (58.8%), and of the HPV-18 strains, the episomal form was prevalent (92.9%). The statistics revealed significant presence of HPV-6 and within normal limits cases; HPV-16 and atypical squamous cells of undetermined significance; HPV-33 as well as HPV-39 and low-grade squamous intraepithelial lesion; HPV-6 and atypical squamous cells of undetermined significance; and HPV-35 as well as HPV-56 and squamous cell carcinoma. Our study showed high prevalence of HPV in low-grade cervical lesions, although it is associated with higher grades. The HPV molecular testing extra to cytology is recommended. HPV-16 and HPV-18 have different programs in genome integration in infected cells.

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.

Insertional oncogenesis by HPV70 revealed by multiple genomic analyses in a clinically HPV-negative cervical cancer

Cervical carcinogenesis, the second leading cause of cancer death in women worldwide, is caused by multiple types of human papillomaviruses (HPVs). To investigate a possible role for HPV in a cervical carcinoma that was HPV-negative by PCR testing, we performed HPV DNA hybridization capture plus massively parallel sequencing. This detected a subgenomic, URR-E6-E7-E1 segment of HPV70 DNA, a type not generally associated with cervical cancer, inserted in an intron of the B-cell lymphoma/leukemia 11B (BCL11B) gene in the human genome. Long range DNA sequencing confirmed the virus and flanking BCL11B DNA structures including both insertion junctions. Global transcriptomic analysis detected multiple, alternatively spliced, HPV70-BCL11B, fusion transcripts with fused open reading frames. The insertion and fusion transcripts were present in an intraepithelial precursor phase of tumorigenesis. These results suggest oncogenicity of HPV70, identify novel BCL11B variants with potential oncogenic implications, and underscore the advantages of thorough genomic analyses to elucidate insights into HPV-associated tumorigenesis.

Risk stratification of cervical lesions using capture sequencing and machine learning method based on HPV and human integrated genomic profiles

From initial human papillomavirus (HPV) infection and precursor stages, the development of cervical cancer takes decades. High-sensitivity HPV DNA testing is currently recommended as primary screening method for cervical cancer, whereas better triage methodologies are encouraged to provide accurate risk management for HPV-positive women. Given that virus-driven genomic variation accumulates during cervical carcinogenesis, we designed a 39 Mb custom capture panel targeting 17 HPV types and 522 mutant genes related to cervical cancer. Using capture-based next-generation sequencing, HPV integration status, somatic mutation and copy number variation were analyzed on 34 paired samples, including 10 cases of HPV infection (HPV+), 10 cases of cervical intraepithelial neoplasia (CIN) grade and 14 cases of CIN2+ (CIN2: n = 1; CIN2-3: n = 3; CIN3: n = 9; squamous cell carcinoma: n = 1). Finally, the machine learning algorithm (Random Forest) was applied to build the risk stratification model for cervical precursor lesions based on CIN2+ enriched biomarkers. Generally, HPV integration events (11 in HPV+, 25 in CIN1 and 56 in CIN2+), non-synonymous mutations (2 in CIN1, 12 in CIN2+) and copy number variations (19.1 in HPV+, 29.4 in CIN1 and 127 in CIN2+) increased from HPV+ to CIN2+. Interestingly, ‘common’ deletion of mitochondrial chromosome was significantly observed in CIN2+ (P = 0.009). Together, CIN2+ enriched biomarkers, classified as HPV information, mutation, amplification, deletion and mitochondrial change, successfully predicted CIN2+ with average accuracy probability score of 0.814, and amplification and deletion ranked as the most important features. Our custom capture sequencing combined with machine learning method effectively stratified the risk of cervical lesions and provided valuable integrated triage strategies.

Universal human papillomavirus typing by whole genome sequencing following target enrichment: evaluation of assay reproducibility and limit of detection

BACKGROUND

We recently described a method for unbiased detection of all known human papillomaviruses (HPV) types with the potential for the determination of their variant and integration from the resulting whole genome sequence data. Considering the complex workflow for target-enriched next generation sequencing (NGS), we focused on the reproducibility and limit of detection (LOD) of this new universal HPV typing assay in this study.

RESULTS

We evaluated the reproducibility and LOD for HPV genotyping based on our recently published method that used RNA-baits targeting whole genomes of 191 HPV types, Agilent SureSelect protocol for target enrichment and Illumina HiSeq 2500 for sequencing (eWGS, enriched whole genome sequencing). Two libraries, prepared from pooled plasmids representing 9 vaccine HPV types at varying input (1-625 copies/reaction), were sequenced twice giving four replicates for evaluating reproducibility and LOD. eWGS showed high correlation in the number of reads mapped to HPV reference genomes between the two flow-cell lanes within (R² = 1) and between experiments (R² = 0.99). The number of mapped reads was positively correlated to copy number (β = 13.9, p < 0.0001). The limit of blank (LOB) could be calculated based on mapped reads to HPV types not included in each sample. HPV genotyping was reproducible for all 9 types at 625 copies using multiple cut-off criteria but LOD was 25 copies based on number of reads above LOB even when multiple types were present. eWGS showed no bias for HPV genotyping under single or multiple infection (p = 0.16-0.99).

CONCLUSIONS

The universal eWGS method for HPV genotyping has sensitivity, competitive with widely used consensus PCR methods with reduced type competition, and with the potential for determination of variant and integration status. The protocol used in this study, using defined samples varying in complexity and copy number, analyzed in replicate and duplicate assays, is applicable to most WGS methods.

Genome-wide profiling of human papillomavirus DNA integration in liquid-based cytology specimens from a Gabonese female population using HPV capture technology

Human papillomavirus (HPV) is recognised as the cause of precancerous and cancerous cervical lesions. Furthermore, in high-grade lesions, HPV is frequently integrated in the host cell genome and associated with the partial or complete loss of the E1 and E2 genes, which regulate the activity of viral oncoproteins E6 and E7. In this study, using a double-capture system followed by high-throughput sequencing, we determined the HPV integration status present in liquid-based cervical smears in an urban Gabonese population. The main inclusion criteria were based on cytological grade and the detection of the HPV16 genotype using molecular assays. The rate of HPV integration in the host genome varied with cytological grade: 85.7% (6/7), 71.4% (5/7), 66.7% (2/3) 60% (3/5) and 30.8% (4/13) for carcinomas, HSIL, ASCH, LSIL and ASCUS, respectively. For high cytological grades (carcinomas and HSIL), genotypes HPV16 and 18 represented 92.9% of the samples (13/14). The integrated form of HPV16 genotype was mainly found in high-grade lesions in 71.4% of samples regardless of cytological grade. Minority genotypes (HPV33, 51, 58 and 59) were found in LSIL samples, except HPV59, which was identified in one HSIL sample. Among all the HPV genotypes identified after double capture, 10 genotypes (HPV30, 35, 39, 44, 45, 53, 56, 59, 74 and 82) were detected only in episomal form. Our study revealed that the degree of HPV integration varies with cervical cytological grade. The integration event might be a potential clinical prognostic biomarker for the prediction of the progression of neoplastic lesions.

TaME-seq: An efficient sequencing approach for characterisation of HPV genomic variability and chromosomal integration

HPV genomic variability and chromosomal integration are important in the HPV-induced carcinogenic process. To uncover these genomic events in an HPV infection, we have developed an innovative and cost-effective sequencing approach named TaME-seq (tagmentation-assisted multiplex PCR enrichment sequencing). TaME-seq combines tagmentation and multiplex PCR enrichment for simultaneous analysis of HPV variation and chromosomal integration, and it can also be adapted to other viruses. For method validation, cell lines (n = 4), plasmids (n = 3), and HPV16, 18, 31, 33 and 45 positive clinical samples (n = 21) were analysed. Our results showed deep HPV genome-wide sequencing coverage. Chromosomal integration breakpoints and large deletions were identified in HPV positive cell lines and in one clinical sample. HPV genomic variability was observed in all samples allowing identification of low frequency variants. In contrast to other approaches, TaME-seq proved to be highly efficient in HPV target enrichment, leading to reduced sequencing costs. Comprehensive studies on HPV intra-host variability generated during a persistent infection will improve our understanding of viral carcinogenesis. Efficient identification of both HPV variability and integration sites will be important for the study of HPV evolution and adaptability and may be an important tool for use in cervical cancer diagnostics.

Comprehensive genomic variation profiling of cervical intraepithelial neoplasia and cervical cancer identifies potential targets for cervical cancer early warning

Background

To better understand the pathogenesis of cervical cancer (CC), we systematically analysed the genomic variation and human papillomavirus (HPV) integration profiles of cervical intraepithelial neoplasia (CIN) and CC.

Methods

We performed whole-genome sequencing or whole-exome sequencing of 102 tumour-normal pairs and human papillomavirus probe capture sequencing of 45 CCs, 44 CIN samples and 25 normal cervical samples, and constructed strict integrated workflow of genomic analysis.

Results

Mutational analysis identified eight significantly mutated genes in CC including four genes (FAT1, MLL3, MLL2 and FADD), which have not previously been reported in CC. Targetable alterations were identified in 55.9% of patients. In addition, HPV integration breakpoints occurred in 97.8% of the CC samples, 70.5% of the CIN samples and 42.8% of the normal cervical samples with HPV infection. Integrations of high-risk HPV strains in CCs, including HPV16, 18, 33 and 58, also occurred in the CIN samples. Moreover, gene mutations were detected in 52% of the CIN specimens, and 54.8% of these mutations occurred in genes that also mutated in CCs.

Conclusion

Our results lay the foundation for a deep understanding of the molecular mechanisms and finding new diagnostic and therapeutic targets of CC.

Molecular characterization and integrative genomic analysis of a panel of newly established penile cancer cell lines

Cell line models are essential tools to study the molecular mechanisms underlying tumor initiation and progression. There are limited treatment options for penile squamous cell carcinoma (PSCC), accounting for 1–2% of male tumors in developing countries, and limited progress in preclinical research in PSCC due to lacking available models with identified genomic characteristics. Here, biological and molecular characteristics and whole-genomic alterations were analyzed in a panel of PSCC cell lines newly established in our laboratory. These cell lines were all human papillomavirus (HPV)-negative, epithelial-like, immortalized, and tumorigenic in nude mice, whereas they displayed different proliferation, migration and invasion capacities in vitro, and tumorigenic ability in nude mice. They were all cisplatin sensitive, anti-EGFR therapy resistant, and androgen irresponsive. Whole-genomic sequecing analysis revealed that transition mutations (C:G>T:A and T:A>C:G) were the most common substitution types in these cell lines, whereas ERCC5, TP53, PTH1, CLTCL1, NOTCH2, MAP2K3, CDK11A/B, USP6, ADCH5, BCLAF1, CDKN2A, FANCD2, HRAS, and NOTCH1 were the most frequently altered genes. Amplifications of MYC, PLAG1, NCOA2, RUNX1T1, COX6C, and EGFR and losses of FBXW7, TET2, XPC, and FANCE were frequently observed in cell lines. The exomic variations between cell lines and their corresponding cancer tissues were highly consistent. Genetic variations were mainly involved in the MAPK, Jak-STAT, TGF-beta, Notch, and apoptosis signaling pathways. Conclusively, these panel of PSCC cell lines established in our laboratory harbor some common or specific biological characteristics and genomic variations, and they may serve as optimal models to investigate the molecular mechanisms underlying the progression, metastasis, relapses, and treatment resistance of PSCC and to develop effective treatment strategy.

Prevalence of human papillomavirus genotypes and relative risk of cervical cancer in China: a systematic review and meta-analysis

High-risk HPV (hrHPV) is related to cervical carcinogenesis, although clinical data comparing the natural history and carcinogenic potential of type-specific HPV remain limited. Furthermore, the nationwide prevalence rates of overall and type-specific HPV among women with cervical precancerous lesions and cancer have not been reported. Here, a meta-analysis was performed for type-specific HPV distribution among 30,165 HPV-positive women, including 12,094 invasive cervical cancers (ICCs), 10,026 cervical intraepithelial neoplasia grade 2/3 (CIN2/3), 3246 CIN1, and 4799 normal cervices from 45 PCR-based studies. We found that HPV16 was the most common hrHPV type involved in cervical disease. The HPV16 positivity rate varied little across normal (22.7%) and CIN1 individuals (23.6%) but increased through the CIN2 (37.6%) and CIN3 patients (51.9%) to 65.6% in ICC cases. HPV16, 18, 35, 39, 45, and 59 were more frequent in ICC than CIN3, with ICC:CIN3 ratios ranging from 2.3 for HPV18 to 1.1 for HPV35/45. HPV31, 33, 52, and 58 were more frequent in CIN3 compared with normal cervices but less common in ICC compared with CIN3 (ICC:CIN3 ratios ranging from 0.6 for HPV58 and 0.4 for HPV52). The ICC:normal ratios were particularly high for HPV18, 52 and 58 in West China (4.1, 3.9 and 2.9, respectively) and for HPV45 and 59 in North China (1.6 and 1.1, respectively). In summary, this study is the most comprehensive analysis of type-specific HPV distribution in cervical carcinogenesis and could be valuable for HPV-based cervical cancer screening strategies and vaccination policies in China.

Genomic characterization of human papillomavirus-positive and -negative human squamous cell cancer cell lines

Human cancer cell lines are the most frequently used preclinical models in the study of cancer biology and the development of therapeutics. Although anatomically diverse, human papillomavirus (HPV)-driven cancers have a common etiology and similar mutations that overlap with but are distinct from those found in HPV-negative cancers. Building on prior studies that have characterized subsets of head and neck squamous cell carcinoma (HNSCC) and cervical squamous cell carcinoma (CESC) cell lines separately, we performed genomic, viral gene expression, and viral integration analyses on 74 cell lines that include all readily-available HPV-positive (9 HNSCC, 8 CESC) and CESC (8 HPV-positive, 2 HPV-negative) cell lines and 55 HPV-negative HNSCC cell lines. We used over 700 human tumors for comparison. Mutation patterns in the cell lines were similar to those of human tumors. We confirmed HPV viral protein and mRNA expression in the HPV-positive cell lines. We found HPV types in three CESC cell lines that are distinct from those previously reported. We found that cell lines and tumors had similar patterns of viral gene expression; there were few sites of recurrent HPV integration. As seen in tumors, HPV integration did appear to alter host gene expression in cell lines. The HPV-positive cell lines had higher levels of p16 and lower levels of Rb protein expression than did the HPV-negative lines. Although the number of HPV-positive cell lines is limited, our results suggest that these cell lines represent suitable models for studying HNSCC and CESC, both of which are common and lethal.

Whole-Genome Analysis of Human Papillomavirus Types 16, 18, and 58 Isolated from Cervical Precancer and Cancer Samples in Chinese Women

Human papillomavirus (HPV) types 16, 18 and 58 are ranked the top three high-risk HPV types for cervical intraepithelial neoplasia (CIN) and invasive carcinoma. We aimed to evaluate the diversity of HPV16, HPV18, and HPV58 genetic variants by HPV capture technology combined with next generation sequencing. 295, 73, and 148 variations were observed in 51 HPV16, 7 HPV18, and 11 HPV58 genomes, respectively. HPV16 isolates were predominantly of the A variant lineage, and sublineage A4 (Asian) was the most common. However, there were no significant differences in the distribution of HPV16 A1-3 and A4 variants between CIN1-, CIN2/3, and cervical cancer groups. The 7 HPV18 genomes were assigned to the A3/A4 and A1 sublineages. Of the 11 HPV58 genomes, the most predominant variant sublineages were A2, followed by A1 and B2. The majority of HPV16/18 samples containing contiguous genomic deletions were found to harbor HPV integration. Some T-cell epitope sequences in HPV16 E6 and E7 showed considerable divergence from the prototype NC_001526, suggesting their importance in immunotherapy of HPV-associated carcinomas. In conclusion, sequence diversity and phylogenies of HPV16, 18, and 58 provide the basis for future studies of discrete viral evolution, epidemiology, pathogenicity, and the differences in response to vaccines.