Plurality of genital human papillomaviruses: characterization of two new types with distinct biological properties

Why HPV16? Why, now, HPV42? How the discovery of HPV42 in rare cancers provides an opportunity to challenge our understanding about the transition between health and disease for common members of the healthy microbiota

In 2022, a bioinformatic, agnostic approach identified HPV42 as causative agent of a rare cancer, later confirmed experimentally. This unexpected association offers an opportunity to reconsider our understanding about papillomavirus infections and cancers. We have expanded our knowledge about the diversity of papillomaviruses and the diseases they cause. Yet, we still lack answers to fundamental questions, such as what makes HPV16 different from the closely related HPV31 or HPV33; or why the very divergent HPV13 and HPV32 cause focal epithelial hyperplasia, while HPV6 or HPV42 do not, despite their evolutionary relatedness. Certain members of the healthy skin microbiota are associated to rare clinical conditions. We propose that a focus on cellular phenotypes, most often transient and influenced by intrinsic and extrinsic factors, may help understand the continuum between health and disease. A conceptual switch is required towards an interpretation of biology as a diversity of states connected by transition probabilities, rather than quasi-deterministic programs. Under this perspective, papillomaviruses may only trigger malignant transformation when specific viral genotypes interact with precise cellular states. Drawing on Canguilhem's concepts of normal and pathological, we suggest that understanding the transition between fluid cellular states can illuminate how commensal-like infections transition from benign to malignant.

Digital Papillary Adenocarcinoma in Nonacral Skin: Clinicopathologic and Genetic Characterization of 5 Cases

Digital papillary adenocarcinoma (DPA) is a rare sweat gland neoplasm that has exceptionally been reported outside acral locations. Recently, human papillomavirus 42 was identified as the main oncogenic driver of DPA. Herein, we report 5 tumors arising in extra-acral locations predominantly in the female anogenital skin. Four patients were female and 1 patient was male. The mean age at the diagnosis time was 65 years (range: 55 to 82 y). Tumors were located on the vulva (n=3), perianal area (n=1), and forearm (n=1). Histologically, all tumors were lobular and mainly solid and composed of sheets of cells with rare focal papillae and frequent glandular structures in a "back-to-back" pattern and lined by atypical basophilic cells. Immunohistochemistry showed diffuse positivity for SOX10. Epithelial membrane antigen and carcinoembryonic antigen highlighted the luminal cells and staining for p63 and p40 revealed a consistent and continuous myoepithelial component around glandular structures. Follow-up was available in 3 cases (mean duration: 12 mo [range: 8 to 16 mo]). One patient developed local recurrence and 1 experienced regional lymph node metastases. HPV Capture Next-generation sequencing revealed the presence of the HPV42 genome in all samples. Viral reads distributions were compatible in the 5 cases with an episomal nature of the viral genome, with a recurrent deletion in the E1 and/or E2 open reading frames. In conclusion, this study demonstrates that digital DPA may rarely present in nonacral locations mainly in the female anogenital area, usually with a more solid pattern as compared with those cases presenting on the digits and it is also associated with HPV42.

Human Papillomavirus (HPV) Cervical Lesions: Results from 300 Italian Women Studied with Dna Hybridization Techniques and Morphology

Human papillomavirus cervical infection was investigated in a series of 300 unselected women by comparing morphological diagnoses (cytology and histology) with results of DNA hybridization techniques (filter in situ hybridization of DNA from exfoliated cervical cells and Southern blot analysis of HPV-DNA in cervical biopsy specimens). The prevalence of HPV cervical infection diagnosed by PAP smears was 11.6 %. Despite disadvantages, filter in situ hybridization was confirmed to be particularly useful for screening purposes to detect HPV in cervical scrapings. In 3 cases it was the only applicable method for diagnosing « high-risk » HPV infection. Southern blot hybridization of tissue DNA with HPV 16-DNA revealed the presence of this virus in 8 cases, and HPV 31-DNA and HPV 42-DNA in 1 case each.

Histologic variation in high grade oral epithelial dysplasia when associated with high-risk human papillomavirus

OBJECTIVES

Reported cytologic alterations associated with high-risk human papillomavirus (HR-HPV) in oral epithelial dysplasia (HPV-OED) need further characterization.

STUDY DESIGN

Archival cases of high-grade oral epithelial dysplasia (hgOED) (N = 38) were assigned a cytologic score (CS) based on the average number of mitotic, karyorrhectic, and apoptotic cells per high-power field. Three groups were then generated on the basis of increasing CS: Focal (group 1, N = 14), Intermediate (group 2, N = 12), and Diffuse (group 3, N = 12). Polymerase chain reaction-based HPV genotyping and p16 immunohistochemistry were performed.

RESULTS

HR-HPV was found significantly more in group 3 (83.3%) compared with groups 1 and 2 (group 1&2; 42.9% and 41.7%, respectively; P = .047). HPV16 predominated in HR-HPV-positive cases (90.5%). By location, the tongue or the floor of mouth was associated with all groups (P = .04). Increasing CS was associated with a slightly younger age (P = .04) and increased expression of p16 (P = .005). CS and p16 expression were not sensitive but were highly specific predictors for HR-HPV presence. Based on limited follow-up information, HPV-OED does not differ in clinical aggressiveness compared with conventional OED.

CONCLUSIONS

Increased CS in hgOED is strongly associated with HR-HPV (mostly HPV16) and p16 expression. CS and p16 expression are specific predictors of HR-HPV presence. Further molecular study and long-term follow-up of HPV-OED are needed.

Human papillomavirus typing by single tube multiplex amplification in real time (SMART): the PapillomaFinder® SMART 20 assay

BACKGROUND

High-risk (hr) human papillomavirus (HPV) infections play a causal role in the development of cervical cancer. The detection of hrHPV is, therefore, advocated in cervical cancer screening programs.

OBJECTIVES

The aim of this study was to determine the performance of a novel HPV typing assay, PapillomaFinder® SMART 20. This is a one-tube-per-sample method, to be performed on standard real-time PCR platforms, using melting curve analysis to distinguish targets. The assay detects all 14 hrHPV types, of which 16, 18, 31, 33, 35, 39, 45, 52, 56 and 58 individually. HrHPV types 51, 59, 66 and 68 are detected in an hrHPV pool, and low-risk (lr) HPV types 6, 11, 40, 42, 43 and 44 in an lrHPV pool.

STUDY DESIGN

The method was tested on HPV plasmid models, WHO and QCMD proficiency panels and a series of clinical cytological samples (n=45), the latter in comparison with a clinically validated real-time quantitative PCR.

RESULTS

Type-specificity of the test was 100% using plasmids, the WHO and QCMD panels. Sensitivity for hrHPV in single infections was 100% using the WHO and QCMD panels and cytological samples, with an analytical sensitivity of 10-25 copies per reaction for all HPV types tested. Of the 34 HPV types present in the 8 multiple infections in the WHO panel, 30 were detected. In all cytological samples at least one hrHPV type was found, in concordance with the clinically validated method. Only when the viral load of the dominant HPV types in multiple infections greatly exceeded that of the other types in the infection, those other types were not always detected.

CONCLUSIONS

PapillomaFinder® SMART 20 is a rapid, easy to perform, single tube HPV typing assay. The assay detects the 14 hrHPV types, and the 6 most important lrHPV types with a high sensitivity and type-specificity.

Genomic diversity of low-risk human papillomavirus genotypes HPV 40, HPV 42, HPV 43, and HPV 44

In order to investigate the genomic diversity of low-risk human papillomavirus (HPV) genotypes, a total of 108 isolates of HPV 40, HPV 42, HPV 43, or HPV 44, obtained from anal swabs or tissue specimens of patients with anogenital warts, and cervical swabs of women with cervical intraepithelial neoplasia of different grades, were analyzed. The characterization of genomic variants was established by sequencing one third of the viral genome and analysis of three different genomic regions: L1, LCR, and E6. Maximum variant divergence accounted for 0.4-1.1% of the investigated genomic segments. Several novel, potentially important nucleotide substitutions, deletions, and insertions are described. Altogether, among 14 HPV 40 isolates, a total of nine different genomic variants were identified, composed of eight L1, five LCR, and four E6 genomic variants. Among 49 HPV 42 isolates, a total of 30 genomic variants were identified, composed of 20 L1, 18 LCR, and four E6 genomic variants. Among 10 HPV 43 isolates, distributed into two major genomic variant lineages with clearly defined nucleotide signatures, three genomic variants were identified, composed of three L1, two LCR, and two E6 genomic variants. Among 35 HPV 44 isolates, a total of eight HPV 44 and 11 subtype HPV 44 genomic variants were identified, composed of 13 L1, 14 LCR, and 6 E6 genomic variants. A similar level of genomic diversity of HPV 44 and its subtype was identified in our geographic region as has been reported previously on isolates collected worldwide.

Human papillomavirus genotype prevalence in cervical biopsies from women diagnosed with cervical intraepithelial neoplasia or cervical cancer in Melbourne, Australia

Multicenter international phase III clinical trials using multivalent human papillomavirus (HPV) vaccines for cervical cancer (CC) prevention are underway. As HPV immunity is type specific, defining HPV genotype prevalence in different regions to ascertain whether predominant types differ geographically is considerably important prior to vaccine implementation. This study aimed to define HPV genotypes present in CC and high-grade dysplasia among women in Melbourne, Australia. HPV genotype analysis of a cross section of women in Melbourne with cervical dysplasia/cancer was performed. A total of 493 cervical biopsies from patients being treated for moderate (n= 122) or severe (n= 180) cervical intraepithelial neoplasia (CIN II/III) or CC (n= 191) were tested for HPV genotypes using the PGMY09/11 primer system and line blot assay. HPV detection rates were 63.9%, 72.8%, and 86.9% in CIN II, CIN III, and CC biopsies, respectively. The most prevalent HPV genotypes among CC biopsies were HPV-16 (52.9%), HPV-18 (18.3%), HPV-45 (6.3%), HPV-39 (3.1%), and HPV-73 (2.6%). Multiple HPV infections, comprising two to five types, were identified in 14.4% of biopsies, being significantly fewer (5.2%) among CC biopsies (P < 0.0001). These results indicate that the two most prevalent CC-associated HPV genotypes in Australia parallel those described internationally, with type variations thereafter.

Detection of human papillomavirus type 56 DNA, belonging to a mucous high-risk group, in hair follicles in the genital area of a woman no longer suffering from viral warts

BACKGROUND

Human papillomaviruses (HPVs) parasitize human epithelium, but it is not clear where they reside when they do not cause apparent infection. Hair follicles are important candidates as reservoirs.

OBJECTIVES

A patient reported previously by us as having perianal warts caused mainly by HPV 56, demonstrated hair follicles in her genital area which bulged a little from the surface and appeared somewhat enlarged. We therefore examined whether DNA of HPV 56, a member of the mucous high-risk group, might be detectable in these structures.

METHODS

We obtained plucked hairs and performed an examination by polymerase chain reaction and subsequent reverse-phase dot blot hybridization (PCR-RDBH) and in situ hybridization (ISH).

RESULTS

Strong positive signals were obtained not only with PCR-RDBH but also with ISH.

CONCLUSIONS

Hair follicles in the genital area might serve as reservoirs for HPVs belonging to the mucous high-risk group.

Human papillomavirus genomes in squamous cell carcinomas of the uterine cervix

The association between invasive cervical carcinoma and human papillomavirus (HPV) has now been established beyond doubt, but this is not necessarily a direct-and-effect association. To assess the causality of HPV, we analyzed HPV genomes in squamous cell carcinomas (SCCs) [corrected] of the uterine cervix by both blot hybridization and PCR. Genital HPV sequences were found in 231 (79%) of 294 SCCs by blot hybridization with more than five copies of entire HPV genomes identified in some cases including HPV 16 (92 cases), HPV 58 (32 cases), and HPV 52 (24 cases). By PCR-direct sequence analysis in 250 of 294 SCCs, genital HPV sequences were found in 240 samples (96%). The partial L1 sequences of HPV 16 were identified in 123 cases, and those of HPVs 18 and 31 were found in 24 and 20 cases, respectively. In addition, multiple HPV types were identified in 29 (12%) of 250 SCCs, and the HPV copy number, detected by PCR only, was less than 0.05. Marked discrepancies were therefore evident between the two analytical techniques. In this report, we discuss the causality of HPV for SCC with regard to the length of the viral genome, the amount of viral DNA, and multiple HPVs in single SCCs.

Does the immune system see tumors as foreign or self?

Given the vast number of genetic and epigenetic changes associated with carcinogenesis, it is clear that tumors express many neoantigens. A central question in cancer immunology is whether recognition of tumor antigens by the immune system leads to activation (i.e., surveillance) or tolerance. Paradoxically, while strong evidence exists that specific immune surveillance systems operate at early stages of tumorigenesis, established tumors primarily induce immune tolerance. A unifying hypothesis posits that the fundamental processes of cancer progression, namely tissue invasion and metastasis, are inherently proinflammatory and thus activating for innate and adaptive antitumor immunity. To elude immune surveillance, tumors must develop mechanisms that block the elaboration and sensing of proinflammatory danger signals, thereby shifting the balance from activation to tolerance induction. Elucidation of these mechanisms provides new strategies for cancer immunotherapy.

Human papillomavirus and cervical cancer

Of the many types of human papillomavirus (HPV), more than 30 infect the genital tract. The association between certain oncogenic (high-risk) strains of HPV and cervical cancer is well established. Although HPV is essential to the transformation of cervical epithelial cells, it is not sufficient, and a variety of cofactors and molecular events influence whether cervical cancer will develop. Early detection and treatment of precancerous lesions can prevent progression to cervical cancer. Identification of precancerous lesions has been primarily by cytologic screening of cervical cells. Cellular abnormalities, however, may be missed or may not be sufficiently distinct, and a portion of patients with borderline or mildly dyskaryotic cytomorphology will have higher-grade disease identified by subsequent colposcopy and biopsy. Sensitive and specific molecular techniques that detect HPV DNA and distinguish high-risk HPV types from low-risk HPV types have been introduced as an adjunct to cytology. Earlier detection of high-risk HPV types may improve triage, treatment, and follow-up in infected patients. Currently, the clearest role for HPV DNA testing is to improve diagnostic accuracy and limit unnecessary colposcopy in patients with borderline or mildly abnormal cytologic test results.

Human papillomavirus immortalization and transformation functions

The high risk HPVs (such as HPV-16 and HPV-18) that are associated with specific anogenital cancers encode two oncoproteins E6 and E7, which are expressed in the HPV positive cancers. The E7 protein functions in cellular transformation, at least in part, through interactions with pRB and the other pRB related 'pocket proteins'. The major target of the E6 oncoprotein encoded by the genital tract, cancer associated human papillomaviruses is p53. Several lines of evidence suggest that E6 and E7 have additional targets important to the oncogenic potential of the virus. Work from a number of laboratories has focused on determining other activities of HPV relevant to carcinogenesis and identifying additional cellular targets of E6 and E7. This paper will review the state of the field at the time of the 19th International Papillomavirus Workshop in September 2001 with respect to the HPV encoded oncoproteins.

Human tumor growth is inhibited by a vaccinia virus carrying the E2 gene of bovine papillomavirus

BACKGROUND

Papillomavirus is the etiologic agent associated with cervical carcinoma. The papilloma E2 protein is able to regulate negatively the expression of E6 and E7 papilloma oncoproteins. Therefore, a new, highly attenuated vaccinia virus known as modified vaccinia virus Ankara (MVA), which carries the papillomavirus E2 gene, was used for the treatment of tumors associated with human papillomavirus.

METHODS

Analysis of expression of the E2 gene from the recombinant vaccinia virus was performed by reverse transcription-polymerase chain reaction of RNA isolated from infected cells. Detection of the E2 protein was done by immunoprecipitation from proteins labeled with [(35)S]-methionine, isolated from infected cells. The therapeutic effect of the MVA E2 recombinant virus over human tumors was tested in nude mice bearing tumors generated by inoculation of HeLa cells. Series of 10 nude mice with tumors of different sizes were injected with MVA, MVA E2, or phosphate-buffered saline. Tumor size was monitored every week to assess growth.

RESULTS

The MVA E2 recombinant virus efficiently expressed the E2 protein in BS-C-1 cells. This protein was able to repress, in vivo, the papillomavirus P105 promoter, which controls the expression of the E6 and E7 oncoproteins. In nude mice the MVA E2 virus reduced tumor growth very efficiently. In contrast, tumors continued to grow in mice treated with MVA or PBS. The life expectancy of MVA E2-treated mice was also increased three- to fourfold compared with that of animals that received MVA or PBS.

CONCLUSIONS

The growth of human tumors was efficiently inhibited by the MVA E2 recombinant vaccinia virus. The absence of side effects in treated animals suggested that the MVA E2 virus is a safe biologic agent that could in the future be used in humans for the treatment of cervical carcinoma.

Human papillomavirus-associated tumors of the skin and mucosa

This review discusses diseases of the lower genital tract in which the presence of human papillomavirus (HPV) DNA is well documented. We discuss epidemiologic, clinical, and experimental data supporting a causative role for HPV in mucosal malignancies, with emphasis on the role of viral and host factors in their pathogenesis. Of special interest is the recently discovered association of cutaneous tumors with HPVs, previously known only for tumors in epidermodysplasia verruciformis (EV). The frequent detection of EV-specific or EV-related HPVs in immunosuppressed persons and in cutaneous tumors in the general population supports the importance of EV as a model of cutaneous oncogenesis. We also discuss recent serologic findings based on enzyme-linked immunosorbent assay results with the use of viruslike particles. This is important both for detection of present or past HPV infection and for epidemiologic and immunologic studies. Novel therapeutic modalities for HPV tumors and prospects for prophylactic and therapeutic vaccination are presented.

Nonradioisotopic detection and typing of human papillomaviruses by use of polymerase chain reaction and single-strand conformation polymorphism

The polymerase chain reaction (PCR), used to detect human papillomavirus (HPV), is finding increasing applications in clinical laboratories. The standard method of analysis to detect amplified PCR products is ethidium bromide gel electrophoresis combined with labor intensive blot hybridization. In this study, we describe single-strand conformation polymorphism (SSCP) to detect and genotype simultaneously general primer GP5+/GP6+ amplified HPV DNA using semiautomated electrophoresis on polyacrylamide gels (PAGE) combined with sensitive silver staining. To establish a standard for the band patterns of the various HPV types, we used HPV plasmid DNA, which allowed us to distinguish HPV 6, 11, 16, 18, 31, 33, 35, 45, 51, 52, 56, and 58, covering the most frequently recognized types. All the types tested are separated from each other, demonstrating diverse band patterns, HPV 16 being the most distinct. We also investigated PCR-SSCP for HPV detection and typing of 86 cervical biopsies diagnosed as cervical intraepithelial neoplasia (CIN) I-III and known to be HPV positive by PCR-slot blot hybridization and in situ hybridization. The correlation with SSCP was 91% for in situ hybridization and 98% for PCR-slot blot hybridization. SSCP is reproducible and specific. Its sensitivity is comparable to slot-blot hybridization. The interval to SSCP is approximately 2 h after PCR compared with several days' work when using conventional blot hybridization. We concluded that SSCP may be more advantageous than other PCR-based typing technologies.

A novel genital human papillomavirus (HPV), HPV type 74, found in immunosuppressed patients

The genome of a novel human papillomavirus (HPV) type, HPV74, was cloned from an iatrogenically immunosuppressed woman with persisting low-grade vaginal intraepithelial neoplasia. HPV74 was found to be phylogenetically related to the low-risk HPV types 6, 11, 44, and 55. HPV74 or a variant of this type was found in specimens from three additional immunosuppressed women but not in about 3,000 anogenital specimens from immunocompetent patients.

Two novel genital human papillomavirus (HPV) types, HPV68 and HPV70, related to the potentially oncogenic HPV39

The genomes of two novel human papillomavirus (HPV) types, HPV68 and HPV70, were cloned from a low-grade cervical intraepithelial neoplasia and a vulvar papilloma, respectively, and partially sequenced. Both types are related to HPV39, a potentially oncogenic virus. HPV68 and HPV70 were also detected in genital intraepithelial neoplasia from three patients and one patient, respectively. Comparison with sequence data in the literature indicates that the subgenomic ME180-HPV DNA fragment, cloned from a carcinoma cell line, corresponds to an HPV68 subtype and that several HPV DNA fragments amplified by PCR from genital neoplasia represent worldwide distributed variants of HPV68 and HPV70.

Genital papillomavirus in Greek women with high-grade cervical intraepithelial neoplasia and cervical carcinoma

Fifty biopsies from high-grade squamous intraepithelial lesions (HG-SIL) and 14 cervical carcinoma biopsies from Greek women were screened for the presence of human papillomavirus (HPV) DNA sequences by Southern blot hybridization and by the polymerase chain reaction (PCR) for the presence of different HPV types. In high-grade SIL, HPV DNA sequences were detected in 44 of 50 biopsies with the following distribution: 36% HPV 16, 12% HPV 18, 6% HPV 31, 6% HPV 33, 4% HPV 51, and 24% unclassified HPV types. In cervical carcinoma biopsies, 13 of 14 specimens were positive for HPV DNA sequences. Six biopsies were positive for HPV 16, three were positive for HPV 18, and four contained unclassified HPV types. Overall, of the total 64 biopsies, 57 (89%) were positive for HPV DNA sequences. Of these, Southern blot hybridization alone detected HPV DNA sequences in 39 cases, whereas by PCR 18 additional specimens were found to be positive for HPV. Among the HPV 16-positive biopsies, two samples produced a Pstl banding pattern very similar but not identical to that of HPV 16 prototype and were referred to as HPV 16 isolates. One HPV 16 isolate appears to carry a mutation within the carboxy-terminal half of the L2 gene that results in the loss of a Pstl site. The other HPV 16 isolate had a similar Pstl banding pattern to that previously reported as HPV 16 "variant" found in Cape Town [Williamson et al., 1989, Journal of Medical Virology 28: 146-149, 1994, Journal of Medical Virology 43: 231-237.] and in Italy [Li Vigni et al., 1994, 2nd International Congress of Papillomavirus in Human Pathology (Abstracts), p 100.].

Risk of dysplasia in anal condyloma

BACKGROUND

Recent studies suggest an alarming incidence of dysplasia in homosexuals with anal condyloma. The purpose of our study was to determine the incidence of dysplasia in anal condyloma in our male patients and to determine risk factors for premalignant or malignant change.

METHODS

Between 1986 and 1994, 103 male patients were referred to our colorectal clinic for evaluation of anal condyloma. Ninety-one patients had biopsy for pathology and form the basis of this report. All charts were reviewed and results analyzed using the chi-squared test with the Yates correction factor.

RESULTS

Mean patient age was 31 +/- 11 years (range, 13 to 78 years) and mean duration of disease was 20 +/- 26 months (range, 2 to 120 months). There were 59 heterosexuals and 32 homosexuals/bisexuals. Two heterosexuals (3%) had invasive squamous cell carcinoma and four (6%) had dysplasia. One homosexual/bisexual (3%) had squamous cell carcinoma in situ and nine (28%) had dysplasia (p < 0.05). Statistical analysis revealed that HIV seropositive status and disease location above the dentate line also predicted increased risk of dysplasia, whereas duration of disease, previous topical therapy, substance abuse, and other sexually transmitted diseases were not significant risk factors.

CONCLUSIONS

Homosexual orientation, disease above the dentate line and HIV seropositivity increase the risk of dysplasia in perianal condyloma. The incidence of dysplasia in perianal condyloma is significant enough to warrant consideration of biopsy in all patients.

Typing of human papillomaviruses in condylomata acuminata from Greece

DNA samples from recurrent condylomata acuminata biopsies of Greek males and females were examined for the presence of human papillomavirus (HPV) DNA using high-stringency Southern blot hybridization analysis. Of the twenty-six biopsies, 25 were positive for the HPV 6/11-related DNA sequences, and when further analyzed with the polymerase chain reaction (PCR) the HPV-negative biopsy was also positive for HPV 6/11 DNA. Nineteen specimens were further characterized based on their Pstl restriction endonuclease hybridization pattern. Twelve biopsies were positive for HPV 6a, one biopsy was positive for HPV 11a, and one biopsy was positive for HPV 6c DNA. Three specimens contained HPV 6/11 related DNA that gave an unusual Pstl pattern, and one specimen appeared to represent a multiple HPV infection containing HPV 6/11- and HPV 31/35/39-related sequences. Finally, one sample contained a mixture of HPV 6a DNA and an HPV 6a-like genome. Biopsies were also taken from adjacent apparently normal tissue, 0.5 cm away from the lesion, in 19 of the patients. Only one of these was found to be positive for HPV 6a DNA by Southern blot analysis.

Human papillomavirus infection in Norwegian women with cervical cancer

The objective of the present study was to determine the prevalence of human papillomavirus (HPV) infections in Norwegian women with cervical cancer. We used the polymerase chain reaction (PCR) and Southern blot techniques to assess the prevalence of HPV in cervical biopsies of 133 women admitted to the Norwegian Radium Hospital for treatment of cervical cancer. At the time of sampling (from February 1988 to April 1989) about 85% of Norwegian women with cervical cancer were treated at the Norwegian Radium Hospital. HPV was found in biopsies of 91 (68%) of women with cancer; 70 (53%) biopsies contained HPV type 16, 19 (14%) HPV type 18, 4 (3%) HPV type 33, 2 (1.5%) HPV type 11, and 3 (2%) HPV DNA of unknown type (HPVX). Five percent of biopsies were doubly infected, chiefly with HPV 16 + 18. We found a significant association between HPV 18 and low age, poorly differentiated tumors and adenocarcinomas. Our results show that there is an association between HPV types 16 and 18 and cervical cancer also in a Norwegian setting. PCR was more sensitive than Southern blotting for detection of HPV. Thirty-six (27.5%) of cancer biopsies were positive by PCR but negative by Southern blotting, as against 49 (73.5%) positive by both methods; we also encountered 4 samples positive by Southern blotting and negative by PCR. In 23/53 cancer biopsies positive by Southern blotting we found evidence for integrated or rearranged HPV genomes.

Prevalence of HPV in a Melbourne female STD population: comparison of RNA and DNA probes in detecting HPV by dot blot hybridization

A total of 377 women, consecutively selected as first attenders to a sexually transmitted diseases clinic in Melbourne, Australia, were examined for overt Condylomata acuminata and were screened for genital HPV DNA types 6, 11, 16, 18, 31, 33 and (35) using 2 dot blot hybridization methods. Overall, there was a 90% positivity correlation between the 2 methods with HPV DNA being detected in 12% of ectocervical samples. Overt warts were found in 15% of the women and HPV DNA was detected at the cervix in 35% with cytology predicting HPV with or without dysplasia in 27%. Thirteen percent had a past history of warts but none on examination and HPV DNA was evident in 16% while 18% had cytological features of HPV. Those with no warts evident and no past history of warts had both HPV DNA and cytological features of HPV in 7%.

High-risk genital papillomaviruses and degree of dysplastic changes in the cervix: a prospective study by fast multiplex polymerase chain reaction in Belgium

The epidemiologic studies with the least selection bias do not support the hypothesis that HPV types 16 and/or 18 are strongly associated with cervical cancer. In this preliminary report, we describe our findings regarding type 16, 18, and 33 detection rates in 323 normal and 71 dysplastic or neoplastic cervical scrapes using fast multiplex PCR. This modified PCR technique has been shown to be the most sensitive, specific, and reproducible DNA detection method for large epidemiologic studies. The results indicate a high relative risk of increasingly severe cervical abnormality associated with the presence of high-risk HPV DNA. The analysis of the prevalence and age data according to CIN status by non-parametric statistic tests highlights the importance of other factors inversely correlated with age in the cervical transformation process.

Detection of human papillomavirus DNA and mRNA using synthetic, type-specific oligonucleotide probes

Type-specific 30'mer-36'mer oligonucleotide probes complementary to mRNA transcribed from the E6 and E7 open reading frames of HPV 6b/11, 16, 18 and 33 were designed using the published nucleotide sequences. As oligonucleotides are easily and relatively cheaply synthesized in large amounts and are free of vector DNA, they were assessed for potential use in routine clinical detection and typing of HPV. Multiple Southern and dot blots of cloned HPV 6b, 11, 16, 18, 31 and 33 DNA, and of DNA extracted from cell lines carrying integrated HPV 16 and 18 genomes were prepared. In addition, Northern and dot blots of RNA extracted from the HPV-containing cell lines HeLa, CaSki and SiHa, were also prepared. All filters were first probed with the oligonucleotide and then with the corresponding full-genomic HPV DNA probe and their relative sensitivities and specificities compared: both probe types were labelled with 32P. The oligonucleotide probes were all as specific as the full-genomic probes for Southern, DNA and RNA dot blot hybridisations. The HPV 16 and 18 oligonucleotide probes detected HPV transcripts of the appropriate sizes in the cell line RNA. For DNA detection, oligonucleotide probes were up to 10 times less sensitive than the full-genomic probes, but for RNA detection, they were more sensitive. The sensitivity for both HPV DNA and RNA detection could be improved by using two type-specific oligonucleotide probes in combination, without reducing the specificity. The ease of preparation and handling of oligonucleotide probes, together with their lack of contaminating vector DNA, suggests that they may have some advantages over full-genomic probes for the clinical detection and typing of HPV.

Human papillomaviruses associated with cervical intraepithelial neoplasia. Great diversity and distinct distribution in low- and high-grade lesions

All together, 30 genital human papillomavirus (HPV) types have been characterized so far. To evaluate the importance of HPV diversity in associated cervical diseases, we analyzed 188 biopsy specimens obtained from patients with a recent diagnosis of cervical HPV infection or intraepithelial neoplasia (CIN). Of these 188 specimens, 116 were classified as low-grade CIN (48 cases), high-grade CIN (53 cases), condylomata acuminata (10 cases), flat condylomas (five cases). Seventy-two specimens were considered nondiagnostic. Using probes specific for 18 genital HPV types, HPV DNA sequences were detected by Southern blot hybridization in 100 lesions and 21 nondiagnostic specimens. When further analyzed by the polymerase chain reaction, eight HPV-negative biopsy specimens, four CIN, and four nondiagnostic specimens were positive. Of the 129 positive biopsy specimens, 92 contained at least one of 18 known HPV types and 37 HPV that have not yet been identified. Nine specimens had more than one type. Thirteen HPV types were identified in CIN. The detection rate of HPV 16 increased from 21% in low-grade CIN to 57% in high-grade CIN. HPV 18 was detected in only 3% of CIN; HPV 31, 33, and 35 were found in 8%. HPV 30, 39, 45, 51, 52, 56, 58, and 61 were detected in 44% of low-grade CIN but in only 8% of high-grade CIN. Unidentified HPV were detected in about 25% of low-grade and high-grade CIN. Fifty-seven CIN positive for at least one HPV type were further analyzed by in situ hybridization. Thirty-five (65%) biopsy specimens were positive, including 21 of 24 low-grade CIN and 14 of 33 high-grade CIN. Ten of the 13 previously identified HPV types were detected. Thus, CIN represents an heterogeneous disease from a virologic viewpoint. This fact could explain their variable clinical evolution.

General primer polymerase chain reaction in combination with sequence analysis for identification of potentially novel human papillomavirus genotypes in cervical lesions

We recently described the detection of potentially novel human papillomaviruses (HPV) genotypes (HPV types X [HPV X]) in cervical smears (A. J. C. van den Brule, C. J. L. M. Meijer, V. Bakels, P. Kenemans, and J. M. M. Walboomers, J. Clin. Microbiol. 28:2739-2743, 1990) by using the general primer-mediated polymerase chain reaction method (GP-PCR). In this study, the HPV specificities of GP-PCR products were determined by sequence analyses. M13 bacteriophage clones of PCR products derived from cloned unsequenced HPV genotypes 13, 32, 35, 43, 44, 45, 51, and 56 were subjected to dideoxy sequencing. Analyses of the putative amino acid sequences of these HPV types in addition to published HPV sequence data revealed stretches of highly conserved amino acid residues present in all HPV types, resulting in an HPV amino acid consensus sequence. Subsequently, HPV X-specific PCR products found in premalignant cervical lesions (n = 3), carcinomas in situ (n = 6), and invasive cancer (n = 6) were analyzed for their nucleotide sequences. Comparison of these sequences with published HPV nucleotide sequences and data obtained in this study revealed three HPV type 35, two HPV type 45, one HPV type 51, two HPV type 56, and six unique HPV X sequences, of which three types were present in four cases of carcinomas (in situ). The nucleotide sequences determined appeared to be unique after a data bank search. Furthermore, the sequences of all HPV X isolates matched the HPV amino acid consensus sequence, thus confirming HPV specificity. This study illustrates the power of GP-PCR in combination with sequence analysis to determine HPV specificity and genotyping of PCR products derived from sequenced as well as unsequenced HPVs, including novel, not yet identified HPV types.

Human papillomavirus (HPV) DNA in penile carcinomas and in two cell lines from high-incidence areas for genital cancers in Africa

Biopsies of 13 penile cancers (PC), from patients living in regions of Uganda with a high incidence of genital cancers, were studied for the presence, molecular characteristics and physical state of DNA related to that of human papillomavirus (HPV) types 6, 11, 16, 18, 31 and 33. HPV DNA sequences were detected in all PC specimens by dot/Southern blot analyses and by gene amplification of DNA sequences highly conserved among several HPVs. HPV 16 DNA sequences were found in one PC; DNA sequences with low homology to HPV16 or HPV18 were present in all other samples. Viral DNA is primarily integrated in the cellular DNA. To isolate and characterize a possible highly oncogenic HPV, a genomic library of the DNA extracted from the PC-8 biopsy has been constructed in the EcoRI arms of the EMBL4 phage. A single phage containing 8.30-kb HPV16-related sequences has been identified and the 3 segments of 0.45, 0.65 and 7.2 kb, released by EcoRI digestion, have been independently subcloned in pUC18 for further analysis.

The acetic acid test in evaluation of subclinical genital papillomavirus infection: a comparative study on penoscopy, histopathology, virology and scanning electron microscopy findings

OBJECTIVES

To evaluate colposcopic criteria in acetowhite lesions of the penis ("penoscopy") for the diagnosis of subclinical genitoanal papillomavirus infection (GPVI) compared with histopathological criteria of HPV involvement and to various hybridisation assays for HPV DNA detection, and to depict typical lesions by scanning electron microscopy.

DESIGN

The study included 101 randomly selected male partners of females with known GPVI, or with penile symptoms such as itching, burning and dyspareunia who did not exhibit overt genital warts but appeared to be afflicted with acetowhite penile lesions after topical application of 5% acqueous acetic acid. Lesions were judged by penoscopy as either typical, conspicuous or nontypical for underlying HPV infection. Biopsy specimens from 91 men were examined by light microscopy and by either Southern blot (SB), polymerase chain reaction (PCR) and/or in situ hybridisation (ISH) assays for the presence of HPV DNA of the HPV types 6, 11, 16, 18, 31, 33 and 42 (Group A). From another ten men lesions clinically typical for GPVI were also examined topographically by scanning electronic microscopy (Group B).

SETTING

The STD out-patient clinic of the Department of Dermatovenereology of Karolinska Hospital, Stockholm, Sweden.

RESULTS

Group A Seventy eight (86%) of the biopsied lesions met the penoscopy criteria of being either typical of or conspicuous for GVPI. The agreement between penoscopy and histopathology was fairly good, as HPV diagnosis was made by both methods in 56 (62%) of the cases. The reliability of applying strict colposcopic hallmarks was further substantiated by the finding that 55 (60%) of the biopsy specimens taken from penoscopically typical/conspicuous lesions contained HPV DNA. However, there are diagnostic pitfalls for the acetic acid test. Coexistence of an eczematoid reaction with changes indicative of HPV influence was detected in six (7%) of the cases, while an inflammatory response only occurred in 17 (19%) of the specimens. Additional histopathological diagnoses (normal epithelium, lichen sclerosus et atrophicus, balanitis circinata parakeratotica, verruca plana) were established in another eight (9%) of the cases. Among the HPV DNA positive cases, all of the HPV types tested for were detected with the exception of HPV 18. A severe penile intraepithelial neoplasia (PIN III) was revealed in five (5%) of biopsies; HPV 16 was present in two and HPV 42 in one of these biopsy specimens.

GROUP B

Scanning electron microscopy depiction harmonised with the penoscopy findings showing that subclinical GPVI characteristically exhibits a well demarcated, slightly elevated border and that the central area of lesions often displays a "groove" in which the epithelium appears to be thin with protrusions from beneath that probably represent capillaries.

CONCLUSION

Use of the acetic acid test for evaluation of GPVI should be combined with a colposcopic evaluation based on strict topographic hallmarks, followed by a directed biopsy for light microscopic evaluation. We found that the positive predictive value of colposcopy was as high when correlated with histopathological findings (72%) as when virological methods were used, whether HPV DNA hybridisation testing was performed with the well established SB and ISH assays (45%), or by applying the newly introduced and highly sensitive PCR assay as well (71%). False positivity from the acetic acid test occurs and is mainly due to inflammatory conditions but also to the presence of other conditions. Epithelial fissures are evidently associated with some subclinical GPVI lesions and may potentially represent loci minores for infectious stimuli and perhaps facilitate the transmission of some blood-borne STDs. We prose that the term "papillomavirus balanoposthitis" should be used for penile HPV infection associated with inflammatory responses. Our study indicates that PIN III frequently occurs in a subclinical form and may be associated with not only previously identified "high-risk" HPV types such as type 16, but also with the HPV type 42 that has not previously been considered as oncogenic.

Short sequence in L1 region of human papillomaviruses correlates with clinical pictures and grouping by cross-hybridization

A consensus primer-mediated polymerase chain reaction devised to amplify a short sequence in L1 region (L1-PCR) efficiently detected genital human papillomaviruses (HPVs) in clinical materials. Nucleotide sequencing of the amplified fragment showed that L1-PCR is also applicable to hitherto unsequenced HPVs. By comparing the amplified 210 nucleotides HPVs were classified into six groups, which are consistent with clinical pictures and a grouping based on cross-hybridization under the stringent condition.

Prevalence of high risk genital papillomaviruses in the Belgian female population determined by fast multiplex polymerase chain reaction

Because in situ/filter hybridisation is not sensitive enough and because classical polymerase chain reaction (PCR) protocols are generally not sufficiently reproducible and specific, there is little accurate information on the prevalence of human papillomaviruses (HPV) 16, 18, and 33 infections in women without dyskaryotic changes of the cervix. In our hands, our Fast Multiplex PCR protocol has always been the most sensitive, specific, and reproducible DNA detection assay in all the microbiological and haematological applications we attempted (Vandenvelde C, Verstraete M, Van Beers D [1990]: Journal of Virological Methods 30:215-228; Vandenvelde C, Scheen R, Corazza F, Van Beers D [1991a]: Journal of Experimental and Clinical Hematology 33:293-297; Vandenvelde C, Scheen R, Van Beers D, Fondu P [1991b]: Journal of Experimental and Clinical Hematology 30:25-29). Using this new technique, cervical scrapes from 336 Belgian women attending the cervical cancer screening clinic were examined for the presence of these three high-risk genital papillomaviruses. Positive results were confirmed using another set of HPV-specific primers. Exactly one sixth of our population was found positive for one or more of these HPVs. Types 33 and 16 were significantly more prevalent than type 18. The nonparametric statistical analysis of the data suggests that some risk factors such as particular sexual habits, that are inversely related to age, must exist.

Molecular and biological characterization of cottontail rabbit papillomavirus variant DNA sequences integrated in the VX7 carcinoma

The transplantable VX7 carcinoma was derived from a tumor induced by a recoverable strain of cottontail rabbit papillomavirus (CRPV) able to replicate in domestic rabbits. Low levels of late viral gene expression have been retained through serial propagation in rabbits. We have cloned and characterized the three major types of CRPV sequences integrated in this tumor, a genome-length 8-kb DNA molecule and two rearranged 9- and 3.8-kb molecules. The VX7 8-kb DNA displays only a few differences in its restriction map, when compared to the wild-type (wt) CRPV DNA. The VX7 9- and 3.8-kb DNAs derive from the VX7 8-kb DNA since they share the same restriction site polymorphism. The VX7 9-kb DNA contains a duplication of the E6 open reading frame. The VX7 3.8-kb DNA results from the deletion of most of the E region and the insertion, between the borders of the deletion, of 174-nucleotide-long segment of the long control region potentially driving the expression of a truncated L2 protein. Both VX7 9- and 3.8-kb species potentially allow the expression of abnormal E6 fusion proteins. Nineteen point mutations were detected in the 3.8-kb DNA, compared to the wt CRPV DNA. None of these molecules were able to induce warts in domestic rabbits, in contrast to wt CRPV DNA. Furthermore, when cloned VX7 DNAs were inoculated together with wt CRPV DNA, none of the VX7 CRPV sequences, as identifiable by their specific restriction enzyme cleavage patterns, could be detected in the resulting warts. This suggests that CRPV sequences integrated in the VX7 carcinoma are no longer able to replicate as episomes, which might be a prerequisite for the production of warts.

Human papillomavirus type 42: new sequences, conserved genome organization

We report the nucleotide sequence and genome organization of the human papillomavirus type 42. HPV42 DNA was isolated from vulvar papillomas. It has been detected in benign forms of proliferative lesions only. The genome of HPV42 is 7917 bp long and shows the open reading frame pattern conserved in all HPVs sequenced so far. HPV42 has no high degree of sequence homology to any of the known HPVs. It shows characteristics previously found either exclusively in HPVs associated with invasive carcinomas or exclusively in nongenital HPVs. Therefore it cannot be readily ascribed to any of the established subgroups of human papillomaviruses.

Characterization of human papillomavirus type 66 from an invasive carcinoma of the uterine cervix

Human papillomavirus (HPV) DNA sequences coexisting with HPV16 and HPV45 were cloned from an invasive cervical carcinoma. The cloned HPV was shown to be a novel type, named HPV66, and is related to HPV56 (an HPV detected in cervical cancer). After screening 160 anogenital biopsies, four specimens exhibited histological features of intraepithelial neoplasia and contained HPV66 sequences. Of these, three were found to be associated with another HPV type.

Genetic heterogeneity among human papillomaviruses (HPV) associated with epidermodysplasia verruciformis: evidence for multiple allelic forms of HPV5 and HPV8 E6 genes

In order to get some insight into modifications of human papillomavirus (HPV) genomes which could play a role in tumor progression in epidermodysplasia verruciformis (EV), we studied three EV patients infected by HPV5 and one by HPV8, with cancers containing mostly or only episomal viral genomes with a deletion. The mutants were compared with the full-length genomes present in the benign lesions of each patient. Deletions affected the L1 and/or L2 open reading frames (ORFs), and extended in the 5' end of the long control region in two cancers. The isolates studied showed a polymorphism of restriction endonuclease cleavage sites and variations in the nucleotide sequence of the E6 ORF and the regions flanking the deletions. However, except for one patient infected by two distinct HPV5 variants, no difference was observed in the nucleotide sequence of isolates cloned from the benign lesions and the cancer of the same patient. This may suggest that point mutations are not involved in tumor progression. Comparison of nucleotide sequence data revealed an unexpectedly high number of nucleotide substitutions among the four HPV5 variants and the HPV8 variant, as compared with HPV5 and HPV8 published sequences. Changes involved 49 of the 457 nucleotides of HPV5 E6 ORF and 14 of the 465 nucleotides of HPV8 E6 ORF. This corresponds to amino acid substitutions affecting 17 of the 157 amino acids of HPV5 E6 proteins and 7 of the 155 amino acids of HPV8 E6 proteins. Half of the substitutions represent nonconservative changes. The variants showing the highest degree of sequence variation were detected in additional EV patients by PCR. This points to the existence of a set of HPV5 and HPV8 stable variants, encoding for multiple allelic forms of the transforming E6 gene.

Detection of genital papillomavirus types by polymerase chain reaction using common primers

We describe the detection of eight genital human papillomavirus (HPV) types, including HPV16 and HPV18, by PCR amplification of a 323 base-pair region of the genome within the L1 open reading frame (ORF). The primer sequences are: TGYAAATATCCWGATTWTWT and GTATCWACMACAGTAACAAA. The method will detect purified HPV16 DNA down to a concentration of as little as a single molecule in 100 microliters. The method is also applicable to purified DNA and crude lysates from tumour biopsies. Typing of the PCR product can be achieved with specific oligonucleotide probes.

Viral transcription in human keratinocyte cell lines immortalized by human papillomavirus type-16

Human papillomavirus type-16 (HPV-16) transcription in two human keratinocyte cell lines (HPK) immortalized by transfection of viral DNA in vitro was analyzed by nucleotide sequencing of cDNA clones, and in addition by primer extension analysis and S1 nuclease and exonuclease VII digestion of poly(A)+ RNA. A novel mRNA species which probably initiates in the E7 ORF and in which the 5'-part of the E1 ORF (splice donor at position (pos.) 880) is joined to an exon comprising the entire E2 ORF (splice acceptor at pos. 2708) was found in both cell lines. This mRNA has the potential to encode a full-length E2 protein, which is known to function as a repressor of transcription initiated at P97. cDNAs derived from the late region of the viral genome and the use of a late polyadenylation signal at pos. 7320-7325 are described. In agreement with RNA data published by others the major promoter for HPV-16 transcription is located at pos. 97. mRNA species encoding full-length or truncated forms of the E6 protein, and species characterized by an E1i [symbol see text] E4 splice junction (which provided the E4 open reading frame (ORF) with an ATG triplet) were identified.

Prevalence of different types of human papillomavirus in cervical infection of north Italian women

We investigated the prevalences of human papillomavirus (HPV) of type 6, 11, 16, 18, 31, 33, 35 and 42 in 276 cervical tissue samples biopsied from a group of North-Italian women in which a HPV infection of the cervix had been suspected. The specimens were evaluated by conventional histological examination and by HPV typing, using Southern blot hybridization on the extracted DNA. We related different degrees of squamous cervical dysplasia, showing or not viral cytopathic effects, with the HPV types harboured in the lesions. Significant rising of HPV 16 prevalences was observed proceeding from mild to moderate and to severe dysplasias both in presence (r = 0.9623, P less than 0.01) and in absence (r = 0.879, P less than 0.05) of koilocytosis, while an opposite trend was detected for HPV 6 and 11. In our sampling we did not find HPV 35 DNA sequences; in all occasions HPV 31 was associated with mild dysplasias. The absolute prevalences of types 18, 33 and 42 were generally low (from 2 to 3%); they did not show any association with specific histological damage of the cervix or with significant patterns related with the progression of cervical dysplasia.

Human papillomavirus in exophytic condylomatous lesions on different female genital regions

Clinically diagnosed exophytic condylomatous lesions on the vulva (20 cases), vagina (5 cases), and cervix (9 cases) were examined pathologically, and human papillomavirus (HPV) types present in those lesions were identified by Southern blot hybridization analysis. All vulvar and vaginal lesions showed typical histopathological features of classical condylomata, and HPV 6 and 11 were found in 15 vulvar and 3 vaginal lesions and in 5 vulvar and 2 vaginal lesions, respectively. In 5 cervical lesions with typical condylomatous changes, HPV 6 or 11 was also detected; however, HPV 16 was found in 2 cases of cervical lesion surrounded by prominent intraepithelial neoplasia, and HPV 31 was found in 2 cases of slightly elevated lesion with intraepithelial neoplasia. These observations suggest that HPV 6 and 11 have the potency to induce the specific pathological changes, condylomatous, in any regions of the female lower genital tract.

Detection and typing of multiple genital human papillomaviruses by DNA amplification with consensus primers

Many types of human papillomavirus (HPV) are associated with genital lesions. In order to develop simple and sensitive diagnostic procedures for HPV infection, we took advantage of the polymerase chain reaction (PCR). We compared the published nucleotide sequences of the L1 region from six genital HPV types and designed a pair of consensus primers for L1 region. The PCR with the consensus primers for L1 region (L1-PCR) could amplify at least nine genital HPV types, 6, 11, 16, 18, 31, 33, 42, 52 and 58, and the amplified HPV DNA could be typed by subsequent restriction mapping. L1-PCR was compared to Southern blot analysis and also to the consensus primer-mediated PCR for E6 region (E6-PCR) described before. Although both our PCR systems are nonradioactive, PCR for E6 region (E6-PCR) described before. Although both our PCR systems are nonradioactive, the sensitivity in detecting HPV DNA was even better than that obtained by using Southern blot analysis. By means of the PCR systems we detected HPV DNA in 100% of cervical condylomas (10/10), 92% of cervical intraepithelial neoplasias (33/36) and 96% of invasive cervical carcinomas (53/55), while we detected HPV DNA in 12% of normal cervices (12/102).

Genome organization and nucleotide sequence of human papillomavirus type 39

The 7833-bp nucleotide sequence of human papillomavirus type 39 (HPV39), which is associated with genital intraepithelial neoplasias and invasive carcinomas, has been determined. The genome organization deduced from the sequence shares characteristic features with other genital papillomaviruses. According to sequence comparisons, HPV39 most closely resembles HPV18 and may be a member of a subgroup of genital papillomaviruses distinct from the HPV16/31/33 group. As a novel feature, we report a 1.3-kb open reading frame on the DNA strand which lacks major open reading frames in the other sequenced HPV genomes.

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.