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Combined oral carcinogenicity of HPV-16 and benzo(a)pyrene: an in vitro multistep carcinogenesis model.

We previously immortalized normal human oral keratinocytes by transfection with recombinant HPV-16 DNA and subsequently exposed the cells to benzo(a)pyrene for 7 days. The exposure to benzo(a)pyrene modified the immortalized cells: the modified cells (HOK-16B-BaP) proliferated in an ordinary culture medium containing physiological calcium level (1.5 mM), but demonstrated only enhanced proliferation capacity without tumor formation in nude mice and failed to show in vitro anchorage-independency. In this study, we further modified the HOK-16B-BaP cells by subculturing the cells in a medium containing benzo(a)pyrene for 6 months. The cells were further modified with a chronic benzo(a)pyrene exposure and were termed HOK-16B-BaP-T cells (1) demonstrated a malignant phenotype in organotypic 'raft' culture, (2) showed in vitro anchorage-independency, (3) developed tumors in nude mice when injected subcutaneously, (4) contained a significantly higher copy number of intact and integrated HPV-16 DNA; (5) contained higher level of HPV-16 E6/E7 messages and E7 protein, (6) were more resistant to transforming growth factor-beta 1 and (7) secreted higher level of vascular endothelial growth factor with molecular weight of 56 kd than parental HOK-16B-BaP cells. However, the levels of p53 and ras proteins and the levels of p53, c-myc and c-fos transcripts in the HOK-16B-BaP-T cells were not different from those in the HOK-16B-BaP cells. The highly conserved coding regions of the p53, c-Ha-ras1, and c-Ki-ras2 genes of the tumor cells were not mutated. These data indicate that the HPV-immortalized human oral keratinocytes can convert to tumorigenic cells by chronic exposure to benzo(a)pyrene. The tumorigenic conversion seems to be associated with (1) the overexpression of viral oncogenes such as E6 and E7 genes, (2) the higher resistance of cells to transforming growth factor-beta 1 and (3) the high secretion of 56 kd vascular endothelial growth factor from the cells.

Animals↗

New markers for cervical dysplasia to visualise the genomic chaos created by aberrant oncogenic papillomavirus infections.

Extensive research over the past 20 years provided strong evidence that persistent infections with high risk type human papillomaviruses (HR-HPVs) cause cervical cancer. However, depending on their age, more than 20% of normal women are infected with these viruses and only very few develop clinically relevant dysplastic lesions or even cancer. During an acute HPV infection, expression of viral genes, in particular the viral E6 and E7 oncogenes is restricted to differentiated epithelial cells, which lost the capability to replicate their genomes and are therefore at no further risk for acquiring functionally relevant mutations upon genotoxic damage. High grade cervical dysplasia, however, is initiated by deregulated expression of viral oncogenes in replicating epithelial stem cells. Here, the E6-E7 gene products submerge control of the cell cycle and mitotic spindle pole formation through complex interactions with various cellular protein complexes and induce severe chromosomal instability. The detailed molecular analysis of these interactions allowed to define new biomarkers for dysplastic cervical cells. E7 for example induces increasing expression of the cyclin dependent kinase inhibitor p16(ink4a) in dysplastic cells. This can be used to identify dysplastic cells in histological slides, cytological smears or samples taken for biochemical analyses with an yet unmet fidelity. Detection of specific viral mRNAs derived from integrated HPV genomes in advanced precancers can be used to identify lesions with a particularly high risk for progression into invasive carcinomas (APOT assay). These new markers will result in a modified classification of cervical precancers and improved screening assays. Here, we review the basic concept and potential clinical applications of these new developments.

Biomarkers, Tumor↗

Analysis of molecular alterations in chromosome 8 associated with the development of uterine cervical carcinoma of Indian patients.

OBJECTIVES: We have been done the detailed deletion mapping of chromosome (chr.) 8p21.3-23 to localize the candidate tumor suppressor gene(s) (TSGs) loci as well as studied the mechanism of activation of c-myc gene, located at chr.8q24.1, by analyzing the amplification/rearrangement/HPV integration within approximately 580 kb of c-myc locus in uterine cervical carcinoma (CaCx) of Indian patients. The association between the deletions in chr.8p21.3-23 and alterations in the c-myc locus has also been analyzed. METHODS: The deletion mapping of chr.8p21.3-23 was done by 15 microsatellite markers and the alterations in the c-myc locus were analyzed by Southern hybridization using the pal-1/c-myc/mlvi-4/HPV 16/18 probes in seven cervical intraepithelial neoplasia (CIN) and 55 primary uterine cervical carcinoma. The alterations in chr.8p/q have been correlated with the different clinicopathological parameters. RESULTS: Three discrete minimal deleted regions with high frequencies of loss of heterozygosity (LOH) (37-43%) were identified in the chr.8p23.1-23.2 (D1), 8p23.1 (D2), and 8p 21.3-22 (D3) regions within 0.41-4.62 Mb. The deletion in the D1 region was significantly associated with the deletion in the D2 region (P = 0.03), whereas the deletion in D2 was marginally associated with the deletion in the D3 region (P = 0.07). The alterations in the c-myc locus were seen in 43% of the samples. About 35% of the samples showed coalterations in both arms of chr.8. No significant association was observed with the alterations in chr.8p/q as well as with the different clinicopathological parameters. CONCLUSIONS: The deletions in chr.8p21.3-23 and the alterations in the c-myc locus are independently associated with the development of CaCx. The D1-D3 regions in chr.8p21.3-23 could harbor candidate TSGs associated with the development of this tumor. The c-myc gene was activated by amplification/rearrangement at the pal-1/c-myc/mlvi-4 loci as well as HPV integration in the pal-1 locus in this tumor.

Adult↗

PCR-RFLP studies on chromosome 3p in formaldehyde-fixed, paraffin-embedded cervical cancer tissues.

Loss of heterozygosity (LOH) has been extensively studied on the short arm of chromosome 3, and functional proofs have been obtained defining a tumor-suppressor locus at 3p21-22. We examined 31 paraffin-embedded cervical cancer samples for LOH, using 5 PCR-primer pairs, located around 3p21. Allele loss was found in 19 out of the 27 informative samples (70%) while 13 out of 23 informative samples (56%) had LOH located at 3p21-22. More of the human papillomavirus (HPV)-positive samples had LOH compared to the HPV-negative samples, giving only a weak association between loss of allele and HPV integration. Modifications of the DNA in the formaldehyde-fixed samples were detected, and further studies will be required to clarify how such artifacts may affect restriction fragment length polymorphism (RFLP) studies on fixed tissues.

Alleles↗

Human papillomavirus in head and neck cancer: molecular biology and clinicopathological correlations.

Human papillomaviruses are known to cause cancers of the cervix and other anogenital tract sites. Epidemiologic and molecular pathology studies have also suggested that HPV infection may be associated with cancers of the head and neck. Modes of transmission of HPV infection in the head and neck region have not been fully resolved; however, perinatal transmission and an association between sexual behavior and risk for HPV-positive cancers have been presented. Among the HPV types infecting the mucosa, high-risk, intermediate-risk and low-risk genotypes are defined, depending on their presence in carcinoma or precursor lesions. The phylogenic groups of HPVs also showed a definite correlation with the morphology of head and neck tumors. The groups A6, A7, and A9 include viruses that are frequently demonstrated in basaloid and verrucosus squamous cell carcinomas known to associate with HPV infection. Integration of HPV DNA into the host cell genome occurs early in cancer development and is an important event in malignant transformation. There is a trend for patients with HPV-positive tumors to be nondrinkers or light drinkers, the majority of these patients are females, and the median age is lower than in the case of HPV-negative tumors, but this latter difference was not always statistically significant. In the Kaplan-Meier survival model, the HPV-positive verrucous and basaloid squamous cell carcinomas showed better survival rates than the HPV-negative typical squamous cell carcinomas. An increased radiocurability of HPV-positive head and neck squamous cell carcinoma (HNSCC) has also been demonstrated.

Animals↗

Selective suppression of human papilloma virus type 18 mRNA level in HeLa cells by interferon.

We have studied the effect of IFN on the transcription of integrated HPV 18 DNA in HeLa cells. We found that the amount of cytoplasmic HPV 18 mRNA was markedly reduced in HeLa cells treated with 10(3) IU/ml of IFN alpha or gamma, and that the inhibitory effect was dose dependent and was detectable by 12h after the addition of IFN. Furthermore, northern blot analysis indicated that IFN remarkably reduced 3.4 kb mRNA species of HPV 18 transcripts in HeLa cells. In contrast, the level of beta-actin mRNA was found to increase in IFN treated cells. The results suggest that IFN alpha and gamma selectively inhibited HPV 18 gene expression at the level of transcription.

Cell Cycle↗

Genomic imbalances in 70 snap-frozen cervical squamous intraepithelial lesions: associations with lesion grade, state of the HPV16 E2 gene and clinical outcome.

Host genomic abnormalities may determine the natural history of cervical squamous intraepithelial lesions (SILs). We undertook comparative genomic hybridisation analysis of epithelium carefully microdissected from 70 cervical SILs, the largest series to date. In contrast to previous studies, we used frozen sections for optimal DNA quality and examined whether patterns of DNA copy number imbalance (CNI) are characteristic of SIL grade, human papillomavirus (HPV) status and postoperative recurrence. We identified more CNIs in cervical SIL than previously described, with more CNIs per case in high-grade squamous intraepithelial lesion (HG-SIL) than in low-grade squamous intraepithelial lesion (LG-SIL) (P=0.04). While some CNIs were seen at similar frequencies in HG-SIL and LG-SIL, others, including gain on 1q, 3q and 16q, were found frequently in HG-SIL but not in LG-SIL. There were significantly more CNIs per case in HG-SILs showing loss of the HPV16 E2 gene (a repressor of viral oncogene transcription) (P=0.026) and in HG-SILs that subsequently recurred (P=0.04). Our data are consistent with sequential acquisition of CNIs in cervical SIL progression. Higher frequency of CNI in association with E2 gene loss supports in vitro evidence that high-risk HPV integration is associated with genomic instability. Further investigation of the clinical value of specific host genomic abnormalities in cervical SIL is warranted.

DNA-Binding Proteins↗

Altered expression of Erg and Ets-2 transcription factors is associated with genetic changes at 21q22.2-22.3 in immortal and cervical carcinoma cell lines.

Human Papillomavirus (HPV) type 16 is the most frequently detected HPV in cervical cancer. Although epidemiologic and experimental evidence indicates a prominent role for HPV infection in the development of this disease, other factors are also involved. Altered expression of the ets family transcription factors erg and ets-2 was found associated with the development of cervical carcinoma. Overexpression also occurred in a HPV-16-immortalized cervical cell line, CX16-2, which has HPV integrated at a translocation breakpoint t(19;21) involving 21q22.2-22.3, where these genes have been mapped. Six of 10 cervical carcinoma cell lines overexpressed ets-2 RNA suggesting an association of overexpression with cervical cell neoplasia. A clonally related pair of cervical carcinoma cell lines, C-4I and C-4II, showed differential expression of erg and ets-2. C-4I overexpressed ets-2 RNA compared to normal cervical cells and C-4II. C-4II expressed a 5.3 kb erg transcript not seen in C-4I, ectocervical cells or other cervical carcinoma cell lines examined. Pulsed field gel electrophoresis was used to analyse changes in DNA fragments related to structural changes and to construct a physical map encompassing erg and ets-2. Alterations in erg and ets-2 RNA expression in each of three different cell lines examined were associated with translocations. Association between altered expression of erg and ets-2 and altered regional structural suggests that these genes are important targets in cervical carcinogenesis.

Blotting, Northern↗

[DNA-cytometry in dysplasias of the uterine cervix].

The diagnostic group of dysplasias has been described as "a group of diagnostic impotence". DNA-aneuploidy detected by image cytometry of Feulgen stained pap smears indicates a potentially progressive lesion, representing a high-grade lesion. DNA-cytometry can identify cases of dysplasias which are likely to progress: DNA-aneuploid dysplasias are HSIL. DNA-aneuploidy is the expression of an integral HPV infection. CIN-lesions with episomal HPV infections are DNA-diploid. With the newly developed laserscanning cytometer (LSC) of ThinPrep-Preparation an automatisation of ploidy measurement is possible in combination with HPV-PCR. We recommend DNA-Image-cytometry as a routine method for classification of uterine cervical borderline lesion into regressive and progressive.

Aneuploidy↗

Paired genomic profiling of primary tumor and lymph-node metastases identifies candidate prognostic features in penile squamous cell carcinoma.

BACKGROUND: Penile squamous cell carcinoma (PSCC) is a rare malignancy with limited genomic data in Asian populations. Lymph node metastasis heavily dictates prognosis, yet molecular determinants of progression remain poorly understood. We aimed to characterize the genomic landscape and explore candidate prognostic genomic features using paired primary and metastatic PSCC tumors. PATIENTS AND METHODS: Targeted next-generation sequencing (437 cancer-related genes) was performed on primary tumors and matched lymph node metastases from 20 Chinese patients. Somatic alterations, intralesional heterogeneity, and tumor mutation burden (TMB) were analyzed and correlated with disease-free survival (DFS) and overall survival (OS). RESULTS: The most frequent primary tumor mutations included TP53 (45%) and TERT (40%). Notably, CCND1/FGF19 co-amplification (20% of cases) was associated with inferior DFS (P = .027) and showed a trend toward shorter OS (P = .050). Conversely, T-cell receptor (TCR) pathway alterations correlated with markedly improved survival. Comparing paired lesions revealed 59.8% shared alterations. Elevated TMB in metastases relative to matched primary tumors was significantly associated with poorer DFS (P = .008), while higher intralesional heterogeneity showed a trend toward worse OS. CONCLUSION: Paired profiling revealed broadly conserved genomic features together with lesion-specific divergence in PSCC. Recurrent CCND1/FGF19-containing 11q13 amplification, TCR pathway alterations, and elevated metastatic TMB warrant evaluation as potential prognostic features in larger, independently validated cohorts with integrated HPV and immune profiling.

Humans↗

Chromosomal imbalances in four new uterine cervix carcinoma derived cell lines.

BACKGROUND: Uterine cervix carcinoma is the second most common female malignancy worldwide and a major health problem in Mexico, representing the primary cause of death among the Mexican female population. High risk human papillomavirus (HPV) infection is considered to be the most important risk factor for the development of this tumor and cervical carcinoma derived cell lines are very useful models for the study of viral carcinogenesis. Comparative Genomic Hybridization (CGH) experiments have detected a specific pattern of chromosomal imbalances during cervical cancer progression, indicating chromosomal regions that might contain genes that are important for cervical transformation. METHODS: We performed HPV detection and CGH analysis in order to initiate the genomic characterization of four recently established cervical carcinoma derived cell lines from Mexican patients. RESULTS: All the cell lines were HPV18 positive. The most prevalent imbalances in the cell lines were gains in chromosomes 1q23-q32, 3q11.2-q13.1, 3q22-q26.1, 5p15.1-p11.2, this alteration present as a high copy number amplification in three of the cell lines, 7p15-p13, 7q21, 7q31, 11q21, and 12q12, and losses in 2q35-qter, 4p16, 6q26-qter, 9q34 and 19q13.2-qter. CONCLUSIONS: Analysis of our present findings and previously reported data suggest that gains at 1q31-q32 and 7p13-p14, as well as losses at 6q26-q27 are alterations that might be unique for HPV18 positive cases. These chromosomal regions, as well as regions with high copy number amplifications, coincide with known fragile sites and known HPV integration sites. The general pattern of chromosomal imbalances detected in the cells resembled that found in invasive cervical tumors, suggesting that the cells represent good models for the study of cervical carcinoma.

Chromosome Aberrations↗

Factors predicting persistence of high-risk human papillomavirus (HPV) infections in women prospectively followed-up in three New Independent States (NIS) of the former Soviet Union.

BACKGROUND: We completed an analysis of the factors predicting the persistence of high risk (HR) HPV infections in women participating in a multicenter screening trial in three NIS countries. METHODS: The 543 baseline HR HPV-positive women included in this analysis are derived from a sub-cohort of 887 women who were prospectively followed-up for a mean of 21.6 months (range: 0.5-42.9) as a part of a multi-center screening study in three NIS countries (the NIS cohort study; n = 3,187 women). Of these 543 women, 273 showed persistent HR-HPV in serial Hybrid Capture II (HCII) testing during the follow-up (Group 1), whereas 270 women cleared their infection (Group 2). These two groups were compared with their epidemiological, clinical, and virological data (HCII, PCR) to disclose the factors predicting persistent HR-HPV infection. RESULTS: Women with persistent HR-HPV infections were significantly younger (27.3 yrs) than those who cleared their infection (29.1 yrs) (p = 0.006), and their follow-up time was shorter; 14.1 and 21 months, respectively (p = 0.0001). Both variables were treated as confounders in the multivariate analyses. Of the 66 recorded epidemiological variables, only being a current smoker proved to be an independent predictor (OR 1.693; 95% CI 1.114-2.573; p=0.014). Baseline colposcopy, biopsy or Pap smear did not predict HPV persistence, whereas an incident or persistent abnormal Pap during the follow-up were independent predictors in a multivariate model (p = 0.005), together with the high viral load (HCII RLU/CO at 100 pg/ml cut-off), and HR HPV positive PCR test (p = 0.0001). When all significant variables were entered in the regression model, only the follow-up time (OR 0.950, 95% CI 0.924-0.976; p = 0.0001) and HR-HPV positive PCR (OR 4.169, 95% CI 1.741-9.987; p = 0.001), remained independent predictors. CONCLUSIONS: While several factors were related to HR-HPV persistence in univariate analysis and when adjusted for age and follow-up time as confounders, the only independent predictors in the multivariate regression model were follow-up time and HR-HPV positive PCR. Clearly more data are needed on type-specific persistence and HPV integration as its predictors.

Adult↗

Detection of human papillomavirus (HPV) DNA in laryngeal papilloma.

Laryngeal papillomas are troublesome benign tumors of the larynx. According to their biological behavior, there are two types of laryngeal papillomas--the juvenile and adult types. Two samples of adult-type and five samples of juvenile-type laryngeal papilloma specimens were studied using the Southern blot technique with radioactively labeled human papillomavirus (HPV) 6b, 16, 18 deoxyribonucleic acid (DNA) as probes. We found that there was a linear form, an episomal form, and a concatemer or catenane of HPV DNA in the 5 samples of juvenile laryngeal papilloma and there was no evidence of HPV DNA integration. The HPV DNA in tumor cells is very closely associated with HPV 6b, but has no positive hybridization with HPV 16 and 18 DNA even in a low stringent condition. There was no positive hybridization found in the 2 samples of adult-type laryngeal papilloma with any of the three probes.

DNA Probes, HPV↗

Genomic integration of oncogenic HPV and gain of the human telomerase gene TERC at 3q26 are strongly associated events in the progression of uterine cervical dysplasia to invasive cancer.

Recently proposed events associated with the progression of cervical intraepithelial neoplasia (CIN) 2/3 to cervical carcinoma include integration of human papillomavirus (HPV) into the host genome, genomic instability, and an increase in chromosome 3q copy number. In particular, the gene coding for the RNA component of telomerase (TERC) at 3q26 has been implicated as a possible candidate gene. Since it is not known to date how these events are temporally related during cervical carcinogenesis, the aim of the present study was to assess the correlation between TERC gene copy number and the physical status of HPV during progression in cervical neoplasia. Solitary precursor lesions of the uterine cervix (CIN 2/3, n = 17), lesions associated with a micro-invasive carcinoma (CIN 3&mCA, n = 13), and advanced invasive carcinomas (invCA, n = 7) were analysed by fluorescence in situ hybridization (FISH) to determine the physical status of the virus and TERC gene copy number. The TERC gene was increasingly gained with progression of CIN 2/3 (3 of 17) through CIN 3&mCA (7 of 13) to invCA (5 of 7). In the lesions exhibiting gain of TERC, the virus was predominantly integrated. This was seen in eight of ten diploid lesions, indicating that these events can occur prior to aneuploidization and are strongly associated with the progression of CIN 3 to mCA and invCA (p < 0.001). With progression to carcinoma, a number of these lesions show polyploidization, resulting in aneuploidy and high TERC gene copy numbers. In conclusion, genomic integration of oncogenic HPV and gain of the human telomerase gene TERC appear to be important associated genetic events in the progression of uterine cervical dysplasia to invasive cancer.

Cell Transformation, Neoplastic↗

Systematic review of genomic integration sites of human papillomavirus genomes in epithelial dysplasia and invasive cancer of the female lower genital tract.

Cancers of the anogenital tract as well as some head and neck cancers are caused by persistent infections with high-risk type human papillomaviruses (HPVs). Two viral oncogenes, E6 and E7, induce severe chromosomal instability associated with centrosome aberrations, anaphase bridges, chromosome lagging, and breaking. This occurs early in preneoplastic lesions, when the viral genome still persists in an episomal state. In most invasive cancers and also in a few high-grade dysplastic lesions, however, integration of high-risk HPV genomes into the host genome is observed. Integration seems to be a direct consequence of chromosomal instability and an important molecular event in the progression of preneoplastic lesions. Disruption or deregulation of defined critical cellular gene functions by insertional mutagenesis by integrated HPV genome fragments has been hypothesized as one major promoting factor in the pathogenesis of HPV-associated cancers. This hypothesis was based on the detection of HPV integration events in the area of tumor-relevant genes in few cases. Here, we reviewed >190 reported integration loci with respect to changes in the viral structure and the targeted genomic locus. This analysis confirms that HPV integration sites are randomly distributed over the whole genome with a clear predilection for genomic fragile sites. No evidence for targeted disruption or functional alteration of critical cellular genes by the integrated viral sequences could be found.

Cell Transformation, Viral↗

The prognostic significance of HPV-16 genome status of the lymph nodes, the integration status and p53 genotype in HPV-16 positive cervical cancer: a long term follow up.

OBJECTIVE: Prognostic evaluation of HPV-16 genome status of the pelvic lymph nodes, the integration status of HPV-16 and p53 codon 72 polymorphism in cervical cancer. DESIGN: Prospective cohort study. SETTING: Department of Gynaecological Oncology, University of Debrecen, Hungary. SAMPLE: Thirty-nine patients with HPV-16 positive cervical cancer. METHODS: Primary tumour specimens of 39 cervical cancer patients with HPV-16 positive primary tumour were subjected to multiplex polymerase chain reaction using HPV-16 E1/E2, E7 and p53 codon 72 allele-specific primers. Pelvic lymph nodes of the same patients were also tested for the presence of HPV-16 DNA and for its integration status using HPV-16 E7 and E1/E2 ORF specific primers, respectively. MAIN OUTCOME MEASURES: Progression-free survival. RESULTS: Metastatic lymph nodes carried HPV-16 DNA more frequently than nodes with no evidence of disease (100.0% vs 35.7%, P = 0.001). Cases with HPV-16 positive nodes had higher recurrence rate than those with HPV-16 negative nodes (42.9% vs 11.1%, P = 0.009). There was no difference between cases with and without histologically proven nodal disease with regard to integration status of HPV-16 DNA in the primary tumour (integrated 90.9% vs 71.4%, episomal 9.1% vs 21.4%, mixed 0% vs 7.1%) and p53 codon 72 polymorphism (Arg/Arg 54.5% vs 67.9%, Pro/Pro 0 vs 7.1%, Arg/Pro 45.5% vs 21.4%). CONCLUSIONS: Regardless of the presence of nodal metastasis, HPV-16 status of the nodes is a significant predictor of recurrent disease. HPV-16 integration status and p53 codon 72 genotype do not seem to have a bearing on disease outcome in cervical cancer with HPV-16 positive primary.

Adult↗

Characterization of viral-cellular fusion transcripts in a large series of HPV16 and 18 positive anogenital lesions.

Persistent high risk type human papillomavirus (HR-HPVs) infections induce dysplasia or cancer of the anogenital tract, most notably of the uterine cervix. The viral genome usually persists and replicates as an episomal molecule in early dysplasia, whereas in advanced dysplasia or cervical cancer HPV genomes are frequently integrated into the chromosomal DNA of the host cell. Previous studies suggested that modification of critical cellular sequences by integration of HPV genomes might significantly contribute to the neoplastic transformation of anogenital epithelia (insertional mutagenesis). This prompted us to characterize the integration loci of high risk HPV genomes in a large set of genital lesions. We amplified E6/E7 oncogene transcripts derived from integrated HPV16 and HPV18 genomes and characterized in detail the co-transcribed cellular sequences of 64 primary genital lesions and five cervical cancer cell lines. Database analyses of the cellular parts of these fusion transcripts revealed 51 different integration loci, including 26 transcribed genes (14 known genes, 12 EST sequences with unknown gene function). Seventeen sequences showed similarity to repetitive elements, and 26 sequences did not show any database match other than genomic sequence. Chromosomal integration loci were distributed over almost all human chromosomes. Although we found HPV sequences integrated into cancer related genes and close to fragile sites, no preferential site or integration motif could be identified. These data demonstrate that target directed insertional mutagenesis might occur in few HPV-induced anogenital lesions, however, it is rather the exception than the rule.

Chromosome Mapping↗

Complex genomic rearrangement within the 12q15 multiple aberration region induced by integrated human papillomavirus 18 in a cervical carcinoma cell line.

Human papillomavirus (HPV) DNA is integrated into the host genome in cervical cancer. The cervical carcinoma cell line SW756 has integrated HPV-18 DNA in chromosome region 12q15, in the papillomavirus-associated locus-2 (PAL2). By polymerase chain reaction and hybridization of an arrayed cosmid library with oligonucleotides from the rearranged allele, we determined the pre-integration germline structure of the region. PAL2 was located approximately 10 kb from sequence-tagged site marker U27131, which was the marker most proximal to the 3' flank of the integrated viral DNA. HPV-18 DNA integration induced a complex genomic rearrangement resulting in inversion and deletion of cellular sequences. PAL2 is within the multiple aberration region, which has been shown to be affected in several types of benign tumors of mesenchymal origin. The integrated viral DNA was located 50 kb from a CpG island and 150 kb upstream of the high-mobility group I-C (HMGI-C) gene. The HMGI-C gene and the integrated HPV-18 DNA had opposite transcriptional orientations. No overexpression or altered message of the HMGI-C gene was detected in three cervical carcinoma cell lines. The integrated viral DNA did not affect any other known gene in the region and may be a marker for an unknown gene associated with malignant tumor phenotypes.

Base Sequence↗