Factor analysis of confocal image sequences of human papillomavirus DNA revealed with fast red in cervical tissue sections stained with TOTO-iodide

OBJECTIVE: To visualize and localize specific DNA sequences by fluorescence in situ hybridization, confocal laser scanning microscopy (CLSM) and factor analysis of biomedical image sequences (FAMIS). STUDY DESIGN: Human papillomavirus (HPV) DNA was identified in cervical tissue sections with biotinylated DNA probes recognizing the whole genome of HPV DNA types 18 and 16, and DNA-DNA hybrids were revealed by streptavidin-alkaline phosphatase and Fast Red (FR). Cell nuclei were counterstained with TOTO-iodide. Image sequences were obtained using successive dynamic or spectral sequences of images on different optical slices from CLSM. The location of fluorescent signals inside tissue preparations was determined by FAMIS and/or selection of filters at emission. Image sequences were summarized into a reduced number of images, called "factor images," and curves, called "factors." Factors estimate spectral patterns and depth emission profiles. Factor images correspond to spatial distributions of the different factors. RESULTS: We distinguished between FR and nucleus staining in HPV DNA hybridization signals by taking into account differences in their spectral patterns and improved visualization by taking into account differences in their focus (depth emission profiles). CONCLUSION: FAMIS, together with CLSM, made possible the detection and characterization of HPV DNA sequences in cells of cervical tissue sections.     

Single-copy gene detection using branched DNA (bDNA) in situ hybridization.

We have developed a branched DNA in situ hybridization (bDNA ISH) method for detection of human papillomavirus (HPV) DNA in whole cells. Using human cervical cancer cell lines with known copies of HPV DNA, we show that the bDNA ISH method is highly sensitive, detecting as few as one or two copies of HPV DNA per cell. By modifying sample pretreatment, viral mRNA or DNA sequences can be detected using the same set of oligonucleotide probes. In experiments performed on mixed populations of cells, the bDNA ISH method is highly specific and can distinguish cells with HPV-16 from cells with HPV-18 DNA. Furthermore, we demonstrate that the bDNA ISH method provides precise localization, yielding positive signals retained within the subcellular compartments in which the target nucleic acid sequences are localized. As an effective and convenient means for nucleic acid detection, the bDNA ISH method is applicable to the detection of cancers and infectious agents. (J Histochem Cytochem 49:603-611, 2001)     

宫颈癌病变组织人乳头瘤病毒感染率的免疫细胞化学与DNA杂交的比较观察

近年来人乳头瘤病毒（ＨＰＶ）被认为与宫颈癌的发生有密切关系。该实验报道了用分子杂交技术（在严格条件下）检测了宫颈活检组织：慢性宫颈炎、宫颈上皮内瘤（ＣＩＮ）、宫颈癌和宫颈正常组织中１６型乳头瘤病毒（ＨＰＶ－１６）ＤＮＡ的阳性率,并将其与用免疫细胞化学方法（ＰＡＰ）所得结果进行了比较。结果显示１３％（２／１５）的慢性宫颈炎、１７％（２／１２）的ＣＩＮ、５６％（５１／９１）的宫颈癌含有ＨＰＶ－１６ＤＮＡ,而正常组织为阴性;ＨＰＶ属抗原仅见于３５％（６／１７）的ＣＩＮ,其他受检组织均为阴性。结果提示用ＰＡＰ法检查ＨＰＶ－１６的抗原,所得阳性率不及ＤＮＡ杂交所得阳性率高;但它作为一种简便、快速的方法用于福尔马林固定、石腊切片材料,显示ＨＰＶ属抗原,借以筛选多种不同型的ＨＰＶ对ＣＩＮ或其他组织中ＨＰＶ的增殖性感染有一定的价值。     

Use of Antibodies Against A Synthetic Peptide of the E6 Protein of Human Papillomavirus (Hpv) Type 16 For the Diagnosis of Genital Hpv Lesions

The E6 open reading frame of the human papillomavirus (HPV) 16 codes for a protein of 158 amino acids with a theoretical molecular weight of 19.1 kD. A peptide corresponding to 147–158 amino acids (NH₂-RSSRTRRETQLC-COOH) was synthesized, coupled to haemocyanin and used for immunization of rabbits. the antibodies obtained were used for the immunohistochemical analysis of a series of 41 paraffin-embedded biopsies including 29 cases of HPV 16-associated cervical lesions, five HPV 6, four HPV 11, and three HPV 18-associated genital warts. Expression of a reacting molecule (both intranuclear and cytoplasmic) could be demonstrated in 28/29 (96.6%) of the HPV 16 lesions, in 2/5 (40%) of the HPV 6, in 2/4 (50%) of the HPV 11, and in 3/3 of HPV 18 lesions. the intensity of the staining was weak in the HPV 6 and HPV 11 lesions, whereas it was classified as intense in 21/29 (72%) of the E6-positive HPV 16 lesions. Negative staining was almost invariably (5/6, 83%) confined to HPV-non-cervical intraepithelial neoplasia (HPV-NCIN) lesions, only 5/18 (27%) of which showed an intense staining. In contrast, intense staining was associated with CIN; 11/12 (92%) in HPV-CINI and 8/11 (73%) in HPV-CINII lesions. In the HPV 16 group, intense reactivity was more frequent in lesions shown to make clinical progression (8/9,89%) as compared with those which underwent spontaneous regression (10/15,66.7%). Topography of the immunostaining paralleled the localization of HPV DNA hybridization signals in 20/21 (95%) evaluable HPV 16 cases, in contrast to only 1/3 in HPV 18 cases and in none of the HPV 6 and HPV 11 lesions. These differences between HPV 16 and HPV 6/11 lesions in the staining with the HPV 16 E6 protein antibody might help explain at least some of the differences in their known biological behaviour.     

宫颈癌患者人乳头瘤病毒(HPV)主要型别及其感染研究

本文探讨了江西省和广东省宫颈癌患者人乳头瘤病毒(Human papillomavirus,HPV)感染及其型别分布,分析了高危型HPV对各种宫颈病变的感染情况,为宫颈癌的早期发现和临床诊治提供科学依据。首先采用细胞学、HPV DNA检测(第二代杂交捕获法,HC2)、电子阴道镜和宫颈化学着色方法筛查宫颈癌患者,经病理镜检确诊,然后用GP PCR-SBT法对宫颈癌患者进行HPV基因分型。江西省溪口镇、古市镇及修水县城宫颈癌癌前病变发生率为5．7‰。HC2方法发现宫颈癌患者13种高危型HPV DNA阳性率为89．9％,宫颈上皮内瘤样病变的为84．8％,对照组为24．5％。采用GP PCR-SBT方法进行基因分型发现,江西省宫颈癌患者存在HPV16、58、31、33、18、66、6、11、56和81十种型别,其中HPV81型在国内外鲜有报道。据此提出生殖道高危型HPV感染是妇女宫颈癌发病的重要因素。并发现江西省宫颈癌高发区妇女高危型HPV感染率为24．5％。建立了HPV基因分型的方法,对HPV致宫颈病变的分子机制进行了分析。     

Sensitivity of HPV tests on stained vs. unstained cervical smears

OBJECTIVE: To examine the effect of Pspanicolaou staining of cervical smears on the sensitivity of molecular biologic HPV tests. STUDY DESIGN: Two sensitive HPV tests were used, HPV DNA sequence analysis after polymerase chain reaction (PCR) amplification and the Hybrid Capture II method (HC II) (Digene Diagnostics Inc., Silver Spring, Maryland, USA). Papanicolaou-stained and unstained smears taken simultaneously were examined from 265 women readmitted for examination due to an atypical squamous cells of undetermined significance diagnosis. RESULTS: After an HPV test with the PCR method on unstained slides, 66% of the women were HPV positive, whereas the same women were HPVpositive in 54% when Papanicolaou-stained slides were analyzed. However, this difference was not statistically significant (p > 0.1). With the HC II method, 55% of unstained smears were HPV positive whereas 29% were HPV positive, when Papanicolaou-stained slides were examined. This difference was significant (p < 0.001). The same strong differences in sensitivity were observed when both the PCR and HC II methods were studied on the same Papanicolaou stained glass slides, whereas on unstained slides no significant difference was found. CONCLUSION: The results demonstrate that Papanicolaou staining of a cervical smear significantly decreases the sensitivity of an HPV test performed with the HC II method, whereas the PCR method is less affected. With the Papanicolaou method, the hematoxylin bath is followed by HCl treatment, and strong acid treatment destroys DNA.     

Analysis of the physical state of different human papillomavirus DNAs in intraepithelial and invasive cervical neoplasm.

The integration of human papillomavirus (HPV) DNA into the human genome has been generally accepted as a characteristic of malignant lesions. To gain a better understanding of this phenomenon, genomic DNA from 181 cervical biopsy specimens was isolated and analyzed for HPV type and physical state of the HPV genome. These specimens represented the full spectrum of cervical disease, from condyloma to invasive carcinoma. Discrimination between integrated and episomal HPV DNA was accomplished by the detection of HPV-human DNA junction fragments on Southern blots. In most cases in which ambiguous Southern blot results were obtained, the specimens were reanalyzed by two-dimensional gel electrophoresis. Of the 100 biopsy specimens of cervical intraepithelial neoplasia analyzed, only 3 showed integrated HPV DNA, in contrast to 56 (81%) of 69 cervical carcinomas (P less than 0.001) showing integrated HPV DNA. Of the 40 carcinomas containing HPV 16 DNA, 29 (72%) had integrated HPV DNA, of which 8 (20%) also had episomal HPV DNA. In 11 (27%) cancers, only episomal HPV 16 DNA was detected. All 23 HPV 18-containing carcinomas had integrated HPV DNA, and 1 also had episomal HPV 18 DNA. The difference between HPV types 16 and 18 with respect to frequency of integration was statistically significant (P less than 0.01). The results of this study indicate that detectable integration of HPV DNA, regardless of type, occurs infrequently in cervical intraepithelial neoplasia. The absence of HPV 16 DNA integration in some carcinomas implies that integration is not always required for malignant progression. In contrast, the consistent integration of HPV 18 DNA in all cervical cancers examined may be related to its greater transforming efficiency in vitro and its reported clinical association with more aggressive cervical cancers.     

Use of sulfonated primers to detect and type papillomavirus in cell cultures and cervical biopsies.

Human papillomavirus (HPV) was detected by using two sets of deoxyribonucleotide primers for differentiating between 'low-risk' types (HPV11 and HPV6) and 'high-risk' (hri) types (HPV16, HPV18 and HPV33). A new application of the Chemiprobe method for labeling DNA was used to detect products of the polymerase chain reaction (PCR) from 36 cervical biopsies. This method, first demonstrated by Uchimura et al. (submitted), is based on the sulfonation of a polycytidylic acid tail of 5-20 monomers attached to the 5' end of either one or both of the PCR primers. This procedure can increase the sensitivity of detection of PCR products more than 100-fold with respect to ethidium bromide (EtdBr) staining. Various methods were used to detect hri HPV DNA in the 36 clinical samples. The number of positive results obtained was as follows, two by Southern-blot hybridization; five by PCR amplification followed by electrophoresis and detection of products by EtdBr staining; six by PCR amplification using one or two sulfonated C-tailed primers followed by electroblotting and immunoenzymatic visualization; and five by hybridization of sulfonated genomic viral recombinant with a PCR product immobilized on a membrane. The yield of the PCR product was significantly greater when one of the primers was C-tailed than when both or neither of the primers were C-tailed. PCR employing sulfonated C-tailed oligo primers is very specific and sensitive, and the entire procedure can be employed as a nonradioactive substitute for radioactive dot-blot or Southern-blot hybridization procedures, routinely used for detection of HPV in clinical samples.     

空泡细胞在诊断宫颈人乳头瘤病毒感染中的意义

本文对空泡细胞(Koilocyte)的形态进行了光镜和电镜观察,并应用分子杂交技术和PAP染色的方法对宫颈疾患中人乳头瘤病毒(HPV)DNA和抗原进行了检测,分析HPV DNA及抗原检测结果与空泡细胞出现的关系发现,空泡细胞阳性的病例中HPV DNA及抗原的检出率较低,并且部分空泡细胞阳性的病例中也可测出疱疹病毒Ⅱ型(HSV_2)抗原,结果提示:空泡细胞并不是HPV感染所特有的,空泡细胞作为诊断宫颈HPV感染的特征性指标值得怀疑。     

Conservation of E6 and E7 regions of human papillomavirus types 16 and 18 present in cervical cancers

The E6 and E7 regions of human papillomavirus (HPV) type 16 were present in the DNA samples from cervical cancer cell lines, SKG-IIIa and SKG-IIIb, and those from cervical cancer tissues of three different patients. T601 cells, an NIH3T3 transformant obtained by transfection of DNA from a surgical specimen of a cervical cancer, also contained the E6 and E7 regions. The E6 region of HPV type 16 was expressed as mRNA in SKG-IIIa, SKG-IIIb and T601 cells. The E6 and E7 regions of HPV type 18 were present in the DNA samples from cervical cancer cell lines, SKG-I and SKG-II, and those from cervical cancer tissues of two different patients. SKG-I and SKG-II cells expressed the E6 region of HPV type 18 as mRNAs. These results strongly suggest that the E6 and E7 regions or the sequence surrounding these regions are important for maintaining malignant phenotype of cervical cancer cells.     

Identification of multiple HPV types on spermatozoa from human sperm donors

Human papillomaviruses (HPV) may cause sexually transmitted disease. High-risk types of HPV are involved in the development of cervical cell dysplasia, whereas low-risk types may cause genital condyloma. Despite the association between HPV and cancer, donor sperm need not be tested for HPV according to European regulations. Consequently, the potential health risk of HPV transmission by donor bank sperm has not been elucidated, nor is it known how HPV is associated with sperm. The presence of 35 types of HPV was examined on DNA from semen samples of 188 Danish sperm donors using a sensitive HPV array. To examine whether HPV was associated with the sperm, in situ hybridization were performed with HPV-6, HPV-16 and -18, and HPV-31-specific probes. The prevalence of HPV-positive sperm donors was 16.0% and in 66.7% of these individuals high-risk types of HPV were detected. In 5.3% of sperm donors, two or more HPV types were detected. Among all identified HPV types, 61.9% were high-risk types. In situ hybridization experiments identified HPV genomes particularly protruding from the equatorial segment and the tail of the sperm. Semen samples from more than one in seven healthy Danish donors contain HPV, most of them of high-risk types binding to the equatorial segment of the sperm cell. Most HPV-positive sperm showed decreased staining with DAPI, indicative of reduced content of DNA. Our data demonstrate that oncogenic HPV types are frequent in men.     

The early detection of cervical cancer. The current and changing landscape of cervical disease detection

Cervical cancer prevention has undergone dramatic changes over the past decade. With the introduction of human papillomavirus (HPV) vaccination, some countries have seen a dramatic decline in HPV‐mediated cervical disease. However, widespread implementation has been limited by economic considerations and the varying healthcare priorities of different countries, as well as by vaccine availability and, in some instances, vaccine hesitancy amongst the population/government. In this environment, it is clear that cervical screening will retain a critical role in the prevention of cervical cancer and will in due course need to adapt to the changing incidence of HPV‐associated neoplasia. Cervical screening has, for many years, been performed using Papanicolaou staining of cytology samples. As our understanding of the role of HPV in cervical cancer progression has advanced, and with the availability of sensitive detection systems, cervical screening now incorporates HPV testing. Although such tests improve disease detection, they are not specific, and cannot discriminate high‐grade from low‐grade disease. This has necessitated the development of effective triage approaches to stratify HPV‐positive women according to their risk of cancer progression. Although cytology triage remains the mainstay of screening, novel strategies under evaluation include DNA methylation, biomarker detection and the incorporation of artificial intelligence systems to detect cervical abnormalities. These tests, which can be partially anchored in a molecular understanding of HPV pathogenesis, will enhance the sensitivity of disease detection and improve patient outcomes. This review will provide insight on these innovative methodologies while explaining their scientific basis drawing from our understanding of HPV tumour biology.     

DNA sequences of human papillomavirus types 11, 16, and 18 in lesions of the uterine cervix in the west of Scotland.

Punch biopsy specimens of the cervix were examined both histologically and for the presence of human papillomavirus (HPV) DNA sequences. The presence of HPV DNA sequences was sought with the Southern blot technique using radioactively labelled HPV-6, 11, 16, and 18 DNA probes, both together and separately. Twenty six biopsy specimens were examined. Histological examination showed cervical intraepithelial neoplasia grade 2 or 3 in 16 specimens, viral changes (koilocytosis) in four, and inflammation or a normal appearance in three. Eleven specimens were negative for HPV DNA sequences, 10 contained HPV-16 DNA, four contained HPV-18 DNA, and one contained both HPV-18 and HPV-11 DNA. Episomal HPV-16 DNA was detected in one case of cervical intraepithelial neoplasia grade 3 and in five cases of cervical intraepithelial neoplasia grade 2/3 with koilocytosis; and episomal HPV-18 DNA was found in two specimens classed as cervical intraepithelial neoplasia grade 2/3, one of which also contained HPV-11 DNA, and in one specimen that showed viral changes alone. Integrated HPV DNA was found in six specimens (four with HPV-16 DNA and two with HPV-18 DNA), including two cases of chronically inflamed cervix with no histological evidence of viral infection or cervical intraepithelial neoplasia. Detection of viral DNA in early lesions may identify patients at risk of malignant progression. This is the first report of HPV-18 DNA in cervical intraepithelial neoplasia in Scotland.     

Histological and cytological evidence of viral infection and human papillomavirus type 16 DNA sequences in cervical intraepithelial neoplasia and normal tissue in the west of Scotland: evaluation of treatment policy

Biopsy samples from 27 patients referred to a colposcopy clinic in Glasgow for cervical abnormalities were assessed for the relations among colposcopic appearances, cytological and histological diagnosis, expression of papillomavirus antigen, and the presence of human papillomavirus (HPV) types 6, 11, 16, and 18 deoxyribonucleic acid (DNA) sequences. Specimens were from colposcopically abnormal areas of the transformation zone and from colposcopically apparently normal areas of the zone in the same patients (paired matched internal control tissue). All 27 women referred for abnormal smears had colposcopic abnormalities.HPV-16 or 18 DNA sequences were detected in 20 of the 27 colposcopically abnormal biopsy samples and 13 of the 27 paired normal samples. Twelve samples of colposcopically normal tissue contained histological evidence of viral infection but only four of these contained HPV DNA sequences. The other nine samples of colposcopically normal tissue which contained HPV DNA sequences were, however, histologically apparently normal. HPV-6 and 11 were not detected.Integration of the HPV-16 genome into the host chromosome was indicated in both cervical intraepithelial neoplasia and control tissues. In two thirds of the HPV DNA positive samples the histological grade was classed as normal, viral atypia, or cervical intraepithelial neoplasia grade 1. Papillomavirus antigen was detected in only six of the abnormal and three of the normal biopsy samples, and HPV DNA was detected in all of these.The detection of HPV DNA correlates well with a combination of histological and cytological evidence of viral infection (20 of 22 cases in this series). A poor correlation between the site on the cervix of histologically confirmed colposcopic abnormality and the presence of HPV DNA sequences implies that a cofactor other than HPV is required for preneoplastic disease to develop.A separate study in two further sets of biopsy samples examined the state of HPV DNA alone. The sets were (a) 43 samples from cervical intraepithelial neoplasia and nine external controls and (b) 155 samples from cervical intraepithelial neoplasia, cervical cancer, vulval intraepithelial neoplasia, and vulval cancer and external controls. HPV-11 was found in only two (4·7%) of the 43 specimens from cervical intraepithelial neoplasia, whereas HPV-16 was found in 90 (58%) of the other 155 specimens. These results also suggest that HPV subtype is subject to geographical location rather than being an indicator of severity of the lesion or of prognosis.     

Human papillomavirus DNA and liquid-based cervical cytology cotesting in screening and follow-up patient groups

OBJECTIVE: To compare the use of human papillomavirus (HPV) DNA and cervical cytology cotesting in screening and follow-up of patients with previous cervical abnormalities and to assess the significance of a positive HPV DNA test result in re-screening of cytologically normal cases. STUDY DESIGN: Cellular samples collected in liquid-based fixative were used for both cervical cytology and HPV DNA testing. The cervical cytology slides were manually screened by cytotechnologists followed by rapid re-screening by pathologists. The HPV DNA tests were performed using hybrid capture test kits. Statistical analyses of cervical cytology results and HPV DNA tests for high- and low-risk HPV from both patient groups were carried out. RESULTS: The prevalence of HPV DNA-positive cases was higher in younger patients. There was a poor correlation between cervical cytology results and HPV DNA tests for the screening group (kappa = 0.23), but a fair to good correlation was obtained for the follow-up group (kappa = 0.51). The false negative fraction of cytology negative/HPV DNA positive cases (0.1317), as compared with cytology negative/HPV DNA negative cases (0.0056), was statistically significant (p = 0.000001). CONCLUSION: The prevalence of HPV DNA decreased with increasing age in both the screening and follow-up patient groups. Virus clearance was delayed in the follow-up group as compared with the screening group. There was a poor correlation between cervical cytology and HPV DNA tests in the screening group but a fair to good correlation in the follow-up patient group. Cotesting of HPV DNA and cervical cytology increases the sensitivity and decreases the false negative fraction, suggesting that cotesting could be used to increase the interval of screening.     

Association of human papillomavirus type 16 E7 and HLA class I antigen expression in cervical premalignant and malignant lesions

In the present experiment we studied the correlation between HPV16 infection and expression of HLA-I antigen in cervical premalignant and malignant lesions (cervicitis, CIN, cervical squamous carcinomas and adenocarcinoma samples). The HPV16 E7 DNA load and the expression of HLA-I antigen in the samples were measured by real-time fluorescence quantitative polymerase chain reaction (RFQ-PCR) and immunohistochemical S-P staining, respectively. Our data indicate that HPV16 E7 load was highly and positively associated with the development of cervical lesions (Spearman's correlation coefficient r=0.848, p<0.001), the negative rate of HLA-I antigen was significantly distinguished among groups (p<0.001), and HPV16 E7 infection and downregulation of HLA-I antigen were highly correlated in cervical lesions (Pearson's correlation coefficient r=-0.487, p<0.001). HPV16 E7 may play an important role in the downregulation of HLA-I antigen in cervical lesions, which results in the immune escape of the virus and the occurrence, development, invasion and metastasis of cancer. Furthermore, quantitative PCR for HPV16 E7 may play an important role in the early detection of cervical diseases and in guiding future therapy toward prevention.     

Human papillomavirus DNA detection in Papanicolaou-stained cervical smears with a nonradioactive, in situ hybridization assay.

Archived Papanicolaou-stained cervical smears from women with different cervical pathologies were processed for human papillomavirus (HPV) DNA detection and typing with an in situ hybridization (ISH) assay that employed commercial biotinylated HPV DNA probes. Two HPV DNA probes were utilized: one included HPV genotypes 6/11 and the other, 16/18. The method yielded positive results for HPV DNA 6/11 in 5 cases with condylomata acuminata (100%) and in 2 of 47 with flat warty lesions (4.2%), whereas HPV DNA 16/18 was detected in 29/47 of the latter group (61.7%). In cases with cervical intraepithelial III or invasive squamous cell carcinoma the yield was lower: positive results for HPV DNA 16/18 were obtained in only one of the five cases with one or the other cervical pathology (20%). An analysis of the results showed that the sensitivity of the assay correlated with evidence in the Papanicolaou specimens of pathognomonic cell injury from HPV infection. In the presence of such cytologic features, HPV DNA typing was possible in 37/52 cases (65.4%). In view of the modest difficulty and relatively quick execution of the nonradioactive ISH assay, the authors believe that Papanicolaou cervical smears with cytologic changes of HPV infection could be processed by this method in order to acquire information on the HPV type or types involved in the cervical infection.     

Prevalence of human papillomavirus among Croatian women attending regular gynecological visit

Human papillomavirus (HPV) infection has been identified as major risk factor for cervical intraepithelial neoplasia (CIN) and invasive cervical cancer. About 40 HPV viral types are commonly found in the genital tract. Most HPV infections resolve spontaneously, while persistent infection with oncogenic types, namely HPV 16 and 18 is necessary for CIN to occur and progress to cancer. Cervical screening is presently based on the Pap smear that is designed to diagnose precancerous lesions and cervical cancer The aim of this study was to investigate the prevalence of HPV DNA and to determine HPV types distribution among 361 women attending regular gynecological visit. There were 205 women (29+/-8 years old) without determined abnormal cervical lesions and 156 women (34+/-15 years old) with abnormal Pap smear; low grade squamous intraepitehelial lesions (LSIL, n=69), high grade squamous intraepithelial lesions (HSIL, n=72) and atypical squamous cells of undetermined significance (ASCUS, n=15). HPV DNA detection and genotyping was performed by Hybrid Capture 2 assay and additionally by consensus and type-specific primers directed PCR. The overall prevalence of high-risk HPV (hrHPV) in women with abnormal Pap smears was 67.9% (106/156), of which in ASCUS 33.4% (5/15), LSIL 62.3% (43/69) and HSIL 80.6% (58/72). In HPV positive specimens, HPV 16 was found as predominant type in 60.4% cases, followed by HPV 31 (8.5%), HPV 33 (6.6%) and HPV 18 (3.7%). In the group of women without obvious cervical changes the overall hrHPV prevalence was 35.6% with HPV 16 found in 43.8% cases, followed by HPV 31 (17.8%), HPV33 (9.5%) and HPV18 (6.8%). In both study groups, women with and without cervical lesions, the prevalence of HPVof indeterminate type was 14.2% and 13.7%, respectively. Our results indicate that cervical intraepithelial lesions are largely associated with HPV type 16, followed by HPV types 31, 33, 18 and HPV of indeterminate type. Although there is a significant difference in hrHPV DNA prevalence among two groups, no significant differences between particular hrHPV types distribution were observed.     

Inhibition of cervical carcinoma cell line proliferation by the introduction of a bovine papillomavirus regulatory gene.

Human papillomavirus (HPV) E6 and E7 oncogenes are expressed in the great majority of human cervical carcinomas, whereas the viral E2 regulatory gene is usually disrupted in these cancers. To investigate the roles of the papillomavirus E2 genes in the development and maintenance of cervical carcinoma, the bovine papillomavirus (BPV) E2 gene was acutely introduced into cervical carcinoma cell lines by infection with high-titer stocks of simian virus 40-based recombinant viruses. Expression of the BPV E2 protein in HeLa, C-4I, and MS751 cells results in specific inhibition of the expression of the resident HPV type 18 (HPV18) E6 and E7 genes and in inhibition of cell growth. HeLa cells, in which HPV gene expression is nearly completely abolished, undergo a dramatic and rapid inhibition of proliferation, which appears to be largely a consequence of a block in progression from the G1 to the S phase of the cell cycle. Loss of HPV18 gene expression in HeLa cells is also accompanied by a marked increase in the level of the cellular p53 tumor suppressor protein, apparently as a consequence of abrogation of HPV18 E6-mediated destabilization of p53. The proliferation of HT-3 cells, a human cervical carcinoma cell line devoid of detectable HPV DNA, is also inhibited by E2 expression, whereas two other epithelial cell lines that do not contain HPV DNA are not inhibited. Thus, a number of cervical carcinoma cell lines are remarkably sensitive to growth inhibition by the E2 protein. Although BPV E2-mediated inhibition of HPV18 E6 and E7 expression may contribute to growth inhibition in some of the cervical carcinoma cell lines, the BPV E2 protein also appears to exert a growth-inhibitory effect that is independent of its effects on HPV gene expression.     

Human papillomavirus genotyping by multiplex pyrosequencing in cervical cancer patients from India

Cervical cancer is a leading cause of cancer-related deaths among women in India.Human papillomavirus (HPV) infection is the causative agent of cervical cancer; and infection with the high-risk genotypes, predominantly HPV16 and 18,is the biggest risk factor.Vaccines targeting HPV16 and 18 have been found to confer protection in large- scale clinical trials.HPV genotyping has traditionally been carried out to screen the population "at risk" using indirect methods based on polymerase chain reaction (PCR) using consensus primers combined with various DNA hybridization techniques,and often followed by the sequencing of candidate products.Recently,a high-throughput and direct method based on DNA sequencing has been described for HPV genotyping using multiplex pyrosequencing. We present a pilot study on HPV genotyping of cervical cancer and non-malignant cervical samples using multiplex pyrosequencing.Using genomic DNA from cell lines,cervical biopsies,surgical tissues or formalin-fixed,paraffin- embedded tissue samples,we could successfully resolve 6 different HPV types out of the 7 tested,with their prevalence found to be in agreement with earlier reports. We also resolved coinfections with two different HPV types in several samples. An HPV16 genotype with a specific and recurrent sequence variation was observed in 8 cancer samples and one non-malignant sample. We find this technique eminently suited for high-throughput applications,which can be easily extended to large sample cohorts to determine a robust benchmark for HPV genotypes prevalent in India.