Dataset Information

Multiplex Identification of Human Papillomavirus 16 DNA Integration Sites in Cervical Carcinomas.

ABSTRACT: Cervical cancer is caused by high-risk human papillomaviruses (HPV), in more than half of the worldwide cases by HPV16. Viral DNA integration into the host genome is a frequent mutation in cervical carcinogenesis. Because integration occurs into different genomic locations, it creates unique viral-cellular DNA junctions in every single case. This singularity complicates the precise identification of HPV integration sites enormously. We report here the development of a novel multiplex strategy for sequence determination of HPV16 DNA integration sites. It includes DNA fragmentation and adapter tagging, PCR enrichment of the HPV16 early region, Illumina next-generation sequencing, data processing, and validation of candidate integration sites by junction-PCR. This strategy was performed with 51 cervical cancer samples (47 primary tumors and 4 cell lines). Altogether 75 HPV16 integration sites (3'-junctions) were identified and assigned to the individual samples. By comparing the DNA junctions with the presence of viral oncogene fusion transcripts, 44 tumors could be classified into four groups: Tumors with one transcriptionally active HPV16 integrate (n?=?12), tumors with transcribed and silent DNA junctions (n?=?8), tumors carrying episomal HPV16 DNA (n?=?10), and tumors with one to six DNA junctions, but without fusion transcripts (n?=?14). The 3'-breakpoints of integrated HPV16 DNA show a statistically significant (p<0.05) preferential distribution within the early region segment upstream of the major splice acceptor underscoring the importance of deregulated viral oncogene expression for carcinogenesis. Half of the mapped HPV16 integration sites target cellular genes pointing to a direct influence of HPV integration on host genes (insertional mutagenesis). In summary, the multiplex strategy for HPV16 integration site determination worked very efficiently. It will open new avenues for comprehensive mapping of HPV integration sites and for the possible use of HPV integration sites as individualized biomarkers after cancer treatment of patients for the early diagnosis of residual and recurrent disease.

SUBMITTER: Xu B

PROVIDER: S-EPMC3688939 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

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Multiplex Identification of Human Papillomavirus 16 DNA Integration Sites in Cervical Carcinomas.

Xu Bo B Chotewutmontri Sasithorn S Wolf Stephan S Klos Ursula U Schmitz Martina M Dürst Matthias M Schwarz Elisabeth E

PloS one 20130618 6

Cervical cancer is caused by high-risk human papillomaviruses (HPV), in more than half of the worldwide cases by HPV16. Viral DNA integration into the host genome is a frequent mutation in cervical carcinogenesis. Because integration occurs into different genomic locations, it creates unique viral-cellular DNA junctions in every single case. This singularity complicates the precise identification of HPV integration sites enormously. We report here the development of a novel multiplex strategy fo ...[more]

PMID: 23824673

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Project description:BackgroundPersistent infection with oncogenic Human Papillomavirus (HPV) is associated with the development of cervical cancer with each genotype differing in their relative contribution to the prevalence of cervical disease. HPV DNA testing offers improved sensitivity over cytology testing alone but is accompanied by a generally low specificity. Potential molecular markers of cervical disease include type-specific viral load (VL), integration of HPV DNA into the host genome and methylation of the HPV genome. The aim of this study was to evaluate the relationship between HPV type-specific viral load, integration and methylation status and cervical disease stage in samples harboring HPV16, HPV18, HPV31 or HPV45.MethodsSamples singly infected with HPV16 (n=226), HPV18 (n=32), HPV31 (n=75) or HPV45 (n=29) were selected from a cohort of 4,719 women attending cervical screening in England. Viral load and integration status were determined by real-time PCR while 3'L1-URR methylation status was determined by pyrosequencing or sequencing of multiple clones derived from each sample.ResultsViral load could differentiate between normal and abnormal cytology with a sensitivity of 75% and a specificity of 80% (odds ratio [OR] 12.4, 95% CI 6.2-26.1; p<0.001) with some variation between genotypes. Viral integration was poorly associated with cervical disease. Few samples had fully integrated genomes and these could be found throughout the course of disease. Overall, integration status could distinguish between normal and abnormal cytology with a sensitivity of 72% and a specificity of 50% (OR 2.6, 95% CI 1.0-6.8; p=0.054). Methylation levels were able to differentiate normal and low grade cytology from high grade cytology with a sensitivity of 64% and a specificity of 82% (OR 8.2, 95% CI 3.8-18.0; p<0.001). However, methylation varied widely between genotypes with HPV18 and HPV45 exhibiting a broader degree and higher magnitude of methylated CpG sites than HPV16 and HPV31.ConclusionsThis study lends support for HPV viral load and CpG methylation status, but not integration status, to be considered as potential biomarkers of cervical disease.

Project description:It has been reported that >90% of women with cervical cancer are human papillomavirus (HPV)-positive, with HPV16 and 18 being the most 'highest-risk' HPV genotypes. However, in numerous women, HPV infection will not progress to cervical cancer. Accordingly, more appropriate screening markers need to be explored. In the present study, genome-wide DNA methylomic differences between cervical cancer tissues with HPV-16 or HPV-18 infection and normal cervical tissues were detected by using an Illumina Human Methylation 850 K BeadChip. The Gene Ontology functional enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were conducted in order to define the nearest neighbouring genes of differentiated methylation sites. Moreover, differentiated methylation sites were verified using pyrosequencing. KEGG analyses suggested that the focal adhesion pathway and pathways in cancer were highly enriched. Bioinformatics and statistical analysis indicated that the nine CpG loci had the most significant differences amongst the genes involved in these pathways. Among these, six CpG sites in the CHRM2, LAMA4, COL11A1, FGF10, IGF1 and TEK genes were highly associated with HPV-16-positive cervical cancer, as validated using pyrophosphate sequencing. Additionally, 10 significantly different CpG sites of the HPV-18-positive group were selected and verified in The Cancer Genome Atlas, indicating their possible diagnostic roles in cervical cancer development and determination. In addition, eight hypermethylated CpG island sites that were associated with HPV-16-positive cervical cancer tissues and 10 hypermethylated CpG island sites that were associated with HPV-18-positive cervical cancer tissues were identified, highlighting their potential roles in screening and evaluating targeted therapy efficacy and prognosis. The main focus of the present study was to identify the genetic variability in HPV-16- and HPV-18-positive samples and to elucidate possible methylation biomarkers in HPV-positive women with a risk of developing cervical cancer.

Dataset Information

Multiplex Identification of Human Papillomavirus 16 DNA Integration Sites in Cervical Carcinomas.

Publications

Multiplex Identification of Human Papillomavirus 16 DNA Integration Sites in Cervical Carcinomas.

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