HPV-DNA Copy Research Articles

HPV oncogenes expressed from only one of multiple integrated HPV DNA copies drive clonal cell expansion in cervical cancer.

Persistent oncogenic HPV infections lead to viral DNA integration into the human genome and the development of cervical, anogenital, and oropharyngeal cancers. The expression of the viral E6 and E7 oncogenes plays a key role in cell transformation and tumorigenesis. However, how E6 and E7 could be expressed from the integrated viral DNA which often lacks a viral polyadenylation signal in the cancer cells remains unknown. By analyzing the integrated HPV DNA sites and expressed HPV RNAs in cervical cancer tissues and cell lines, we show that HPV oncogenes are expressed from only one of multiple chromosomal HPV DNA integrated copies. A host polyadenylation signal downstream of the integrated viral DNA is used for polyadenylation and stabilization of the virus-host chimeric RNAs, making the oncogenic transcripts targetable by siRNAs. This observation provides further understanding of the tumorigenic mechanism of HPV integration and suggests possible therapeutic strategies for the development of precision medicine for HPV cancers.

High yield gold nanoparticle-based DNA isolation method for human papillomaviruses genotypes from cervical cancer tissue samples.

Gold nanoparticles (AuNPs) are commonly used in biosensors of various kinds. However, its application to extract DNA from cancer tissues has not been extensively studied. The purification of DNA from cancer tissues is an important step in diagnostic and therapeutic development. Almost, all cervical cancer cases are associated with high-risk human papillomavirus (HR-HPV) infection. Accurate viral diagnosis has so far relied on the extraction of adequate amounts of DNA from formalin-fixed, paraffin-embedded (FFPE) tissue samples. Till now, no specific and sensitive DNA purification method has been introduced for the extraction of HR-HPV from FFPE tissue. Since the commercially available purification kits are not sensitive and specific enough for HR-HPV DNA targets, in this study, a DNA purification method was designed based on AuNPs to purify sufficient amounts of HR-HPV DNA from cervical cancer tissue samples. AuNPs were coated with a series of oligonucleotide probes to hybridize to specific DNA sequences of HR-HPV genotypes. Results showed that 733 out of 800 copies of type-specific HPV DNA were recovered with complete specificity, compared to 36 copies with a standard commercial kit (Qiagen FFPE). The high yield of DNA (91.6%) is the main advantage of the AuNPs-probe purification method.

Multiplexed digital PCR for detection of HPV in tissue samples from oropharyngeal cancer patients.

e17552 Background: p16 immunohistochemistry (IHC) is a commonly used method for identifying HPV-associated oropharyngeal squamous cell carcinoma (OPSCC). However, p16 overexpression in a minority of HPV negative OPSCC can give rise to false positive results. In contrast, HPV nucleic acid testing lacks adequate sensitivity for routine diagnostic testing. The goal of this study was to investigate whether a multiplexed digital PCR assay can detect and quantify HPV DNA in p16 positive OPSCC treated with definitive chemo-radiotherapy (CRT). Methods: Formalin-fixed paraffin embedded (FFPE) residual diagnostic biopsy specimens were collected from 57 patients. Macrodissection was performed to ensure tumor cellularity > 70%. Extracted genomic DNA was analyzed by next generation sequencing (NGS) using a hybrid capture assay (UNCSeq) targeting > 200 cellular genes and HPV 16/18 genomes. We also designed, validated, and implemented an multiplexed droplet digital PCR (dPCR) assay to detect and quantify HPV DNA (strains 16, 18, 31, 33 and 35) in tissue samples, relative to a genomic control locus (chromosome 6). Results: HPV strain 16 DNA was identified in 50 patients (87.7%), whereas 5 patients (8.8%) had HPV DNA from an alternative high-risk strain (18/31/33/35). HPV DNA was undetectable in 2 patients, indicating a false positive rate of 3.5% for p16 IHC testing in this cohort. HPV DNA copy number per diploid genome equivalent varied significantly across samples, with a median value of 19.7 (range 0.23-1712). A significant correlation was observed between the copies of HPV detected by dPCR and NGS (R2 = 0.5853, p < 0.0001). Evidence for HPV integration was detected by NGS in 23 out of 56 evaluable tumors (42%). There was a trend towards a higher prevalence of HPV integration in tumors with less than 10 HPV copies per diploid genome relative to cancers with > / = 10 HPV copy number (63% versus 34%, p = 0.07). Conclusions: Multiplexed digital PCR demonstrates excellent sensitivity for detection and typing of HPV DNA in diagnostic FFPE specimens from patients with p16 positive oropharyngeal cancer. HPV copy number varies significantly across samples, with a possible association with HPV integration status. Future investigations of potential correlation between HPV copy number, integration status, and clinical outcomes are warranted. Clinical trial information: NCT02281955, NCT03077243.

Human papillomavirus detection in urine: Effect of a first-void urine collection device and timing of collection

Great interest has been directed towards the use of first-void (FV) urine as a liquid biopsy for high-risk HPV DNA testing. The aim of this study was to investigate the potential effect of a first generation FV urine collection device on the detection of HPV DNA and to assess if the concentration of HPV DNA varies between FV urine collected in the morning and those collected later during the day. In this prospective cohort study, 33 self-reported HPV-positive women participated. An FV urine sample was collected by these women in the morning (first urine of the day) and another sample was collected later that day for four consecutive days using two different collection methods; i.e., the Colli-Pee® and a standard urine cup. Samples were collected at home and returned at ambient temperature to the laboratory by postal mail. HPV DNA testing was conducted with the Riatol qPCR HPV genotyping assay. Based on the combined generalized linear mixed model used, there was no significant impact of the timing of collection (morning versus later during the day) on copies of HPV DNA, whereas Colli-Pee® collected samples show higher HPV concentrations than cup collected samples. However, at high concentrations of hDNA, the benefit of the Colli-Pee® disappeared.

Human papillomavirus genotype and viral load agreement between paired first-void urine and clinician-collected cervical samples

The performance and acceptability of first-void urine as specimen for the detection of HPV DNA in a Belgian referral population was evaluated using an optimized sample collection and processing protocol. One hundred ten first-void urine and cervical samples were collected from 25- to 64-year-old women who were referred for colposcopy (January–November 2016). Paired samples were analyzed by the Riatol qPCR HPV genotyping assay. Acceptability data were gathered through questionnaires (NCT02714127). A higher high-risk HPV DNA prevalence was observed in first-void urine (n = 76/110) compared to cervical samples (n = 73/110), with HPV31 and HPV16/31 being most prevalent correspondingly. For both any and high-risk HPV DNA, good agreement was observed between paired samples (Cohen’s Kappa of 0.660 (95% CI: 0.486–0.833) and 0.688 (95% CI: 0.542–0.835), respectively). In addition, significant positive correlations in HPV copies (per microliter of DNA extract) between paired samples were observed for HPV16 (rs = 0.670; FDR (false discovery rate)-adjusted p = 0.006), HPV18 (rs = 0.893; FDR-adjusted p = 0.031), HPV31 (rs = 0.527; FDR-adjusted p = 0.031), HPV53 (rs = 0.691; FDR-adjusted p = 0.017), and HPV68 (rs = 0.569; FDR-adjusted p = 0.031). First-void urine sampling using a first-void urine collection device was preferred over a clinician-collected cervical sample. And mostly, first-void urine sampling at home was favored over collection at the clinic or the general practitioner’s office. First-void urine sampling is a highly preferred, non-invasive method that ensures good agreement in HPV DNA (copies) with reference cervical samples. It is particularly interesting as a screening technique to reach non-participants, and its clinical performance should be further evaluated.

First detection of papillomaviruses and polyomaviruses in swimming pool waters: unrecognized recreational water-related pathogens?

Viral outbreaks associated with swimming pools have been described worldwide. The objective of this study was to examine the extent of viral contamination in indoor and outdoor swimming pools. Pools were examined for the presence of human enteric viruses (adenovirus, norovirus and enterovirus) and nonenteric viruses (papillomavirus and polyomavirus-BK, JC, KI, WU and Merkel cell). Bacteriological parameters were also evaluated. The analysed pool waters met microbiological quality standards. Enteric viruses were not detected. On the other hand, papillomaviruses (HPV8, 12, 23, 25, 120 and unclassified HPVs) and polyomaviruses (JC and Merkel cell polyomaviruses) were detected in 9/14 samples (64%). The number of HPV DNA copies in pool waters, measured by quantitative Real-time PCR, ranged from 1.27E+04 to 1.13E+05/10L. Results show that a variety of nonenteric viruses may be discharged in pool waters by various secretions and excretions from infected individuals or asymptomatic carriers. To the best of our knowledge, this is the first report on human papillomaviruses and polyomaviruses in swimming pools. The likelihood that these viruses can be transmitted by recreational activities deserves to be explored in future studies.

Ultrasensitive, background‐free single copy DNA detection: Benchmarking performance using HPV infected cell lines and tissue biopsies

In situ hybridization (ISH), immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH) are common detection methods in biology. For high copy number targets, they perform well, but for single‐copy targets, sensitivity is often lacking. Chromosomal hybridizations require large probes (~100 kilobases) to obtain sufficient signal. At times, the desired target is not large enough for hybridization with probes of this size. We describe a method for single‐molecule detection wherein a probe contains multiple copies of a signaling moiety, like a fluorescent molecule, or an enzyme, like alkaline phosphatase, linked to a single binding molecule, like streptavidin. The small construct size allows efficient labeling of permeabilized cells. Cell lines and tissues infected with HPV, the disease‐causing agent of cervical cancer, were used to benchmark the method, employing biotinylated, probes specific to HPV subtypes. Using cell lines of known HPV DNA copy number, single copy detection per cell was demonstrated. The integrated copies of HPV16 in SiHa cells and chromosome spreads appear as punctate loci, as expected. Also, detection of the repressed p53 protein in HPV‐infected cells and tissue biopsies was demonstrated. The new method increases the overall sensitivity of FISH, ISH and IHC by roughly an order of magnitude and thus should prove applicable to the detection of cancer and infectious agents.

Interferon-Induced Gene Expression in Cervical Mucosa during Human Papillomavirus Infection

The aim of this study is to monitor type I interferon (IFN) activation in the cervical mucosa of Human Papillomavirus (HPV)-infected and uninfected women attending a routine gynaecologic clinic. The expression of three IFN-induced genes (MxA coding for human Mixovirus resistance protein A, ISG15 Interferon Stimulated Gene coding for a 15 kDa ubiquitin-like protein and UBP43 coding for the ISG15 isopeptidase) was determined as the mRNA copy number in cervical cells, normalized to the mRNA ones of the beta-glucuronidase gene. Type-specific HPV-DNA load was concurrently determined in the HPV-positive samples. Out of 127 samples tested, 54 were sufficient for both DNA and RNA extraction. The type-specific HPV-DNA copy numbers in the 34 HPV-positive samples varied widely. No significant association was found between copy numbers of MxA, ISG15, UBP43 and HPV status or viral load. However, despite a marked inter-individual variability, ISG15 expression was significantly higher when low-risk HPV infections were compared with HPV-negative samples, while high-risk HPV infections had very low ISG15 levels. The lack of ISG15 activation in high-risk HPV-infected cervical cells could be due to the lack of p53-mediated induction or to HPV-directed specific inhibition of type I IFN pathways. This study approach might be of value in clarifying the role of type I IFN activation in determining the clearance or persistence of HPV infections.

Prevalence of human papillomavirus 16/18/33 infection and p53 mutation in lung adenocarcinoma

Human papillomavirus (HPV) infection is a causative event for the development of uterine cervical carcinoma. Human papillomavirus (HPV) 16, 18, and 33 DNA has been also detected frequently in lung adenocarcinomas (AdCs) in East Asian countries; however, its prevalence in Japan remains unclear. We therefore screened for HPV 16/18/33 DNA in 297 lung AdCs in a Japanese population by multiplex PCR with type-specific primers. As reported previously, HPV 16 DNA was detected in two cervical cancer cell lines, CaSki and SiHa, while HPV 18 DNA was detected in HeLa cells, and 0.1-1.0 copies of HPV-DNA per cell were detectable by this method. However, with this method, none of the 297 lung AdCs showed positive signals for HPV 16/18/33 DNA, indicating that HPV-DNA is not or is very rarely integrated in lung AdC genomes in the Japanese. Furthermore, none of the lung AdCs showed positive signals by nested PCR with HPV 16/18 type-specific primers. Therefore, we further attempted to detect HPV 16/18/33 DNA in 91 lung cancer cell lines, including 40 AdC cell lines. Among them, 30 have been established in Japan and the remaining 61 in the USA. No HPV signals were obtained in any of the 91 cell lines by either multiplex or nested PCR, while the p53 gene was mutated in 81 of them including 35 of the 40 AdC cell lines. These results indicate that HPV 16/18/33 infection does not play a major role in the development of lung AdC in Japan nor in the USA.

High β-HPV DNA Loads and Strong Seroreactivity Are Present in Epidermodysplasia Verruciformis

Epidermodysplasia verruciformis (EV) is a rare disease, characterized by cutaneous warts and associated with a strong predisposition to beta-genus human papillomavirus (HPV). Earlier studies reported high copy numbers of HPV-DNA in nearly all skin tumors from EV patients, but neither HPV replication status in non-lesional skin nor anti-HPV seroreactivity in these patients have been reported yet. We therefore performed a comprehensive viral load analysis for the more common beta-HPV types on skin samples and plucked eyebrow hairs from four EV patients treated at our dermatology department. The results clearly demonstrate that they carry a multiplicity (up to eighteen types) of beta-HPV genotypes in both skin sites. Worthy of note, a high intrapatient concordance for specific types between hair bulbs and skin biopsies was observed and the same beta-PV profile was maintained over time. Viral load analysis revealed a load range between less than one HPV-DNA copy per 100 cells to more than 400 HPV-DNA copies per cell in both eyebrow hairs and skin proliferative lesions. Evaluation of seroreactivity to beta-HPV types in the four EV patients revealed that antibodies against the 16 beta-HPV were significantly more prevalent and showed higher titers than in the controls.

Type-specific human papillomavirus-DNA load in anal infection in HIV-positive men

To characterize anal human papillomavirus (HPV) infections in terms of genotype prevalence and type-specific DNA load in HIV-positive men. HIV-positive men attending the colo-proctological clinic of a University Hospital in Rome were recruited prospectively from November 2004 to July 2007. HIV-negative outpatients attending the same clinic over the same period were used as a control group. Anal brushings were tested for HPV-DNA using polymerase chain reactions and direct sequencing; type-specific HPV-DNA copies were measured in most positive samples. HPV data were correlated with patient HIV status and risk factors. HPV-DNA infection was detected in 81% of HIV-positive men. Almost all homosexual men were HPV-infected. The infection rate in low-risk HPV types was higher than in high-risk types. The spectrum of HPV genotypes was comparable between HIV-positive and HIV-negative men. Numbers of HPV-DNA copies varied greatly between samples but did not differ significantly between HIV-positive and HIV-negative men. In many samples, low-risk (HPV 6, 61, 70, and 74) viral loads were comparable with those of high-risk HPVs. Type-specific HPV-DNA copies at baseline appear to be independent of patient immune status and of HPV genotype. HPV genotype risk and viral load should be further evaluated for their potential predictive role in persistence and progression.

P16 expression in relation to human papillomavirus in liquid-based cervical smears

Objective At present, a simple and reliable cervical cancer screening test remains to be perfected. As overexpression of the protein p16 is correlated with the presence of high-risk HPV in malignant cervical lesions, this protein has been proposed as a surrogate marker of high-risk HPV infection in cervical cancer screening. Since high-risk viral DNA integration is necessary for neoplastic progression, we aimed to examine the expression of p16 in relation to the physical status of HPV (integrated or episomal) on liquid-based cervical smears. Methods For each of the 241 liquid-based cervical smear included in our study, we realized a Pap test. Residual cells were processed for in situ hybridization with mucosal HPV DNA probes and for immunocytochemistry with an anti-p16 antibody. Integrated or episomal copies of HPV DNA were detected as dotted or diffuse signals, respectively. Results In high-grade intraepithelial lesions, both the integrated form of high-risk HPV and overexpression of p16 were detected. However, we observed the presence of some p16-positive/HPV-negative normal and ASCUS smears. Moreover, some p16-negative ASCUS smears and low-grade intraepithelial lesions harbored episomal high-risk HPV. Conclusion If p16 was used as a surrogate marker of high-risk HPV infection, some women would be scored negative in spite of the presence of high-risk HPV. These women are more likely to undergo cancer progression, but no follow-up would be proposed to them in that screening pathway. A possible compromise for the triage of abnormal cervical smears should be a combination of both HPV and p16 testing.

Human Papillomaviruses Associated with Epidermodysplasia Verruciformis in Non-Melanoma Skin Cancers: Guilty or Innocent?

Abbreviations: AK, actinic keratoses; EV, epidermodysplasia verruciformis; HPV, human papillomavirus; ISH, in situ hybridization; NMSC, non-melanoma skin cancers; OTR, organ transplant recipients; SCC, squamous cell carcinomas; UVR, ultraviolet radiation

Human Papillomavirus-DNA Loads in Actinic Keratoses Exceed those in Non-Melanoma Skin Cancers

Recent studies suggest a role of cutaneous human papillomaviruses (HPV) in non-melanoma skin cancer (NMSC) development. In this study viral DNA loads of six frequent HPV types were determined by quantitative, type-specific real-time-PCR (Q-PCR) in actinic keratoses (AK, n=26), NMSC (n=31), perilesional tissue (n=22), and metastases of squamous cell carcinomas (SCC) (n=8) which were previously shown to be positive for HPV5, 8, 15, 20, 24, or 36. HPV-DNA loads in AK, (partially microdissected) NMSC, and perilesional skin ranged between one HPV-DNA copy per 0.02 and 14,200 cell equivalents (median: 1 HPV-DNA copy per 344 cell equivalents; n=48). In 32 of the 79 HPV-positive skin biopsies and in seven of the eight metastases viral loads were even below the detection limit of Q-PCR. Low viral loads in NMSC were confirmed by in situ-hybridization showing only a few HPV-DNA-positive nuclei per section. Viral loads in SCC, basal cell carcinomas, and perilesional tissue were similar. But, viral loads found in AK were significantly higher than in SCC (p=0.035). Our data suggest that persistence of HPV is not necessary for the maintenance of the malignant phenotype of individual NMSC cells. Although a passenger state cannot be excluded, the data are compatible with a carcinogenic role of HPV in early steps of tumor development.

HPV Episomal Copy Number Closely Correlates with Cell Size in Keratinocyte Monolayer Cultures

W12E keratinocytes maintaining episomal copies of HPV DNA were separated according to size by centrifugal elutriation. HPV DNA copy number was greatly increased in the largest, most differentiated cells of the population. The large cells with the highest HPV copy number also showed evidence of endoreduplication of host cell DNA. Other cell lines maintaining episomal copies of HPV18 and HPV31 were also tested with all lines showing similar results. The results demonstrate that increase in HPV DNA copy number correlates well with increased cell size, a fundamental marker of keratinocyte differentiation. The results also indicate that simple monolayer cultures may be useful for studying the relationship between differentiation, HPV DNA replication, and cell-cycle events.

Enhancer‐promoter Activity of Human Papillomavirus Type 16 Long Control Regions Isolated from Cell Lines SiHa and CaSki and Cervical Cancer Biopsies

Expression of human papillomavirus 16 (HPV‐16) oncogenes is markedly higher in cervical cancer cells than in precancerous cells, and the elevated expression is believed to be required for the malignant phenotypes. We compared cancer cell lines CaSki (with 200 to 400 copies of HPV‐16 DNA per cell) and SiHa (with one to two copies of HPV‐16 DNA per cell) for the E7 expression in cells and the enhancer‐promoter activity of the isolated viral long control region (LCR). Although these parameters per cell were 10‐fold higher in CaSki than in SiHa, the levels of the E7 mRNA and protein per HPV DNA copy were 10‐ to 20‐fold higher in SiHa than in CaSki. Characterization of the isolated LCRs showed that, whereas the LCR from CaSki resembled the prototype in structure and activity, the LCR from SiHa, with a deletion of 38 base pairs, enhanced transcription from P97 as assayed by using a plasmid capable of expressing luciferase. The upregulation appeared to be due to removal of one of the silencer YY1‐binding sites. Furthermore, we isolated and characterized LCRs from 51 cervical cancer patients’ biopsies. Among them, one with a deletion including YY1‐binding sites and the other with a substitution in a YY1‐motif were found to enhance the transcription. These findings suggest that mutation affecting YY1‐motifs in the LCR is one of the mechanisms enhancing the viral oncogene expression in the course of progression of cancer cells.

In situ hybridization detection of low copy nucleic acid sequences using catalyzed reporter deposition and its usefulness in clinical human papillomavirus typing.

In situ hybridization (ISH) detection of low copy DNA and RNA sequences using nonisotopic probes has been difficult in the past because of a lack of sensitivity. Several techniques, such as ISH with radioisotopic-labeled probes, in situ polymerase chain reaction, in situ reverse transcription polymerase chain reaction, self-sustained sequence replication, and chemiluminescence, have allowed increased sensitivity but have required specialized and often expensive equipment, lengthy protocols, and in the case of radioactive probes, there has been an associated increased health risk. Catalyzed reporter deposition (CARD) combined with ISH (CARD-ISH) increases the signal-generating potential of labeled hybridized probes and allows the detection of low copy sequences of nucleic acids in formalin-fixed, paraffin-embedded tissue sections. To determine the sensitivity of CARD-ISH to detect nucleic acids in routinely processed specimens, we analyzed the detection of HPV 16 and 18 infection in formalin-fixed, paraffin-embedded sections of cultured cell lines, including CaSki cells with 400-600 copies of HPV 16, HeLa 229 cells with 10-50 copies of HPV 18, and SiHa cells with 1-2 copies of HPV 16 using a conventional ISH method and by CARD-ISH. In addition, 20 cases of clinical specimens previously analyzed for HPV 6, 11, 16, 18, 31, 33, and 51 with the Enzo PathoGene kit (Enzo Diagnostics, Inc., Farmingdale, NY, U.S.A.) were reexamined with the CARD-ISH method. The CARD-ISH system detected one to two copies of HPV 16 in the SiHa cells whereas the conventional ISH method did not. Both methods detected HPV 16 and 18 in CaSki and HeLa 229 cells, respectively. Three clinical cases that were previously negative and two weakly positive cases of HPV infection were all strongly positive with the CARD-ISH system, a 25% increase in the detection of positive cases by CARD-ISH. We also showed for the first time that a cocktail of six biotinylated oligonucleotide probes was capable of detecting one to two copies of HPV 16 in SiHa cells. These results show that the CARD-ISH method increases the sensitivity of nonisotopic ISH to the level of detecting one to two copies of HPV DNA in formalin-fixed, paraffin-embedded tissue sections using biotinylated cDNA or oligonucleotide probes.

Specific inhibition of a human papillomavirus E2 trans-activator by intracellular delivery of its repressor.

Papillomaviruses are the causative agents of benign and malignant epithelial tumors of the skin and mucosa. They encode a DNA-binding protein, E2, that regulates viral transcription and replication, making it an important therapeutic target. By deleting the amino-terminal trans-activation domain of human papillomavirus type 16 (HPV-16) E2 while retaining its carboxy-terminal DNA binding and dimerization domain, an E2 repressor (E2R) that efficiently inhibits transcriptional activation by full-length HPV E2 was generated. To deliver this repressor protein into animal cells, we have utilized the human immunodeficiency virus type 1 (HIV-1) Tat protein which itself is taken up efficiently into intact cells. Chimeras of E2R and the cellular uptake domain of Tat specifically inhibited E2-dependent reporter gene expression in COS-7 cells. Treatment of cervical intraepithelial neoplasia cells having episomally replicating HPV-31 DNA with this Tat-E2R protein led to a dose-dependent loss of HPV DNA copies and inhibition of cell growth. Tat-mediated delivery can be a valuable tool for assessing protein function and may allow the development of novel therapeutic proteins having intracellular targets.

In situ hybridization 法による陰茎癌でのヒトパピローマウイルス (HPV) DNAの検討

The histochemical detection of human papillomavirus (HPV) was performed using the technique of in situ hybridization from the formalin fixed paraffin embedded specimens of penile carcinoma and condylomata+ acuminata . One of 19 penile cancer cases (5.3%) revealed the positive staining on the nuclei of the tumors for HPV type 16/18. However, the positive nuclei were scattered and localized in small part of the tumor which showed no koilocytosis. On the contrary, 11 of 12 condyloma acuminata cases (91.7%) showed positive staining on the nuclei of the tumors for HPV type 6/11, also 5 of the 11 cases (45.5%) revealed cross reaction for other type of HPV. The HPV types 6/11, 16/18 and 31/33/35 may be unrelated to the pathogenesis of the Japanese penile carcinoma. However, further study is necessary to evaluate that the number of HPV-DNA copy in our cases is too small, or the other type of HPV is responsibility.

Prevalence of HPV DNA and viral copy numbers in cervical scrapes from women with normal and abnormal cervices.

Cervical scrapes were obtained from 215 women with cytologically normal cervices and 74 women with cervical intraepithelial neoplasia (CIN) and probed for HPV 6, 11, 16, and 18 by dot-blot hybridization. Viral copy numbers were determined by densitometric scanning of autoradiographs. The prevalence of HPV DNA in women with normal smears was as follows: 23 per cent of women attending a Family Planning Clinic (FPC), 16 per cent of women attending a Sexually Transmitted Diseases (STD) clinic, and 48 per cent of women attending a laser follow-up clinic after treatment of CIN. Ten per cent of women with normal cervices harboured HPV 16. Viral copy numbers ranged from 1300 to 52,800 genome equivalents per cell. Twenty-seven HPV-positive women with normal smears (including four patients infected with HPV 16) were followed for up to 3 years. None developed CIN irrespective of copy number. Our results show that HPV is present in normal cervices in the absence of CIN. Copy number has no relation to the development of CIN and factors other than the amount of HPV DNA may trigger the neoplastic process.