Association of human papillomavirus type 16 integration in the E2 gene with poor disease-free survival from cervical cancer

Genetic Alterations (Amplification and Rearrangement) of D-Type Cyclins Loci in Head and Neck Squamous Cell Carcinoma of Indian Patients

In this study, the alterations (amplification/rearrangement) of 3 D-type cyclins loci were analyzed by Southern blot in 5 dysplastic head and neck lesions and 79 primary head and neck squamous cell carcinoma (HNSCC) of Indian patients to understand the role of the cyclins in development of the disease. No alteration was found in the dysplastic lesions. Overall, 54% of alterations were found in bcl-1/CCND1 locus, whereas amplification was only found in CCND2 and CCND3 loci in 12% and 2% samples, respectively. In bcl-1/CCND1 locus amplification was the major type of alteration; however, rearrangement as well as coalterations had been seen in some samples indicating the common mechanism of activation of this locus in different types of tumors. In bcl-1 region, the breakpoint clustered in the MTC (major translocation cluster) region, whereas in CCND1 the breakpoint located near 3' end of the gene. The coamplification of CCND2 locus with bcl-1, bcl-1/CCND1, and CNND3 loci suggests cumulative effect of these genes in this tumor. The significant association was seen between bcl-1/CCND1 locus alteration with HPV prevalence and poor patient outcome indicating its importance as prognostic marker. This indicates that the genetic instability caused due to HPV infection may induce the alterations in the bcl-1/CCND1 locus, which will provide selective growth advantage to the specific malignant clones resulting poor prognosis of the disease.

Human papillomavirus type 18 variant lineages in United States populations characterized by sequence analysis of LCR-E6, E2, and L1 regions

While HPV 16 variant lineages have been well characterized, the knowledge about HPV 18 variants is limited. In this study, HPV 18 nucleotide variations in the E2 hinge region were characterized by sequence analysis in 47 control and 51 tumor specimens. Fifty of these specimens were randomly selected for sequencing of an LCR-E6 segment and 20 samples representative of LCR-E6 and E2 sequence variants were examined across the L1 region. A total of 2770 nucleotides per HPV 18 variant genome were considered in this study. HPV 18 variant nucleotides were linked among all gene segments analyzed and grouped into three main branches: Asian-American (AA), European (E), and African (Af). These three branches were equally distributed among controls and cases and when stratified by Hispanic and non-Hispanic ethnicities. Among invasive cervical cancer cases, no significant differences in the three HPV variant branches were observed among ethnic groups or when stratified by histopathology (squamous vs. adenocarcinoma). The Af branch showed the greatest nucleotide variability when compared to the HPV 18 reference sequence and was more closely related to HPV 45 than either AA or E branches. Our data also characterize nucleotide and amino acid variations in the L1 capsid gene among HPV 18 variants, which may be relevant to vaccine strategies and subsequent studies of naturally occurring HPV 18 variants. Several novel HPV 18 nucleotide variations were identified in this study.

Antiviral activity of Cidofovir on a naturally human papillomavirus-16 infected squamous cell carcinoma of the head and neck (SCCHN) cell line improves radiation sensitivity

High risk HPV types 16 and 18 are associated with cervical cancer and squamous cell carcinoma of the head and neck (SCCHN). Cidofovir is an antiviral drug used to treat HPV-induced laryngeal papillomatosis and other viral infections, with initial reports suggesting activity in cervical carcinoma cells. We investigated the effects of Cidofovir on a naturally HPV-16-transformed SCCHN cell line (UPCI:SCC090), in comparison with a cervical carcinoma cell line (CasKi) of similar viral characteristics, to evaluate its therapeutic potential. HPV-16 gene transcription was only marginally reduced, and the antiviral and p53 restorative effects were modest in SCC90 cells. However, combination with irradiation enhanced the effects of Cidofovir treatment on these cells. Several days of treatment were required for this effect, which may limit its clinical applicability. Future therapies for HPV-associated tumors may include intralesional antiviral therapy in combination with radiation therapy, but optimization for clinical utility is needed.

Human papillomavirus-16 associated squamous cell carcinoma of the head and neck (SCCHN): A natural disease model provides insights into viral carcinogenesis

Uncertainty regarding the causality of human papillomaviruses (HPVs) in squamous cell carcinoma of the head and neck (SCCHN) necessitates better in vitro models. We carried out molecular analyses of a novel, naturally HPV-16-transformed SCCHN cell line (UPCI:SCC090) and show high copy number of HPV-16 DNA, present in a head to tail, tandemly repeated integrated state. Sequence analysis of the HPV-16 long control region (LCR) in UPCI:SCC090 revealed a deletion of 163 bp, removing a portion of the enhancer sequence, including the binding sites for the transcription factors YY1 and NF1. The E6 and E7 oncogenes of HPV-16 are expressed at high levels in this cell lines, as determined by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). UPCI:SCC090 contains wild-type tumour suppressor TP53 gene, and undetectable p53 protein, except after treatment with cisplatin, specific proteasome inhibitors or by E6 RNA interference, suggesting E6-dependent degradation of p53 in this cell line. The results of our studies are consistent with a causative role of HPV-16 in the pathogenesis of SCCHN.

Human papillomavirus status in advanced cervical cancer: predictive and prognostic significance for curative radiation treatment

Human papillomavirus (HPV) infection plays a major role in oncogenesis of squamous cell carcinoma of the cervix. This study was performed to investigate if HPV status and E2 gene integrity are prognostic parameters for clinical outcome and predictive for radiation response. Forty women with locally advanced cervical cancer treated with curative radiotherapy were analyzed for HPV infection and E2 gene integrity by multiplex polymerase chain reaction. Statistical analyses were performed for overall survival, disease-free survival (DFS), local progression-free survival, and treatment response (clinical complete remission). Twenty-eight (70%) of 40 carcinomas were HPV positive. The only significant factor for a better overall survival, DFS, and local progression-free survival was HPV positivity (P < 0.02, P= 0.02, and P < 0.05, log-rank, respectively). HPV-positive tumors had a significantly better clinical complete remission (67% vs 33%, P= 0.04, Fisher's exact test). An intact E2 gene region showed a trend for a better DFS (P= 0.1, log-rank). This study reveals HPV as an independent prognostic parameter for outcome and radiation response. Integration of the virus genome into host cell DNA might be a molecular target to determine the treatment response of HPV-positive cancers.

The characteristics of human papillomavirus DNA in head and neck cancers and papillomas

AIM

To determine the prevalence, type, physical state, and viral load of human papillomavirus (HPV) DNA in cases of head and neck cancer and recurrent respiratory papillomatosis (RRP).

METHODS

The prevalence and type of HPV DNA was determined in 27 fresh frozen tissue specimens from patients with head and neck cancers and 16 specimens from 10 patients with RRP by MY09/MY11 and GP5+/GP6+ nested polymerase chain reaction (PCR) and subsequent restriction enzyme cleavage. The physical state of HPV DNA was analysed by E1, E2, and E1E2 specific PCRs and Southern blot hybridisation (SBH).

RESULTS

HPV DNA was detected in 13 of 27 cancers and 10 of 10 papillomas. Both low risk HPV-6 and HPV-11 and high risk HPV-16 were present in cancers in low copy numbers, whereas papillomas exclusively harboured low risk HPV-6 and HPV-11. E1E2 PCRs failed to determine the physical state of HPV in cancers except one case where HPV-6 DNA was integrated. In contrast to cancers, all papillomas showed the episomal state of HPV DNA and a relatively higher viral load.

CONCLUSIONS

Based on the prevalence, type, physical state, and copy number of HPV DNA, cancers and papillomas tend to show a different HPV DNA profile. The 100% positivity rate of low risk HPV types confirms the role of HPV-6 and HPV-11 in the aetiology of RRP.

Physical status of HPV-16 in esophageal squamous cell carcinoma

BACKGROUND

Infection with high-risk human papillomavirus (HPV) has been implicated as one of the risk factors of esophageal squamous cell carcinoma (ESCC). Integration of viral DNA into host genome is essential for carcinogenesis since it promotes disruption of the HPV E2 gene, leading to abnormal expression of E6 and E7 oncoproteins.

OBJECTIVES AND STUDY DESIGN

To investigate the viral integration status of HPV-16 infection in ESCC, 35 HPV-positive ESCC specimens collected from Chinese patients were subject to real-time quantitative PCR for determination of physical status of HPV-16 by analyzing the ratios of E2 to E6 genes.

RESULTS

Our results showed that only 8.6% (3/35) of the HPV-16 positive specimens harbored exclusively the episomal form (i.e. E2/E6 ratio > or = 1), whereas the remaining 91.4% contained either only the integrated form (5.7%, with E2/E6 ratio = 0) or a mixture of episomal and integrated forms of viral molecules (85.7%, with E2/E6 ratios > 0 but < 1). Amongst the 30 cancer specimens carrying mixed integrated and episomal forms, 28 had E2/integrated E6 ratios of less than 1, indicating a predominance of integrated form of viral genes in these lesions.

CONCLUSION

Our finding of frequent integration of viral DNA in the host genome suggests that integration HPV-16 is common in ESCC from Chinese patients and implies that HPV infection may play a role in the pathogenesis of ESCC.

E2 sequence variations of HPV 16 among patients with cervical neoplasia seen in the Indian subcontinent

OBJECTIVES

Specific nucleotide variations in the E2 DNA sequence were looked for in samples with an intact human papillomavirus (HPV) 16 episomal E2 DNA.

METHODS

Ninety-two women, 76 with invasive cervical carcinoma and 16 with cervical intraepithelial neoplasia (CIN) were recruited. HPV DNA typing was performed by polymerase chain reaction (PCR) based restriction fragment length polymorphism (RFLP). Intact episomal E2 DNA of HPV 16 was detected by PCR. Important nucleotide variations in samples with amplifiable E2 DNA were detected by RFLP. Nucleotide sequencing was performed on representative samples to confirm RFLP findings.

RESULTS

A total of 89 (96.7%) women were positive for HPV DNA. Of these, 56 (63%) were positive for HPV 16, and of these, 38 (68%) were positive for intact episomal HPV 16 E2 DNA while 18 (32%) were negative. Samples with intact episomal HPV 16 E2 DNA sequences were grouped into four different digestion profiles I to IV based on RFLP patterns. Digestion patterns revealed absence of any sequence variations in samples with digestion profile I and presence of a 2983 A-G variation in those with profile II. Samples with digestion profiles III and IV revealed three variations in the hinge region (3516 C-A, 3538 A-C, 3566 T-G) and two in the DNA binding domain (3684 C-A, 3694 T-A) of the E2 sequence. Sequencing performed on representative samples confirmed RFLP findings.

CONCLUSIONS

PCR-RFLP helped in the identification of important HPV 16 E2 sequence variations, circumventing the need for sequencing. The presence of the nucleotide variations in positions that could alter the biological and immunological functions of the E2 protein combined with its increased occurrence in this study bring out the importance of these variations.

Mapping and analysis of HPV16 integration sites in a head and neck cancer cell line

Human papillomavirus (HPV) is a circular double-stranded DNA virus implicated in at least 90% of cervical and anogenital cancers and has been observed in approximately 20% of squamous cell carcinomas of the head and neck (SCCHN). Transcription of the viral oncogenes E6 and E7 is regulated by expression of the E2 protein. Disruption of the E2 gene sequence due to viral integration results in upregulation of E6 and E7, which promote tumorigenesis by abrogating p53 and pRb functions. HPV integration sites in cervical and anogenital cancers have been mapped primarily to chromosomal fragile sites and in some cases have been shown to integrate within tumor suppressor genes or other cancer-related genes. To study viral integration sites in SCCHN, we examined an HPV16-infected SCCHN cell line cultured from a tongue-base tumor. HPV fluorescence in situ hybridization (FISH) revealed multiple integrated viral DNA copies in blocks throughout the genome. Sequential FISH and spectral karyotyping identified integration sites on chromosomes 3, 6, 9q, 13q and t(1;8)(q;?). Restriction site-polymerase chain reaction (RS-PCR) was performed to identify the viral-cellular junctions. Sequence analyses confirmed integration sites at 9q31.1 and 6p21 and revealed a novel junction at 16p12.3. Subsequent chromosome breakage studies suggested that the observed viral-cellular integration sites may have occurred within common fragile sites. Additional studies using RT-PCR for E6--E7 viral transcripts showed oncoprotein expression from episomal and integrated viral sequences. Our results suggest that viral integration of HPV in SCCHN appears to occur nonrandomly through targeting specific chromosomal sequences prone to breakage.

Flow cytometric quantitation of the protective efficacy of dendritic cell based vaccines in a human papillomavirus type 16 murine challenge model

A murine model for the assessment of protective immunity to human papillomavirus (HPV) type 16, a virus that does not naturally infect mice, is described. In this system, protection was tested following intranasal challenge of mice with a recombinant vaccinia virus expressing both the selected HPV antigen and a beta-galactosidase (beta-gal) reporter. The extent of viral infectivity was determined by measuring beta-gal positive lung cells using flow cytometry. The efficacy of this model to measure protective immunity was evaluated by priming mice with the beta-gal vaccinia virus then challenging the mice with the same virus. Vaccinia primed mice had negligible numbers of beta-gal positive cells in the lung 5 days following viral challenge indicating protection, whereas around 50% of cells were infected in immunologically naive, challenged mice. The protective efficacy of two dendritic cell vaccines for HPV16 was measured in this model. Both vaccines provided some protection to subsequent viral challenge, compared with their controls. Although this protection model was applied to HPV in this study, it may also have broad application to other viruses that do not infect mice naturally.

Physical state and expression of HPV DNA in benign and dysplastic cervical tissue: different levels of viral integration are correlated with lesion grade

OBJECTIVE

Human papillomavirus (HPV) infection is the most important event in the malignant transformation of human cervical epithelium. Several high-risk (HR-)HPV subtypes have been identified, which lead to CIN and subsequently to invasive carcinoma. The reason for this phenomenon is still unknown, but it seems to be related to the physical state of HPV DNA.

METHODS

Digene HC II test was used to identify HR- and/or low-risk (LR-)HPV infections in cervical swabs of 275 women attending our clinic for routine cytological screening and/or colposcopy because of an abnormal Pap smear comprising low-grade squamous intraepithelial lesions (LGSIL) and high-grade SIL (HGSIL). Specific HR (16, 18, 31, 33, 52b, 58) and LR (6, 11) subtypes were characterized in cervical biopsies of 10 women with benign cellular changes and of 68 women with CIN I-III by the PCR-restriction enzyme method. The physical state of HPV DNA (episomal, mixed and integrated form) was analyzed by bi-dimensional (2D)-gel electrophoresis. In addition, mRNA expression of E6/E7 genes was analyzed by RT-PCR. Furthermore, the relative virus load was determined in nine selected cases. The physical state and transcriptional activity of HPV DNA were then correlated to histopathological results.

RESULTS

LR-HPV infection [27 cases (9.8%)] and HR-HPV infection [121 cases (44%)] of cervical swabs were clearly correlated to the degree of SIL. Further HPV typing in cervical biopsies of 78 women showed that HPV6 and 11 were restricted to benign cellular changes, CIN I and II, whereas HPV16 and 18 were observed predominantly in CIN III/CIS (P=0.01). No clear distribution pattern was observed for HPV31, 33, 52b and 58. Expression of HPV E6 and E7 transcripts was uniformly correlated with the different physical state of HPV DNA. Analyzing the physical state of these HPV subtypes, HPV6 and 11 could only be detected as an episomal form, independent of SIL grade. In normal epithelium and in CIN I and II, HPV16 and 18 were exclusively found in the episomal form. In CIN III/CIS, 15 of 30 cases of HPV16 (50%) and 16 of 17 cases of HPV18 (94%) were exclusively integrated into the host genome. Like HPV16/18, HPV31, 33, 52b and 58 were also present in the episomal form in normal epithelium and in CIN I and II, but were integrated in 80% of the CIN III/CIS (4/5) cases.

CONCLUSION

Absent integration of HPV16 DNA in some CIN III/CIS suggests that integration is not always required for progression early dysplastic lesions. In contrast, integration of HPV type 18 and others appears to be of major importance for the transforming efficacy of cervical dysplasia. The applied method represents a sensitive instrument to assess the physical state of HPV and is useful to predict the progression of disease.

The prevalence of the HPV 16 genome, integrated viral status and p53 genotype in cervical cancer population of north-eastern Hungary, the correlation with the established markers of tumour progression

OBJECTIVES

To evaluate the prevalence of the HPV 16 integrated status and the p53 genotype in cervical cancer in north-eastern Hungary and their correlation with the established prognostic factors.

STUDY DESIGN

Parallel with the routine histological examination, Southern blot hybridisation and multiplex PCRs were used to detect type/physical state of HPV DNA in primary tumours and in regional lymph nodes combined with p53 genotyping of 83 patients.

RESULTS

46.9% (39/83) prevalence rate of HPV 16 genome was found. The frequency of viral integration (76.9% in primary tumours and 95.2% in regional lymph nodes) and that of the p53Arg homozygous genotype (64.1%) proved to be higher than reported from other parts of the world. The HPV 16 integration and the p53 genotype, failed to correlate with the FIGO stage and lymphatic spread.

CONCLUSION

The prevalence of the integrated status of the HPV 16 genome combined with homozygous p53Arg genotype is relatively high in Hungary. These factors however failed to show a strong correlation with the established markers of tumour progression.

Organization of human papillomavirus productive cycle during neoplastic progression provides a basis for selection of diagnostic markers

The productive cycle of human papillomaviruses (HPVs) can be divided into discrete phases. Cell proliferation and episomal maintenance in the lower epithelial layers are followed by genome amplification and the expression of capsid proteins. These events, which occur in all productive infections, can be distinguished by using antibodies to viral gene products or to surrogate markers of their expression. Here we have compared precancerous lesions caused by HPV type 16 (HPV16) with lesions caused by HPV types that are not generally associated with human cancer. These include HPV2 and HPV11, which are related to HPV16 (supergroup A), as well as HPV1 and HPV65, which are evolutionarily divergent (supergroups E and B). HPV16-induced low-grade squamous intraepithelial lesions (CIN1) are productive infections which resemble those caused by other HPV types. During progression to cancer, however, the activation of late events is delayed, and the thickness of the proliferative compartment is progressively increased. In many HPV16-induced high-grade squamous intraepithelial lesions (CIN3), late events are restricted to small areas close to the epithelial surface. Such heterogeneity in the organization of the productive cycle was seen only in lesions caused by HPV16 and was not apparent when lesions caused by other HPV types were compared. By contrast, the order in which events in the productive cycle were initiated was invariant and did not depend on the infecting HPV type or the severity of disease. The distribution of viral gene products in the infected cervix depends on the extent to which the virus can complete its productive cycle, which in turn reflects the severity of cervical neoplasia. It appears from our work that the presence of such proteins in cells at the epithelial surface allows the severity of the underlying disease to be predicted and that markers of viral gene expression may improve cervical screening.

Study of viral integration of HPV-16 in young patients with LSIL

AIMS

To investigate the physical status of human papillomavirus 16 (HPV-16) in low grade squamous intraepithelial lesions (LSILs) as a means of determining the percentage of viral integration.

METHODS

Ninety two LSIL/HPV positive Thin Prep(TM) samples were initially tested for the E6 gene by the polymerase chain reaction (PCR) to identify the HPV-16 virus. To avoid false positive results, the specificity of the bands obtained from PCR was confirmed by Southern blot hybridisation with internal oligonucleotide probes. Next, a PCR screen for the E2 gene was performed to identify those samples in which the virus was integrated. Viral integration was detected in just over half of them.

RESULTS

Twenty of the 92 samples were HPV-16 positive, as shown by PCR for the E6 gene. Southern blot analysis confirmed that 13 of these samples were positive for the viral E6 gene. Thus, viral integration was detected in just over a half of the samples positive for HPV-16.

CONCLUSIONS

These data show that HPV-16 integration occurs in a subset of LSILs. The measurement of HPV-16 integration would be a helpful complementary tool for cytological evaluation in primary cervical screening to identify those patients at risk of developing high grade squamous intraepithelial lesions and cervical cancer.

Integrations of the hepatitis B virus (HBV) and human papillomavirus (HPV) into the human telomerase reverse transcriptase (hTERT) gene in liver and cervical cancers

Chronic infections with the hepatitis B virus (HBV) and high-risk human papillomaviruses (HPVs) are important risk factors for hepatocellular carcinoma (HCC) and cervical cancer (CC), respectively. HBV and HPV are DNA viruses that almost invariably integrate into the host genome in invasive tumors. The viral integration sites occur throughout the genome, leading to the presumption that there are no preferred sites of integration. A number of viral integrations have been shown to occur within the vicinity of important cancer-related genes. In studies of HBV-induced HCC and HPV-induced CC, we have identified two HBV and three HPV integrations into the human telomerase reverse transcriptase (hTERT) gene. Detailed characterization of the integrations revealed that four integrations occurred within the hTERT promoter and upstream region and the fifth integration occurred in intron 3 of the hTERT gene. None of the integrations altered the hTERT coding sequence and all resulted in juxtaposition of viral enhancers near hTERT, with potential activation of hTERT expression. Our work supports the hypothesis that the sites of oncogenic viral integration are nonrandom and that genes at the sites of viral integration may play important roles in carcinogenesis.

Common fragile sites are preferential targets for HPV16 integrations in cervical tumors

The development of cervical cancer is highly associated with human papillomavirus (HPV) infection. HPV integration into the genome of infected cervical cells is temporally associated with the acquisition of the malignant phenotype. A relationship between the sites of HPV integration in cervical cancer and the position of the common fragile sites (CFSs) has been observed at both the cytogenetic and molecular levels. To further explore this relationship at the molecular level, we used RS-PCR to rapidly isolate cellular sequences flanking the sites of HPV16 integration in 26 primary cervical tumors. Human bacterial artificial chromosome clones were isolated based on these flanking sequences and used as probes for fluorescence in situ hybridization on aphidicolin-stimulated metaphases. Our data demonstrate that 11/23 HPV16 integrations in cervical tumors occurred within CFSs (P&<0.001). In addition, we show that deletions and complex rearrangements frequently occur in the cellular sequences targeted by the integrations and that integrations cluster in FRA13C (13q22), FRA3B (3p14.2), and FRA17B (17q23). Finally, our data suggest that cellular genes, such as Notch 1, are disrupted by the HPV16 integrations, which may contribute to the malignant phenotype.

Human papillomavirus type 16 status in cervical carcinoma cell DNA assayed by multiplex PCR

Integration of human papillomavirus (HPV) DNA into host genome occurs early in cancer development and is probably an important event in malignant transformation of cervical cancer. The HPV genome integration usually disrupts E2 gene open reading frames. It results in the lack of E2 gene suppressor of the synthesis of E6 and E7 products which, in turn, leads to the overexpression of E6 and E7 genes. The oncogenic HPV types (HPV16, -18, -45, and -58) can be present as episomes or may integrate into human chromosomes. Sixty-six cervical cancer patients positive for HPV16 were tested for the presence of E6, E2, E1, and L1 genes. Multiplex PCR was carried out in all cases. Using cluster analysis, the calculated ratios of E1/E6, E2/E6, L1/E6, E1/E2, and E2/(E1*E6) gene amplification products were divided into two or three statistically different groups. These were used for statistical analysis of the prevalence of specific gene types in histological types of cancer, different levels of clinical staging, and histologically confirmed nodal metastases. The statistical analysis proved a significant correlation in the ratios of E2/E6 and E1/E2 only. The E2/E6 and E1/E2 were higher in carcinoma in situ than in advanced squamous cancers. The E2/E6 ratios were lower in higher clinical stages. The multiplex PCR estimation of the E2/E6 ratio could be a simple method for selecting patients with a high risk of a poor outcome in a standard stage-dependent treatment procedure.

Human papillomavirus DNA in cervical lesions from Morocco and its implications for cancer control

To determine the types of human papillomaviruses (HPV) in northern Morocco, information which is needed for the design and use of HPV vaccines, we have analysed 129 cervical biopsies from this region. In our study, 91 cases were HPV positive, 45 cases had HPV-16 DNA, and 20 cases had HPV-18 DNA. This distribution of virus type was similar in inflammatory cervical lesions and in invasive cervical carcinomas. In conclusion, the HPV type distribution in Morocco is similar to that in other African Mediterranean countries, where the proportion of HPV-18 cases is significantly higher than in Europe. Determination of virus-type distribution is essential for vaccination programs.

HPV DNA detection by in situ hybridization with catalyzed signal amplification on thin-layer cervical smears

Thin layer-based technology in cervical cancer screening now allows both Papanicolaou staining and HPV testing on the same sample. Here, we show that in situ hybridization with catalyzed reporter deposition is a powerful HPV detection method when applied on thin-layer cervical smears, allowing distinction between two staining patterns suggestive of two different physical states of HPV DNA, where diffuse signals are suggestive of episomes and punctate signals are suggestive of viral DNA integration.

HPV16 and HPV18 in genital tumors: Significantly different levels of viral integration and correlation to tumor invasiveness

The integration of the high-risk HPV16 and HPV18 types into the cell genome is considered an important step in malignant transformation. The relationship between the physical status of the virus and clinical/pathological parameters was studied by type-specific and multiplex PCR for E6, E2, and E1 sequences in 86 genital tumors from different sites, consisting of 69 invasive carcinomas (including 5 microinvasive carcinomas), 9 carcinomas in situ, 6 severe dysplasias, and 2 moderate dysplasias. Forty tumors contained HPV16 (46.6%), 7 HPV18 (8.1%), and 39 both viruses (45.3%). HPV16 DNA was found either as pure integrant (35.4%), or pure episome (36.7%), or a mixture of both (27.8%). Conversely, all 46 lesions containing HPV18 showed pure integrated forms. The physical status of both types was not related to the tumor site, the tumor/node/metastasis stage, or the histological differentiation grade of the invasive carcinomas. HPV16 integration was significantly associated with invasiveness. Interestingly, in double infections when HPV16 coexisted with HPV18, its genome was found more frequently in episomal form than in single infections where, conversely, it was mostly integrated (P < 0.0001), suggesting a sort of competition for cell integration sites. The complete HPV18 integration, even in pre-neoplastic lesions, indicates a different behavior in genital transformation compared with HPV16 and may reflect a major aggressiveness of this viral type. In conclusion, virus typing in conjunction with the evaluation of the integration status may provide a better prognostic evaluation together with an improved diagnosis.

Antibodies to human papillomavirus 16 L1 virus-like particles as an independent prognostic marker in cervical cancer

OBJECTIVE

Infection with high-risk human papillomavirus (HPV) types such as HPV-16 is a major risk factor for the development of cervical cancer. HPV-16 capsid antibodies are detectable in approximately 50% of patients with HPV-16 DNA-positive cervical cancer. We investigated the prognostic significance of HPV capsid antibodies for survival in patients with cervical cancer in comparison with conventional clinicopathologic features such as staging, histologic grading, histology, age, and treatment modality.

STUDY DESIGN

Serum samples from 68 patients with cervical cancer and 65 healthy female control subjects were analyzed by enzyme-linked immunosorbent assay for HPV-specific immunoglobulin G (IgG) antibodies to baculovirus expressed HPV-6, HPV-11, HPV-16, and HPV-18 L1 virus-like particles (VLPs).

RESULTS

HPV-16 L1 IgG antibodies were detectable in 6 of 65 (9%) of the control subjects and in 19 of 68 (28%) of the patients with cervical cancer (P =.007). In the subgroup of patients with HPV-16 DNA-positive cervical cancer (comprising 50% of the investigated samples), HPV-16 L1 antibodies were detected in 40%. HPV-16 L1 seropositivity was in univariate and multivariate analysis in addition to International Federation of Gynecology and Obstetrics stage, the only independent positive prognostic factor for overall survival (P =.01).

CONCLUSION

Antibodies to HPV-16 L1 were found to be an independent prognostic factor for overall survival in patients with cervical cancer. Thus, HPV-16 infection may be involved not only in oncogenesis but also in tumor development and behavior.

Evidence of an association between human papillomavirus and impaired chemotherapy-induced apoptosis in cervical cancer cells

OBJECTIVES

The aim of this study was to determine cervical cancer cell sensitivity to chemotherapy-induced apoptosis based on human papillomavirus (HPV) status.

METHODS

CaSki (HPV-positive) and C33A (HPV-negative) cells were treated with camptothecin or cisplatin. Cellular viability was determined by trypan blue exclusion. Apoptotic indexes were determined by flow cytometric analysis of annexin V labeling and morphological changes. Mitochondrial release of cytochrome c was determined by immunofluorescence using confocal microscopy. Caspase 3 activation and bax expression were assessed by immunoblotting.

RESULTS

CaSki cells displayed chemoresistance to both camptothecin and cisplatin. Low response to apoptogenic stimuli was evidenced by a marginal increase in the apoptotic cell fraction after camptothecin treatment (22.9 +/- 2.56%) compared with control (17.8 +/- 1.95%). Cisplatin (14.8 +/- 1.01%) caused a slight decrease in apoptosis. Mitochondrial release of cytochrome c and cleavage of caspase 3 could not be demonstrated in CaSki cells after treatment. Despite p53 mutation, C33A cells were sensitive to the antiproliferative effects of camptothecin and cisplatin. Mean apoptotic events were 17.5 +/- 0.33 for control, 42 +/- 1.76 for cisplatin, and 38.1 +/- 0.75 for camptothecin. An intact cytochrome c pathway was demonstrated in C33A cells leading to cleavage of caspase 3 after camptothecin treatment. The constitutive bax expression demonstrated in both cell lines displayed no change after camptothecin treatment.

CONCLUSION

HPV-positive cervical cancer cells have an inherent resistance to chemotherapy-induced apoptosis. HPV-dependant inactivation of apoptotic regulators such as p53 and blockage of downstream events such as cytochrome c release and caspase 3 activation might be elemental to this cellular survival advantage provided by high-risk oncogenic papillomavirus.

Integrated human papillomavirus type 16 is frequently found in cervical cancer precursors as demonstrated by a novel quantitative real-time PCR technique

In contrast to cervical cancer, integration of human papillomavirus (HPV) DNA into the host genome has been considered a rare event in cancer precursor lesions (cervical intraepithelial neoplasia [CIN]). With our new real-time PCR method, we demonstrated that integrated HPV type 16 (HPV16) is already present in CIN lesions. The physical state of HPV16 and the viral load were simultaneously detected. A unique region of the E2 open reading frame (ORF) that is most often deleted during HPV16 integration is targeted by one set of PCR primers and a probe, and another set targets the E6 ORF. In episomal form, both targets should be equivalent, while in integrated form, the copy numbers of E2 would be less than those of E6. The method was tested with DNAs from 31 cervical lesions (non-CIN to CINIII) from 24 women prospectively followed up for 10 years. This report presents viral load and integration results from the largest series of CIN lesions described to date. Only one sample contained exclusively episomal HPV16 DNA, and this lesion regressed spontaneously. Samples from another patient, with only integrated HPV16, rapidly progressed from CINI to CINIII in 2 years. In all other patients, episomal and integrated forms of HPV16 DNA were found to coexist. Rapid progression of the CIN lesions was closely associated with a heavy load of integrated HPV16. Thus, the method described here is a very sensitive tool with which to assess the physical state of HPV, which is useful in predicting disease progression.

Human papillomaviruses: into the new millennium

Human papillomaviruses (HPV) are newsworthy in this new millennium. Numerous articles have appeared in the lay press ranging in style and quality from informative essays to sensationalized exposes. Women, sensitized by confusing information, are asking obstetricians hard questions about HPV transmission and prevention, partner notification, the need for HPV testing, and methods of treatment. These questions are difficult because none of the answers are clear cut. This article provides the practicing gynecologist and obstetrician a concise and accurate summary of clinically important issues surrounding HPV. Current knowledge about HPV virology, epidemiology, testing, and the prospects for vaccination and other prevention measures is summarized.

Human papillomavirus positive squamous cell carcinoma of the oropharynx: a radiosensitive subgroup of head and neck carcinoma

BACKGROUND

Epidemiologic evidence points to a connection between viral infection by the human papillomavirus (HPV) and a subgroup of squamous cell carcinoma of the oropharynx. To assess the impact of HPV infection on the response of these tumors toward radiotherapy, the authors retrospectively determined the presence of the virus and the integrity of the viral E2 gene in tumors of patients who have undergone curative irradiation.

METHODS

Paraffin embedded biopsies from 99 patients were analyzed for HPV infection and E2 gene integrity by multiplex PCR. The experimental findings were correlated with clinical characteristics, known risk factors, and treatment outcome.

RESULTS

Fourteen of 99 tumors were HPV positive (11 HPV16, 1 HPV33, 1 HPV35, and 1 HPV45). Human papillomavirus positivity was closely linked to female gender (odds ratio [OR], 5.75; P = 0.004), age older than 56 years (OR, 7.42; P = 0.012), nonsmokers (OR, 21.33; P = 0.00001), and alcohol abstainers (OR, 5.35; P = 0.012). There was an inverse association with p53 nuclear immunoreactivity (OR, 0.06; P = 0.008). The Kaplan-Meier survival estimates showed a better local control (P = 0.050, log-rank) and a better overall survival (P = 0.046, log-rank) for patients with HPV positive tumors. In the multivariate analysis, HPV positivity remained to be associated with a lower risk of local failure (risk ratio [RR], 0.31; P = 0.048). Four of 11 HPV16 positive tumors had a disrupted E2 gene. Only tumors with a disrupted E2 gene manifested local treatment failure.

CONCLUSIONS

Human papillomavirus positivity designates a specific subgroup of oropharyngeal squamous cell carcinomas of the oropharynx that arise preferentially among individuals with no consumption of tobacco and alcohol and that have a favorable outcome attributable to an increased sensitivity toward radiotherapy.

Human papillomavirus infection, risk for subsequent development of cervical neoplasia and associated population attributable fraction

BACKGROUND

Human papillomavirus (HPV) is the major cause of cervical neoplasia but estimates of the population attributable fraction (PAR%), of HPV vary. PAR% has not been derived from longitudinal studies although assessment of HPV exposure prior to the neoplasia diagnosis should increase validity of such estimates.

AIMS

Systematic review and meta-analysis of longitudinal studies on HPV associated relative risk (RR) for and PAR% of HPV16 in cervical neoplasia.

METHODS

Pertinent data from longitudinal studies was made available through Medline and substituted by various hand searches. HPV associated weighted mean RR, with 95% confidence interval (CI) of cervical neoplasia, and the PAR% of HPV16 in cervical carcinoma were estimated both for unselected and low HPV prevalence populations.

RESULTS

HPV associated RR of cervical carcinoma in PCR-based studies was 17 (95% CI 8.2-33). HPV16 associated RRs in seroepidemiological studies were 3.3 (95% CI 2.2-4.9) for the unselected population, HPV16 seroprevalence 11.0%, and 12.5 (95% CI 5.5-29) for a population with low HPV16 seroprevalence of 5.3%. Corresponding PAR% estimates of HPV16 were 27 and 44%, respectively.

CONCLUSION

Protective vaccination against HPV16 infection would prevent up to 44% of cervical carcinoma.

Physical status of the E2 human papilloma virus 16 viral gene in cervical preneoplastic and neoplastic lesions

BACKGROUND

Integration of human papilloma virus (HPV) 16 DNA is considered an important genetic change in cervical lesion progression towards ICC. The viral E2 gene is often disrupted by this process, releasing suppression of viral E6/E7 oncogenes, a key factor for oncogenic progression.

OBJECTIVES

To evaluate the physical status of HPV 16 E2 gene in cervical preneoplastic and neoplastic lesions and its relation with lesion severity.

STUDY DESIGN

A sensitive PCR approach for the detection of an intact E2 HPV 16 gene in infected epithelial cells from the cervix with low grade squamous intraepithelial lesion (LGSIL), high grade squamous intraepithelial lesion (HGSIL) and invasive cervical carcinoma (ICC) diagnosis was applied. The correlation between gene disruption and lesion stage was examined.

RESULTS

Sixty-two LGSIL, 39 HGSIL and 24 ICC samples were analyzed. Fifty-seven LGSIL [92%], 13 HGSIL [33%] and 4 ICC [17%] showed results compatible with an intact E2 gene, while 5 LGSIL [8%], 26 HGSIL [67%] and 20 ICC [83%] samples gave no signal.

CONCLUSIONS

HPV 16 E2 gene disruption showed a positive correlation with cervical lesion progression, particularly from LGSIL to HGSIL. Although additional genetic events are very likely to be needed for HGSIL to ICC progression, the E2 gene disruption is a putative early marker to consider in the prognostic analysis of HPV 16 chronically infected women.

Physical state of HPV16 and chromosomal mapping of the integrated form in cervical carcinomas

Using a procedure based on restriction enzyme cleavage, self-ligation, and inverse polymerase chain reaction (rliPCR), the authors investigated 18 cervical intraepithelial neoplasia III (CIN III) cases and 37 invasive squamous carcinomas for integration of human papillomavirus type 16 (HPV16). All eighteen CIN III cases (severe dysplasia or high-grade squamous intraepithelial lesion) were found to harbor episomal HPV, but one of the samples contained mixed episomal and integrated forms. Seventeen of 37 invasive cervical carcinoma samples were identified previously as containing the completely integrated HPV16 genome by using PCR covering the entire E1/E2 gene, and this was confirmed by rliPCR in 16 cases. One case, however, showed a low level of episomal deoxyribonucleic acid in addition to the predominant integrated form. Of the remaining 20 carcinoma samples showing episomal forms in the previous analysis, 14 were found to contain integrated forms using rliPCR, and four contained multimeric episomal forms. Thus, in total, 31 of 37 of the carcinomas (84%) showed the integrated HPV16 genome. The rliPCR product from five carcinoma cases was cloned into a plasmid vector and used as a template for "primer walking" deoxyribonucleic acid sequencing to deduce human sequences flanking the integrated HPV genome. Based on this information, bacterial artificial chromosome (BAC) and P1-derived artificial chromosome (PAC) clones were obtained and used as probes in fluorescent in situ hybridization experiments on human metaphase chromosomes. The results of the fluorescent in situ hybridization experiments showed evidence for HPV16 integration in chromosome regions 1q25, 3q28, 6p25, 11p13, and 18q22. Sixteen carcinoma samples, containing episomal HPV16, were sequenced in the long control region. Evidence for changes in E2 binding or silencer YY1 sequences was found in only two samples.

Variants of the long control region of human papillomavirus type 16

Expression of the human papillomavirus (HPV) E6 and E7 oncogenes is regulated on the transcriptional level by specific protein-binding sites contained in the viral long control region (LCR). Sequence changes within the LCR region may have an impact on the transcription of viral oncogenes, possibly resulting in differences in the oncogenic potential of the virus. The present study was designed to determine the sequence variability of the LCR of HPV 16 and to assess whether certain LCR variants do correlate with the clinical outcome of the disease of the uterine cervix. The entire LCR segment of HPV 16 was analysed from 37 cervical biopsy specimens derived from 28 women included in the Kuopio long-term prospective follow-up study. The LCR sequence was identical with the reference sequence in six HPV 16 isolates. Overall, 14 different HPV 16 LCR variants were identified. One of the variants showed sequence variation typical of the Asian-American variant lineage of HPV 16, and all the other variants appeared to belong to the European variant group. The European variants exhibited low genetic diversity, and only five of these LCR variants contained nucleotide changes involving known or proposed binding sites for transcription factors. The variants with changes at nucleotide positions 7193 and 7521 was the most prevalent, accounting for almost 37% of infections. This variant (7193; 7521) has been previously demonstrated to have similar transcriptional activity compared with the reference isolate by Veress and colleagues J Gen Virol 1999, 80, 1035-1043. The reference isolate, variant (7193; 7521) and variants with changes within transcription factor binding sites accounted for most of the infections, and no significant differences were found in the comparison of the distribution of these different LCR isolates in cases where the disease showed progression to severe cervical intraepithelial neoplasia (CIN) or carcinoma in situ (CIS). Notably, both the reference isolate and variant (7193; 7521) were also closely associated with infections showing more aggressive behaviour. According to the present findings, in European HPV 16 isolates, intratype genetic variation of the LCR region does not seem to be commonly responsible for differences in the pathogenicity of the virus and thereby for a risk of progressive infections.

Nuclear matrix attachment regions of human papillomavirus type 16 repress or activate the E6 promoter, depending on the physical state of the viral DNA

Two nuclear matrix attachment regions (MARs) bracket a 550-bp segment of the long control region (LCR) containing the epithelial cell-specific enhancer and the E6 promoter of human papillomavirus type 16 (HPV-16). One of these MARs is located in the 5' third of the LCR (5'-LCR-MAR); the other lies within the E6 gene (E6-MAR). To study their function, we linked these MARs in various natural or artificial permutations to a chimeric gene consisting of the HPV-16 enhancer-promoter segment and a reporter gene. In transient transfections of HeLa cells, the presence of either of these two MARs strongly represses reporter gene expression. In contrast to this, but similar to the published behavior of cellular MARs, reporter gene expression is stimulated strongly by the E6-MAR and moderately by the 5'-LCR-MAR in stable transfectants of HeLa or C33A cells. To search for binding sites of soluble nuclear proteins which may be responsible for repression during transient transfections, we performed electrophoretic mobility shift assays (EMSAs) of overlapping oligonucleotides that represented all sequences of these two MARs. Both MARs contain multiple sites for two strongly binding proteins and weak binding sites for additional factors. The strongest complex, with at least five binding sites in each MAR, is generated by the CCAAT displacement factor (CDP)/Cut, as judged by biochemical purification, by EMSAs with competing oligonucleotides and with anti-CDP/Cut oligonucleotides, and by mutations. CDP/Cut, a repressor that is down-regulated during differentiation, apparently represses HPV-16 transcription in undifferentiated epithelials cells and in HeLa cells, which are rich in CDP/Cut. In analogy to poorly understood mechanisms acting on cellular MARs, activation after physical linkage to chromosomal DNA may result from competition between the nuclear matrix and CDP/Cut. Our observations show that cis-responsive elements that regulate the HPV-16 E6 promoter are tightly clustered over at least 1.3 kb and occur throughout the E6 gene. HPV-16 MARs are context dependent transcriptional enhancers, and activated expression of HPV-16 oncogenes dependent on chromosomal integration may positively select tumorigenic cells during the multistep etiology of cervical cancer.

Asian-american variants of human papillomavirus type 16 have extensive mutations in the E2 gene and are highly amplified in cervical carcinomas

Human-papillomavirus (HPV)-E2 protein is involved in gene-expression regulation and replication of HPV genome. Disruption of the E2 gene during viral integration has been proposed as a mechanism of tumoral progression, since the expression of E6/E7 viral oncogenes is allowed. However, retention of E1/E2 genes and high viral amplification are frequently found in HPV16-positive carcinomas of some populations. In this study, we investigated whether retention of E1/E2 and viral amplification are associated with particular HPV16 E2 variants in cervical carcinomas. HPV16 detection, E1/E2 integrity and viral amplification were explored by Southern blot in 123 cervical carcinomas. HPV16 variants were identified by Southern blot and by sequencing E6, L1/MY and E2 regions. Of 46 HPV16-positive tumors, 34 were positive for E1/E2 and 14 of them showed a variant restriction pattern by mutations in E2. All 14 were Asian-American (AA) variants and, of 11 sub-classified, 6 were AA-a and 5 AA-c. Two E1/E2-negative tumors also contained the AA-c variant, while the remaining HPV16-positive tumors contained only European variants. The E2 gene of AA variants showed 24 mutations, 19 identical in both sub-classes. The 24 mutations were distributed throughout the entire gene and 19 result in 18 amino-acid changes. The AA variants were associated with E1/E2-positive carcinomas with more than 50 viral copies/cell (p = 0.035). The association of Asian-American E2 variants with retention of E1/E2 suggests that E2 variation may be an alternative mechanism de-regulating the expression of viral oncogenes.

Analysis by multiplex PCR of the physical status of human papillomavirus type 16 DNA in cervical cancers

Integration of human papillomavirus (HPV) DNA occurs early in cancer development and is an important event in malignant transformation of cervical cancer. Integration of HPVs preferentially disrupts or deletes the E2 open reading frame, which results in the loss of its expression. The preferential disruption of the E2 gene causes the absence of the E2 gene sequences in the PCR product following integration. Twenty-two carcinomas positive for HPV type 16 (HPV-16) DNA were first tested for the disruption of the E2 gene by PCR. A specific fragment of the E2 gene was not amplified in 10 cases, suggesting integration of HPV DNA into the host genome. Next, multiplex PCR for the HPV E2 and E6 genes was carried out in the remaining 12 cases. Copy numbers of both genes should be equivalent in episomal forms, while the E2 gene copy number will be smaller than that for E6 following the preferential disruption of the E2 gene in concomitant forms. Although relative ratios of HPV E2 to E6 PCR products (E2/E6 ratios) ranged from 1.40 to 2.34 in 10 of 12 cases, multiplex PCR products from 2 cases displayed extremely low ratios of 0.69 and 0.61. Southern blot hybridization with an HPV-16 probe revealed that only in these two cases was both episomal and integrated HPV DNA being carried simultaneously. Thus, multiplex PCR for the E2 and E6 genes of HPV-16 DNA following PCR for the E2 gene can distinguish the pure episomal form from a mixed form of episomal and integrated HPV DNA. Clinical application of this technique will help researchers to understand the implication of the integration of HPV DNA for cervical carcinogenesis and cervical cancer progression.

The molecular genetics of cervical carcinoma

In the pathogenesis of cervical carcinoma there are three major components, two of them related to the role of human papillomaviruses (HPV). First, the effect of viral E6 and E7 proteins. Second, the integration of viral DNA in chromosomal regions associated with well known tumour phenotypes. Some of these viral integrations occur recurrently at specific chromosomal locations, such as 8q24 and 12q15, both harbouring HPV18 and HPV16. And third, there are other recurrent genetic alterations not linked to HPV. Recurrent losses of heterozygosity (LOH) have been detected in chromosome regions 3p14-22, 4p16, 5p15, 6p21-22, 11q23, 17p13.3 without effect on p53, 18q12-22 and 19q13, all of them suggesting the alteration of putative tumour suppressor genes not yet identified. Recurrent amplification has been mapped to 3q+ arm, with the common region in 3q24-28 in 90% of invasive carcinomas. The mutator phenotype, microsatellite instability, plays a minor role and is detected in only 7% of cervical carcinomas. The development of cervical carcinoma requires the sequential occurrence and selection of several genetic alterations. The identification of the specific genes involved, and their correlation with specific tumour properties and stages could improve the understanding and perhaps the management of cervical carcinoma.

Expression of human papillomavirus 16 E2 protein in Schizosaccharomyces pombe delays the initiation of mitosis

Infection by some types of human papillomavirus (HPV) is associated with the development of cervical cancer. Analysis of viral DNA from cervical tumours shows that the E2 gene is frequently disrupted during integration into the host cell's DNA. It has therefore been suggested that loss of E2p is an important step in malignant transformation. Expression of E2p in the fission yeast Schizosaccharomyces pombe retards the G2-M transition, by delaying activation of Cdc2p kinase. In contrast, S phase progression, and commitment to cell division in late G1 are not affected. The delay is independent of the transcriptional trans-activation function of E2p, and does not result from E2p DNA binding mimicking DNA damage. Increased expression of E2p also delays mitotic initiation in mammalian cells. S. pombe may thus provide a simple model for the analysis of E2p function.

Human papillomavirus (HPV) DNA copy number is dependent on grade of cervical disease and HPV type

The association between human papillomavirus (HPV) DNA copy number and cervical disease was investigated. Viral DNA copy number for the most common high-risk HPV types in cervical cancer (types 16, 18, 31, and 45) was determined in cervical cytobrush specimens from 149 women with high-grade cervical intraepithelial neoplasias (CIN II-CIN III), 176 with low-grade CIN (CIN I), and 270 with normal cytology. Quantitative, PCR-based fluorescent assays for each of the HPV genotypes and for the beta-globin gene were used. The amount of cellular DNA increased significantly with increasing disease; thus, HPV was expressed as copies per microgram of cellular DNA. The assay had a dynamic range of >10(7), allowing documentation for the first time of the wide range of HPV copy numbers seen in clinical specimens. Median HPV DNA copy number varied by more than 10(4) among the viral types. HPV16 was present in the highest copy number; over 55% of HPV16-positive samples contained more than 10(8) copies/microgram. Median copy number for HPV16 showed dramatic increases with increasing epithelial abnormality, an effect not seen with the other HPV types. HPV16 increased from a median of 2.2 x 10(7) in patients with normal cytology, to 4.1 x 10(7) in CIN I patients, to 1.3 x 10(9) copies/microgram in CIN II-III patients. Even when stratified by cervical disease and viral type, the range of viral DNA copies per microgram of cellular DNA was quite large, precluding setting a clinically significant cutoff value for "high" copy numbers predictive of disease. This study suggests that the clinical usefulness of HPV quantitation requires reassessment and is assay dependent.

Human papilloma virus type 16 E6 gene expression in oral exophytic epithelial lesions as detected by in situ rtPCR

OBJECTIVE

We adopted an in situ reverse transcriptase polymerase chain reaction method of detecting and determining the frequency of early (E6) gene expression of human papilloma virus type 16 at the individual cell level in a sample of oral exophytic lesions with various degrees of epithelial hyperplasia and dysplasia in immunosuppressed and immunocompetent patients.

STUDY DESIGN

The significance of differences between the study groups was determined by Mantel-Haenszel chi-square analysis and calculation of odds ratios, accounting for immunosuppression and degree of dysplasia, respectively.

RESULTS

Grouped together, the lesions of dysplasia (mild to severe) and squamous cell carcinoma were found to be 16 times more likely to express human papilloma virus E6 mRNA than the benign lesions (P = .0013); in the lesions of immunosuppressed patients, human papilloma virus 16 E6 was roughly 10 times more likely to be expressed than in those of the immunocompetent patients (P = .0008, accounting for dysplasia).

CONCLUSIONS

Our data indicate that human papilloma virus 16 E6 gene expression, and perhaps integration of the virus in the host genome, might play a role in the development of oral neoplasia in association with immunosuppression.

Recurrent integration of papillomavirus DNA within the human 12q14-15 uterine breakpoint region in genital carcinomas

Genital carcinomas are associated with human papillomaviruses, and the viral DNA is frequently integrated in the host cell genome. Recurrent chromosomal alterations are genetic markers for specific tumor phenotypes. To demonstrate that papillomavirus DNA integration is indeed a recurrent chromosomal aberration, we mapped two independent papillomavirus integration sites in the human 12q14-15 region, one containing HPV16 DNA and the other HPV18 DNA. The two HPV integration sites map approximately 10 kbp from each other within the cosmid LLNL12NCO1-196E1 clone. The integration site corresponding to HPV16 DNA in SK-v cells is proximal to the 5' end of a DNA segment known to be rearranged by integration of HPV18 DNA in another cervical carcinoma cell line, SW756. Both integrations are located in the PAL2 locus within the uterine leiomyoma cluster region of translocation.