Human papillomavirus type 16 is episomal and a high viral load may be correlated to better prognosis in tonsillar cancer

The aim of our study was to investigate the physical state and the viral load of HPV-16 in tonsillar cancer and to correlate these findings with clinical outcome. To distinguish between integrated and episomal forms of HPV, 22 fresh-frozen tonsillar cancer samples were analysed by a method based on restriction enzyme cleavage, ligation and PCR (rliPCR). HPV-16 was detected in 11/22 and HPV-33 in 1/22 of the cancers, hence 12/22 (55%) of the tumours were HPV positive. Only extrachromosomal forms of HPV-16 were observed. Full-length episomal HPV was detected exclusively in 7/11 of the cancers, whereas both full-length and deleted forms of episomal HPV-16 were found in parallel in 2 other tumours. In 1 tumour only a deleted episomal form of HPV-16 was present. In the remaining HPV-16 positive tumour both full-length episomal as well as an 11 kbp PCR product were detected and if the 11 kbp product contained integrated HPV, or was off-size linearised episomal could not be determined. In 2 cervical cancer controls, HPV-16 was integrated and could be chromosome located. HPV-16 was quantified by real-time PCR and most tonsillar cancers contained between 10 to a few hundred copies of HPV per beta-actin. The 6 patients with tumour sections with > or =190 HPV-16 copies/beta-actin remained tumour free (p = 0.026) and had a better survival rate (p = 0.039) when compared to the 5 patients with tumours sections with < or =60 HPV-16 copies/beta-actin. In conclusion, HPV-16 is mainly episomal in tonsillar cancer. The viral load showed a wide distribution and the clinical outcome in our study was better when the HPV load was higher.     

Recurrent integration of human papillomaviruses 16, 45, and 67 near translocation breakpoints in new cervical cancer cell lines.

Progressive chromosomal changes and integration of human papillomavirus (HPV) sequences mark the development of invasive cervical cancer. Chromosomal localization of HPV integration is essential to the study of genomic regions involved in HPV-induced pathogenesis. Yet, the available information about HPV integration loci is still limited, especially with respect to different HPV types. We have established cell lines from five cervical cancers with HPV-16, HPV-45, and HPV-67. We have determined HPV integration sites and karyotype abnormalities by using the multicolor combined binary ratio-fluorescence in situ hybridization method (Tanke et al.) with 24 chromosome-specific paints in combination with full-length HPV DNA probes. All cell lines were cytogenetically abnormal, and exhibited numerical and structural chromosomal deviations. HPV sequences were integrated at various (segments of) chromosomes. Duplicate integration sites were seen in all multiploid cell lines, suggesting that viral integration had preceded chromosomal endoreduplication. HPV-16 was found near the t(3p14.1-14.3;14) breakpoint in cervical squamous cell carcinoma (CSCC)-7 and mainly in episomal form in CSCC-1. HPV-45 was integrated near 3q26-29 in cervical (adeno or adenosquamous) carcinoma (CC)-8 and near 1q21-23 as well as near the t(1q21;22q13) breakpoint in CC-10A and CC-10B variant lines. HPV-67 was localized near the breakpoint of t(3p23-26;13q22-31) in CC-11. Southern blot analysis showed that, except for CSCC-1, the physical state of HPV in the cell lines was the same as in the original tumor lesions. This set of six cervical cancer cell lines included three lines with HPV-45, a major non-Western high-risk HPV type, the first reported HPV-67-positive cell line, and two cell lines with integrated and episomal HPV-16 DNA, respectively. The novel combined binary ratio-fluorescence in situ hybridization technique enabled us to simultaneously map chromosomal rearrangements and HPV integration sites, thereby revealing recurrent integration near translocation junctions for all of these HPV types in the cell lines from three of the five primary tumors. The detection of multiple HPV integration sites at rearranged chromosomes at such high frequency in cervical cancer-derived cells may reflect events that are relevant to the development of cervical cancer.     

宫颈癌中HPV16 E5基因的变异与病毒物理状态的研究

目的研究HPV16DNA在宫颈癌组织中的物理状态及其与E5转化基因的变异的关系。方法用斑点杂交方法确定HPV16阳性的宫颈癌标本,采用Southern印记杂交技术检测HPV16DNA在宫颈癌组织中的物理状态,并结合E5基因的扩增及序列测定来综合探求HPV16基因组在宿主细胞中的物理状态及其与E5片段变异的关系。结果60例宫颈癌组织中HPV16阳性率为58%(35/60);其中有22%(8/35)的HPV16DNA是以游离状态存在于宿主细胞内。在HPV16以游离型存在的宫颈癌标本中,仅有1例(1/8)发生了变异。结论不同病理分期的宫颈癌组织HPV16的物理状态无明显差异。在游离型HPV16致癌机制中,E5的变异似乎不占主导地位。所得结果为揭示HPV16致宫颈癌的分子机制尤其是为E5在游离型HPV16致癌机制提供了新资料。     

HPV infection in cervical-cancer cases in Russia

The presence of human papillomavirus (HPV) sequences in 21 biopsies from cervical carcinomas, II specimens of tissues adjacent to tumours, 2 specimens of cervical tissues with radiation fibrosis from patients after radiation therapy of cervical cancer and 7 normal epithelial tissues from the patients with other genital tumours were examined by polymerase chain reaction (PCR) and Southern-blot analysis. All tumours were HPV-positive by type-specific PCR and 86% by Southern-blot analysis. In normal epithelial and adjacent tissues, HPV sequences were detected in 20% of samples by Southern-blot analysis and in 70% of samples by PCR, including 2 cases of tissues after radiation therapy. HPV 16 was the most prevalent type in tumours (18/21) as well as in normal epithelial tissues (5/7). One HPV-positive tumour contained HPV18 DNA and 2 were doubly infected with HPVs 16 and 18 (2/21). The persistence of exclusively episomal HPV16 DNA was observed in 5 out of 11 tumours examined: 3 cases of squamous-cell carcinomas on the early stage of tumour progression and 2 advanced tumours (squamous-cell carcinoma and adenocarcinoma). The integration of HPV16 genome was detected in 6 out of 11 tumours, but most of them contained episomal forms of viral DNA simultaneously (5 out of 6). The integrative HPV18 genome was found in 2 tumours examined, and the persistence of episomal forms was also observed in one of them. Our data demonstrate that cervical tumours are associated invariably with high-risk types of HPV in Russia. © 1995 Wiley-Liss, Inc.     

利用FISH分析HPV16在Hela细胞中的整合位点

 目的 探讨HPV16病毒感染导致子宫颈癌发生的染色体畸变。方法 利用荧光原位杂交（FISH）技术检测HPV16病毒感染导致的Hela细胞中染色体核型的变化。结果 Hela细胞系中存在9号染色体的三体畸变，但3号染色体表现为正常的二倍体核型；Hela细胞中没有发现HPV16的整合位点，但当外源性的HPV16感染Hela细胞后，HPV16病毒DNA整合在3号染色体上；9号和3号染色体变异在子宫颈癌的发生发展中起着重要的作用，而HPV16的感染主要引起3号染色体的变异。结论 HPV16可以引起Hela细胞的3号染色体的畸变，从而导致子宫颈癌的发生。     

HPV prevalence, viral load and physical state of HPV-16 in cervical smears of patients with different grades of CIN

Human papillomavirus (HPV) infection is the most important event in malignant transformation of human cervical epithelium. We analysed in cervical smears, HPV genotypes with a focus on single/multiple infections, then characteristics of HPV-16 infections (presence of other genotypes, viral load and physical state) according to the grade of histological lesions. The purpose of this study was to know if these parameters could allow to differentiate histological diagnoses. DNA was extracted from 363 cervical samples corresponding to 24 cases without lesion, 96 CIN1, 92 CIN2, 144 CIN3 and 7 cancers. Our results show that HPV-16 was predominant and its prevalence increased with the severity of lesions (CIN1: 27.1%; CIN3: 65.3%). In addition, we showed that the frequency of single infections, as compared with multiple infections, increased with the severity of the lesion (CIN1: 25.0%; CIN3: 54.8%). Among HPV-16 positive samples (n = 170), we found that viral load, determined on cervical samples by real-time PCR, did not vary significantly according to the different CIN grades. Concerning HPV-16 integration, the mixed and integrated HPV-16 forms, already present in women with normal histology, increased to the benefit of pure episomal forms with the severity of lesions (normal cervix: 28.6%; CIN3: 73.8%). Thus, our data raise the question of the viral load as a valuable clinical parameter to discriminate between lesion grades. Moreover, we emphasize integration as an early event in cervical carcinogenesis, increasing with the severity of lesions. Finally, this study underlines the importance of single versus multiple infections linked to the severity of CIN.     

多重实时PCR在宫颈癌及癌前病变HPV-16病毒存在状态检测中的应用

Objective: To explore an ideal approach for detecting the physical status of HPV-16 in clinic use and to investigate the integrated HPV-16 in CINs and cervical cancer. Methods: Multiplex real-time PCR method was established to quantify the copy numbers of E2 and E6 genes (E2/E6) for analysis of the physical status of H PV-16 DNA and this assay was compared to Southern blot analysis. HPV-16-containing paraffin-embedded tissues including 49 CINs and 51 cervical squamous cancers were detected using the method. Results: (1) The cutoff ratio of E2/E6 to distinguish pure episomal from mixed H PV-16, was0.81 in the multiplex real-time PCR; (2) The agreement rate between multiplex real-time PCR and Southern blot was 81.5%(the Kappa statistic was 0.844, P＜0.001); (3) HPV-16 DNA existed in an episomal form in 57.1% and mixed form in 42.9%of CIN Ⅰ lesions; The concomitant form of HPV-16 (＞70%) constituted the majority in CIN Ⅱ and CIN Ⅲ; HPV-16 DNA mostly integrated into the host chromosome (s) in squamous cervical cancers (68.6%); (4) The incidence of HPV-16 integration was increased with the degree of cervical lesions; (5) The frequency of pure integrated HPV-16 in stage Ⅱ Ⅲ (88%) was significantly higher than that in stage Ⅰ (33.3%). Conclusion: (1) Mutiplex real-time PCR provides a rapid, sensitive and reliable method for clinic detection of the physical state of HPV-16 DNA; (2) The integration of the HPV-16 DNA is a very early and important event in the progression from preinvasive to invasive cervical cancer; (3) The pure integrated status of HPV-16 in cervical cancer may be associated with poor prognosis of cervical cancer, but further study will be needed to prove its prognostic significance.     

HPV in situ hybridization: impact of different protocols on the detection of integrated HPV

Although there is consensus that HPV integration is common in invasive cervical carcinomas and uncommon or absent in low-grade uterine cervical intraepithelial neoplasia (CIN I), estimates for HPV integration in CIN II/III range from 5 to 100% using different PCR-based and in situ hybridization (ISH) approaches. It has been suggested that HPV integration can be identified using ISH by scoring of punctate signals. The increased sensitivity of fluorescence ISH (FISH) methods, allowing the detection of single copies of HPV, complicates the distinction between integrated and episomal HPV. Recently it has been suggested that, in such assays, the signals originating from integrated virus can be hidden in a background of episomal HPV. We therefore compared 2 different FISH protocols for the detection of integrated HPV in a series of CIN II/III lesions: 1) a mild protocol in which episomal HPV and RNA is retained and 2) a harsh protocol that extensively extracts proteins and RNA, and which promotes the partial loss of episomal HPV but not integrated HPV. A series of 28 HPV 16/18 positive CIN II/III lesions (17 solitary lesions and 11 lesions adjacent to microinvasive carcinoma) were studied. A punctate signal pattern was identified in 7 of these lesions with both protocols. Punctate signal was also present in control samples from lesions that are known to be associated with HPV integration (invasive squamous cell carcinoma (n = 3), adenocarcinoma in situ (n = 3), and invasive adenocarcinoma (n = 1). HPV RNA contributed significantly to the intensity of punctate FISH signal, especially when applying the mild protocol, as shown by omitting DNA denaturation, including RNase pretreatment steps and measuring the fluorescence signal intensity. Also, HPV RNA was frequently detected in addition to episomal/integrated HPV DNA in the majority of the other 21 CIN II/III lesions; this resulted in intense granular/diffuse FISH signals throughout the epithelium. However, in 7 of these lesions, the harsh protocol gave a more consistent punctate pattern in cells throughout the full thickness of the epithelium. This supports the hypothesis that the harsh protocol unmasks integrated HPV more efficiently by extracting RNA and episomal HPV. Overall, with this harsh protocol, a clonally expanded population of cells containing punctate HPV signals was found in 5 of 17 (29%) solitary CIN II/III lesions and in 9 of 11 (88%) CIN II/III lesions associated with microinvasive carcinoma. Combining these data with the results from our previous study, with the harsh protocol in 7 of 40 (18%) solitary CIN II/III lesions and 19/21 (90%) CIN II/III lesions associated with microinvasive carcinoma (p < 0.001), this pattern was found. This indicates that, when robustly defined, a punctate HPV pattern in CIN II/III lesions is associated with the presence of an invasive carcinoma.     

Physical status of HPV types 16 and 18 in topographically different areas of genital tumours and in paired tumour-free mucosa

HPV16 and HPV18 integration into host cell DNA contributes to malignant transformation. Viral physical status was compared among samples from different tumour areas, and from tumour and paired non-lesional adjacent epithelium, in order to evaluate the levels of HPV integration that could account for local recurrences. Fifty-nine surgical biopsies were collected from 24 women with HPV16 and/or HPV18-associated genital tumours, including 3 preinvasive and 21 invasive lesions. HPV integration was analysed by type-specific and multiplex PCRs for E6, E1 and E2 sequences. Nine tumours contained HPV16, 1 HPV18 and 14 both viruses. Intra-tumour heterogeneity occurred in 3 of the 10 tumours with multiple sampling (30%), including different HPV16 physical forms between core and periphery in 2 cases, and different type of HPV infection in 1 case. Almost all tumours contained integrated forms of either HPV16 and/or HPV18. Analysis of the 15 tumour-free tissues displayed 11 HPV-positive (73%) and 4 HPV-negative tissues. HPV16 was pure integrated in 1 case, mixed in 1 and episomal in 8, whereas HPV18 was integrated in all 6 positive tissues (100%). When compared to the corresponding tumour, the positive control mucosa contained the same HPV type and the same physical status as the tumour in 6 cases, whereas 5 samples contained different HPV16 physical forms, episomal DNA being more frequent than in the lesion. These data showing the presence of high-risk HPV integrated forms in normal mucosa, especially in HPV18-positive cases, indicate that the research of viral integration in the adjacent tumour tissues may be a valuable tool in assessing risk factors for local recurrences.     

Human papillomavirus 16 dna in cervical cancers and in lymph nodes of cervical cancer patients: A diagnostic marker for early metastases?

Human papillomavirus (HPV) 16 is most prevalent in cervical cancers and also persists in metastases. We examined HPV16-DNA-positive primary cancers and several lymph nodes from each of 14 patients to evaluate the use of HPV16 DNA as a diagnostic marker for the detection of early node involvement. The HPV16 DNA was exclusively integrated in 39% of the primary cancers, predominantly episomal in 36%, and integrated and extrachromosomal to a similar extent in 25%. Thirteen of 16 involved lymph nodes contained HPV16 sequences. Integrated viral DNA showed the same pattern in primary tumors and in metastases. The level of extrachromosomal HPV16 DNA, however, appeared to be considerably reduced in some nodes. HPV16 DNA was also detected in 18 out of 59 histologically negative lymph nodes. This result recommends nucleic acid hybridization as a sensitive method for the detection of HPV-DNA-positive cancer cells. The prognostic significance of viral sequences in histologically negative nodes remains to be established.     

The physical state of human papillomavirus type 16 DNA in cervical carcinomas of Hong Kong Chinese.

The presence of human papillomavirus (HPV) in 15 cervical carcinoma specimens obtained from Hong Kong Chinese patients was analyzed by Southern blot hybridization studies. In nine (60%) of them, HPV 16 genomes were detected, while two others (13.3%) were found to harbor HPV DNA of unknown type closely related to HPV 16. All of them were classified as squamous cell carcinomas according to WHO guidelines. In addition, the presence of HPV 18 was shown in another two (13.3%) squamous cell carcinoma samples. Among the nine tumors harboring HPV 16, four specimens (44.4%) have HPV in integrated forms, while four others (44.4%) have HPV in episomal forms. The simultaneous presence of both episomal and integrated forms was demonstrated in the remaining tissue sample (11.2%). The result obtained here indicates a strong association between HPV infection and cervical carcinogenesis in Hong Kong Chinese, with HPV 16 prevalent in squamous cell carcinoma. Moreover, the persistence of HPV 16 episomes in some of the tumor specimens suggests that extrachromosomal HPV DNA, possibly acting synergistically with other oncogenic factors, is also capable of inducing cervical cancer.     

Prevalence and physical status of human papillomavirus in squamous cell carcinomas of the head and neck

Fresh-frozen biopsies were obtained from 61 patients at diagnosis of squamous cell carcinoma of the head and neck (HNSCC) for study of the prevalence and physical status of human papillomavirus (HPV) DNA. The frequency of HPV DNA and genotypes were determined by SPF10 PCR screening with a general probe hybridization and INNO-LiPA HPV genotyping assay. In addition, a single-phase PCR with primers FAP 59/64 and a nested PCR with primers CP 65/70 and CP 66/69 served to detect particularly cutaneous HPV types. By the sensitive SPF10 PCR and INNO-LiPA assay, 37 of 61 (61%) samples were positive for HPV. HPV-16 was the most frequently detected type (31 of 37, 84%). Multiple infections were found in 8 of 37 (22%) of the HPV-positive samples, and co-infection by HPV-16 and HPV-33 was predominant. No cutaneous HPV types were detected. Patients with HPV-positive tumors had similar prognosis as those with HPV-negative ones. Real-time PCR analysis of the HPV-16 positive samples indicated the presence of integrated (11 of 23, 48%), episomal (8 of 23, 35%) and mixed forms (4 of 23, 17%) of HPV DNA. The viral load of HPV DNA exhibited large variation. The median copy numbers of E6 DNA in tonsillar specimens were approximately 80,000 times higher than that in nontonsillar HNSCC ones. Patients with episomal viral DNA were more frequently found to have large (T3-T4) tumors at diagnosis than were those with integrated or mixed forms.     

Integration Sites and Genotype Distributions of Human Papillomavirus in Cervical Intraepithelial Neoplasia

Objectives: To analyse HPV integration prevalence and genotype distributions in cervical intraepithelialneoplasia (CIN) in east part of China, furthermore to assess preferential sites for common HPV integrations andprovide baseline information for cervical abnormality screening and prevention. Methods: Integration of HPV in113 paraffin-embedded cervical intraepithelial neoplasia samples was assessed using Gencap technology in KeyLaboratory of Biotechnologies in BGI-Shenzhen. Results: 64 samples were HPV-integrated and as the cervicallesions increased, the integration rate became higher significantly (P=0.002). Fifteen different HPV genotypeswere detected, 14 high-risk (16, 18, 31, 33, 51, 52, 56, 58, 66, 68) and 1 low-risk (11). The most common genotypeswere HPV-16, 58, 33, 52, 66, and 56. Thirteen patients had co-integration involving mainly HPV-16 and 58. Thefrequency of HPV gene disruption was higher in L1 and E1 genes than in other regions of the viral genomes.Conclusion: Some 56.6% of CIN lesions in Qingdao had HPV integrations, and 67.2% of HPV-integrated patientswere HPV-16 and 58, more prone to be integrated in younger patients below 45 years old. There exist preferentialsites for HPV-16 and HPV-58 integration, and they are more likely to be disrupted in the L1 and E1 loci.