Isolation of a human papillomavirus from a patient with epidermodysplasia verruciformis: presence of related viral DNA genomes in human urogenital tumors

Papillomaviruses in the causation of human cancers - a brief historical account

Approximately 35 years ago a role of human papillomaviruses (HPV) in cervical cancer has been postulated. Today it is well established that this very heterogeneous virus family harbours important human carcinogens, causing not only the vast majority of cervical, but also a substantial proportion of other anogenital and head and neck cancers. In addition, specific types have been linked to certain cutaneous cancers. In females, HPV infections on a global scale account for more than 50% of infection-linked cancers, in males for barely 5%. Vaccines against the high risk HPV types 16 and 18 represent the first preventive vaccines directly developed to protect against a major human cancer (cervical carcinoma). This review will cover some of the historical aspects of papillomavirus research; it tries briefly to analyze the present state of linking HPV to human cancers and will discuss some emerging developments.

Methods for diagnosing papillomavirus infection

The morphology of the lesion and the site in which the lesion is found are the initial clues in classifying papillomavirus-induced neoplasia. Human papillomavirus (HPV) types have limited site-specificity and differ in their association with benign or malignant neoplastic development. Cytopathology, electron microscopy, antigen detection and molecular hybridization all play a role in the armamentarium of diagnostic methods. Although nitrocellulose blotting procedures provide the most accurate and sensitive method for detecting and characterizing viral nucleic acid sequences, recent improvements in cytological hybridization methods allow for rapid detection of virus and analysis of HPV type directly in biopsied tissue and in cervical smears. In particular, these in situ hybridization procedures facilitate retrospective studies of stored specimens.

Epidermodysplasia verruciformis: a model for understanding the oncogenicity of human papillomaviruses

The first evidence for the oncogenic potential of human papillomaviruses (HPVs) was obtained through the study of epidermodysplasia verruciformis (EV). This rare skin disease is characterized by disseminated, refractor, pityriasis versicolor-like lesions as well as flat wart-like lesions, and by the development of skin carcinomas in about 30% of the patients. EV is a multifactorial disease involving genetic, immunological and extrinsic (actinic) factors, in addition to infection with specific HPV types. A number of HPVs (at least 15 types) have been characterized in benign EV lesions. HPV DNA sequences are regularly detected in EV carcinomas but, in contrast to benign lesions, the types associated with cancers are usually restricted to HPV-5 and, less frequently, HPV-8, an HPV-5-related type. HPV-5 genomes are usually found as free monomeric or oligomeric DNA molecules in EV carcinomas, and frequently contain deletions. This is in contrast with HPV DNA sequences in genital cancers, which are often integrated into the host DNA. Evidence for the transcription of HPV-5 genomes in primary and metastatic EV carcinomas has recently been obtained. The available data indicate that HPV-5 and some HPV-5-related types have an oncogenic potential and play a role in the malignant transformation of EV lesions. Infection by these HPVs must be considered a major risk factor for the development of cancers in EV patients. EV HPV DNA sequences have only rarely been detected in premalignant or malignant lesions of the skin in the general population. This further stresses the role of genetic, immunological and extrinsic factors in the abnormal susceptibility of EV patients to a set of specific HPV types.

Detection and identification of human papillomavirus types isolated from Korean patients with flat warts

Flat warts, also called verruca planna (VP) or juvenile warts, are benign epithelial proliferations of the skin caused by infection with human papillomaviruses (HPV). Several HPV types are known to be associated with flat warts, and particularly HPV type 3 and 10 have been most frequently reported in other countries. In this study, for the detection and typing of human papillomavirus isolated from Korean patients with flat warts, polymerase chain reaction (PCR) and restriction endonuclease digestion were carried out with a set of restriction endonucleases, using the cloned HPV DNA and DNA from clinical specimens. A unique digestion pattern for HPV type 3 and 10, a form of miniature fingerprinting, enabled us to identify HPV type from the amplified fragments. A total of thirty clinical samples, as either frozen tissue or paraffin-embedded tissue, were investigated to verify the type. All the clinical samples except one were con-firmed to be type 3, one of the most frequently observed types in flat warts, and one sample was neither type 3 nor type 10. Further investigation of the unidentified sample by DNA sequencing and sequence alignment with other known HPV types revealed that the sample was a variant of HPV type 94, one of the EV-related HPVs, with the closest evolutionary distance to the HPV type 10 among the known flat wart-associated HPV types.

Human papillomaviruses in the normal oral cavity of children in Japan

The purpose of this study was to determine the frequency of human papillomavirus (HPV) infections in the normal oral cavity of children in Japan. Oral squamous cell specimens were collected from 77 children (44 boys and 33 girls), aged 3 and 5 years. Extracted DNA was evaluated for HPV infections by polymerase chain reaction (PCR) methods, using consensus primers for the L1 region, specific primers, and direct DNA sequencing analysis. Thirty-seven of 77 specimens (48.1%) were positive for HPV DNA. Positive rates of boys and girls in all specimens were 28.3 (22/77) and 19.5 (15/77)%, respectively. The positive rate in 3-year-old children was 45.2 (14/31)%, and positive rates in boys and girls were 52.6 (10/19) and 33.3 (4/12)%, respectively. The positive rate in 5-year-old children was 50.0 (23/46)%, and positive rates in boys and girls were 48.0 (12/25) and 52.4 (11/21)%, respectively. HPV types were determined by specific PCR and direct DNA sequencing analysis. Frequent HPV types in the specimens of all children were HPV-16 (11/37; 29.7%),-1 (6/37; 16.2%),-2 (6/37; 16.2%),-75 (6/37; 16.2%). The results of the present investigation indicate that many HPVs, including HPV-16 (a high-risk type for cancer), are present in the oral cavity of 3- and 5-year-old children. It is suggested, therefore, that the oral cavity is already a reservoir of HPVs in childhood where later HPV-associated diseases, such as oral cancer and other oral lesions, may develop.

The relationship of human papillomaviruses to anorectal neoplasia

This review begins with an overview of the anatomy of the anal canal, which is followed by a discussion of human papillomavirus (HPV) infections in the anogenital tract. The organization of the HPV genome and the function of the encoded proteins is discussed in relation to the oncogenic potential of these viruses. Particularly stressed are interactions with known tumor suppressor genes. Then the interaction of HPV with the host cells and some growth factors is reviewed. An important consideration is the synergy between this virus and other known carcinogenic factors. These include smoking, immunologic status, and other factors. Finally, the pathologic features of anal warts and malignant lesions are summarized with respect to their histologic findings and expression of viral subtypes.

Implication of human papillomavirus in postirradiation dysplasia

The presence of human papillomavirus (HPV) DNA and association of condylomata acuminata (CA) in the biopsy tissues of postirradiation dysplasia (PRD) of the cervix and/or vagina from 17 patients who previously had radiation therapy for malignancies of the uterine cervix, vagina, and endometrium were evaluated with DNA in situ hybridization. Eight of 17 patients (47.1%) had HPV DNA identified in the lesions of postirradiation dysplasia (PRD). Five of eight cases (62.5%) contained HPV DNA of more than one type. Type 16 HPV DNA (HPV-16) was the most frequently identified type. Several PRD lesions also contained HPV-6, HPV-18, HPV-31, and/or HPV-33 DNA. Eleven patients (64.7%) showed CA in the vicinity of PRD. In two cases, different types of HPV were found in the lesions of PRD and contiguous CA. The frequency of the cases containing HPV DNA, the types of HPV, and the distribution pattern of silver grains in the preparations of in situ hybridization over the nuclei of cells of PRD were very similar to those found in naturally occurring dysplasia. Based on these findings, persistent or repeat HPV infection was the most likely etiologic factor of PRD, which might be facilitated by immunosuppression due to pelvic irradiation.

Condylomata acuminata in children: frequent association with human papillomaviruses responsible for cutaneous warts

To identify the papillomavirus types associated with condylomata acuminata in children and to evaluate their mode of transmission, we studied 32 children with anogenital warts. External condylomata were found in 12 of their mothers and in 10 of their fathers. Ten mothers, including two without external lesions, had cervical condylomata. Blot hybridization studies disclosed a genital human papillomavirus (HPV) in 14 of 27 children (HPV-6 in 12 and HPV-11 in two) and in 8 of 14 patients (HPV-6 in all). HPV-6 was found in another child by the polymerase chain reaction technique. Infection occurred most likely at birth or from nonsexual contact, but sexual abuse could not be excluded in one 11-year-old girl. Cutaneous HPV-2 was found in seven children and as yet uncharacterized papillomaviruses were found in two children. Three mothers of HPV-2-infected children had common hand warts, and two children had subungual warts. This study shows the frequent nonsexual transmission of genital papillomaviruses in children and the unexpectedly high association of children's condylomata with papillomaviruses responsible for skin warts, possibly transmitted by heteroinoculation or autoinoculation.

Antigen presentation and T-cell activation in epidermodysplasia verruciformis

Aberrant immune responses may play a role in the susceptibility of patients with epidermodysplasia verruciformis to human papilloma virus (HPV). We examined the stimulatory capacity of antigen-presenting cells from HPV-infected skin and peripheral blood T-cell responses of patients with epidermodysplasia verruciformis. The percentage of Langerhans cells in relation to total epidermal cells in suspension was slightly reduced in HPV-infected lesions, relative to apparently clinically uninfected epidermis. In addition, the morphologic appearance of Langerhans cells was altered in lesional epidermal sheets. Despite these abnormalities, Langerhans cells were functionally intact in their capacity to present alloantigens to T cells and, in fact, the epidermis of HPV-infected lesions demonstrated enhanced antigen-presenting activity in three of four patients tested. The antigen-presenting activity was entirely abrogated by removal of Langerhans cells and was not associated with increased activity of cytokines with stimulatory activity for the thymocyte co-stimulation assay. Although epidermodysplasia verruciformis T cells were unresponsive to autologous HPV-infected epidermis, they responded well to mitogens, allogeneic mononuclear leukocytes, and allogeneic epidermal cells. Epidermodysplasia verruciformis T cells were inhibited in their capacity to respond to allogeneic epidermal cells when they were simultaneously exposed to autologous epidermal cells from HPV-infected lesional epidermis, but not to normal-appearing epidermis. Thus, although Langerhans cell activity is intact in epidermodysplasia verruciformis, these individuals fail to respond to autologous papillomas, which may, at least in part, be explained by an interaction between papillomal epidermal cells and autologous T cells that results in an inhibited response.

Risk of cervical cancer among wives of men with carcinoma of the penis

The relationship between carcinomas of the penis and cervix uteri was analyzed in married couples. The final series comprised 239 patients with squamous cell carcinoma of the penis and their 224 wives. Two wives were found to have squamous cell carcinoma of the cervix uteri. The expected number of cervical cancers within the group of wives was 1.88, the relative risk thus being 1.05 (95% confidence interval 0.13-3.8). The incidence of condylomas has increased during the recent decades, while that of carcinomas of the penis and uterine cervix has decreased. The results of this study did not support the hypothesis that wives of men with penile cancer incur an increased risk of carcinoma of the cervix uteri. Although there is much evidence from a large number of studies that human papilloma virus (HPV) has a role in the aetiology of cervical cancer, our study suggests that HPV associated with genital malignancies has a low infectivity or that these cancers have multifactorial aetiology.

Detection of human papillomavirus deoxyribonucleic acid by filter in situ hybridization during pregnancy

Samples taken from 101 healthy pregnant women (49 over and 52 under the 20-week gestational period) and 108 healthy nonpregnant women were tested for human papillomavirus (HPV) types. Using 6, 11, 16, and 18 HPV DNA probes, 3-5 x 10(5) exfoliated cells scraped from the cervix were tested by filter in situ hybridization (FISH). Thirty-five of the pregnant women (34.6%) had evidence of the presence of HPV DNA: with 11.8% (12/101) HPV 6; 7.9% (8/101) HPV 11; 8.9% (9/101) HPV 16; and 5.9% (6/101) HPV 18 positivity. HPV DNA was detected in 20.4% (22/108) of the non-pregnant women. Compared with the healthy, nonpregnant group, the higher level of asymptomatic cervical HPV infection was mainly due to the accumulation of HPV 16 and 18 nucleic acids during the gestational period: with detection of HPV 16 in 8/49 cases (16.3%) and of HPV 18 DNA sequences in 4/49 (7.6%) cases. Screening 6-8 weeks after delivery indicated a decline of HPV positivity. Of the 4/12 HPV type 16 positive mothers, only one retained the presence of HPV 16 DNA, whereas neither of the 2/12 type 18 positive women reacted after birth with the type 18 radioactive probe.

Human papillomaviruses and carcinomas

The recognition of multiple types of human papillomaviruses has resulted in remarkable progress in the detection of persisting viral nucleic acid sequences in carcinomas. The consistent transcription in tumors of two early open reading frames, E6 and E7, with few exceptions (Lehn et al., 1985), indicates a role for the products of these genes in the induction and/or maintenance of the transformed state. A number of studies have shown that in vitro transformation can be achieved by transfection of E6/E7 DNA, and proteins encoded by these DNA sequences can be demonstrated in primary human keratinocytes immortalized by this DNA (Kaur et al., 1989). Mutagenesis experiments are needed to determine the absolute requirement for and function of these genes in transformation. A preferential association of some types with benign lesions while others may be frequently found in malignant tumors has been observed. HPV types 5 and 8 in epidermodysplasia verruciformis patients and types 16, 18, 31, 33, etc. in genital lesions are most frequently associated with progression to malignancy, whereas other types, such as HPV-6,-10, -11, and -20, are regularly identified in benign warts. Such distinctions are not absolute but provide the initial steps toward establishing a causal role for some human papillomaviruses in carcinomas. The need for well-designed epidemiological studies in concert with optimum molecular and serologic evaluations is evident (Armstrong et al., 1988). The data from human and animal studies indicate that papillomaviruses contribute significantly to the development of many, if not all, carcinomas, but we do not yet have a clear understanding of the importance of other interacting viral, chemical, or cellular factors. The application of gene cloning and non-stringent hybridization (Law et al., 1979) has provided us with an apparently ever-increasing catalog of human papillomaviruses. More effort is now required to establish their prevalence, the natural history of infection, and the mechanism of neoplastic transformation.

Nucleic acid spot hybridization with nonradioactive labeled probes in screening for human papillomavirus DNA sequences

We examined 161 human tissue samples using the spot hybridization technique with nonradioactive labeled DNA probes of human papillomavirus (HPV). Whole cells were spotted on nitrocellulose filters; DNA of the cells was denatured and fixed to the filter. Then the DNA spots were hybridized to nonradioactive labeled DNA and monitored by a sandwich immunoenzymatic reaction. This technique is simple, sensitive, specific, requires no special equipment, and can be used in clinical settings. HPV DNA was found in 92% of samples in which, on the basis of histologic and colposcopic criteria, its presence was suspected, as well as in 31 samples where it was not suspected.

Malignant progression of laryngeal papilloma associated with human papilloma virus type 6 (HPV-6) DNA

A case of laryngeal squamous papilloma in the early stages of development showed histological features suggestive of virus infection. Five years later positive evidence of HPV-6 infection was obtained at a time when the lesion had developed into a squamous cell carcinoma. It is concluded that this case represents a complete example of the virus to papilloma to carcinoma sequence, and as far as is known, is the first reported case of its kind in the larynx.

Human papillomavirus DNA in normal, metaplastic, preneoplastic and neoplastic epithelia of the cervix uteri

Colposcopically directed cervical punch biopsies from 362 patients were screened by Southern blot hybridization for the presence of DNA of human papillomavirus (HPV) 6, 10, 11, 16, 18, 31 and 33. The biopsies represented original squamous epithelium, epithelium of metaplastic origin, different stages of cervical intraepithelial neoplasia (CIN) and invasive carcinomas. HPV6/11, 16, 18 and 31 were detected in 2.9% to 13.7% of histologically normal epithelia. HPV6/11 prevailed in CIN I. HPV16 was clearly more abundant than other HPV types in high-grade CIN and invasive cancers (50%-60%), compared with healthy epithelium. Restriction enzyme cleavage analysis of DNA from primary cancers and corresponding metastases proved the stable association of HPV16 DNA with invasive tumor cells. Preliminary follow-up studies of CIN II patients suggested that HPV16-associated lesions are relatively more likely to persist or to progress. Taken together, the data support the notion of a higher oncogenic potential of HPV16.

The biology and significance of human papillomavirus infections in the genital tract

A variety of human papillomavirus (HPV) types infect the anogenital mucosa, giving rise to lesions that differ in clinical appearance, histology, and risk of malignant progression. Certain high-risk types (HPVs 16, 18, 31, 33, 35 and 39) have a strong association with high-grade epithelial neoplasia and invasive carcinomas of the anogenital tract. Cancer appears to have a multifactorial etiology, and HPV infection alone is probably insufficient for malignant transformation. The consistent association between HPV infection and anogenital cancers emphasizes, however, that the sexually transmitted papillomaviruses may have a necessary role in carcinogenesis. Hence, there is a prospect that vaccination programs may one day allow public health control of HPV infection, thereby eliminating an important risk factor.

Detection of DNA of human papillomavirus types 6/11 and 16/18 in cell scrapings of the uterine cervix by filter in situ hybridisation. Correlation with cytology, colposcopy and histology

The application of filter in situ hybridisation (FISH) to detect the presence of the DNA of human papillomavirus genotypes 6/11 and/or 16/18 in cell scrapings of the uterine cervix of 248 women in Western Australia is described. The results obtained by FISH are related to cervical dysplasia as assessed by cytology, colposcopy and histology. The detection of HPV infection was more sensitive and specific by FISH than by either histological/cytological evidence of an HPV cytopathic effect (koilocytosis) or immunohistochemical staining for HPV capsid antigen using antiserum against genus specific antigen of the bovine papillomavirus. Viral DNA was detected by FISH in 65% of women with atypical cytology and of the HPV positive cases, 68% were HPV 16/18, 22% HPV 6/11 and 10% of mixed types. HPV-DNA was detected in the cervical smears of 16 women who also had HPV capsid antigen (HPV-Ag) in their cervical biopsies; HPV 6/11 was found in 4 cases and HPV 16/18 in 12 cases. The relative frequency of the HPV-Ag positive cases decreased markedly from 44% to 4% with an increase in the severity of cervical dysplasia. By comparison, the percentage of HPV-DNA positive cases remained relatively constant between 70% and 80% for all 3 categories of dysplasia. Of these, the percentage of HPV 6/11 positives decreased slightly with an increase in the severity of dysplasia as assessed by either cytology or histology, whereas the percentage of HPV 16/18 positive cases was relatively constant. HPV-DNA was found in cervical smears of 11 of 48 (23%) women who were diagnosed colposcopically to have atypical transformation zone of the cervix. In 138 women with an atypical transformation zone, 96 (70%) were found to have HPV-DNA with HPV 16/18 contributing to 83% of the HPV positive cases. All four genotypes of HPV were found to be associated with the colposcopic morphology of mosaicism (26 cases) but only HPV 16/18 was found in 12 HPV-DNA positive cases associated colposcopically with punctation and an atypical transformation zone. The detection and typing of HPV-DNA in cell scrapings by FISH is a relatively fast and non-invasive procedure which complements cytology, colposcopy and histology and should be useful in further studies of the natural history of different HPV infections and their role in cervical cancer.

The molecular biology of human papillomaviruses and the pathogenesis of genital papillomas and neoplasms

Numerous studies over the past several years have demonstrated that human papillomaviruses (HPV) may play a significant role in the development of several types of human neoplasia. Although it has been accepted for some time that HPVs are responsible for benign epithelial tumors, data accumulated in more recent years have implicated this group of animal viruses in a number of premalignant lesions, as well as a variety of epithelially derived malignancies. Genital, oral, and some rare types of cutaneous cancers have all been found to contain varying degrees of HPV DNA. In several instances secondary tumors resulting from metastases to lymph nodes and lungs have also been demonstrated to contain HPV DNA. Although there is a strong correlation between the presence of the virus and the malignant phenotype in several of these cancers, the precise role of the virus in the development of malignant tumors has not yet been elucidated. A major difficulty in elucidating the role of papillomaviruses in oncogenesis has been the lack of an appropriate in vitro culture system that would permit the growth of the virus and allow an analysis of its transforming properties. Nevertheless, recent advances in molecular biology have permitted the molecular cloning and amplification of HPV viral DNA, thereby facilitating its use as a probe for the detection of miniscule amounts of HPV DNA and HPV RNA in tumor biopsies. Moreover, DNA transfections of cells in culture have been extremely useful in the study of viral DNA replication and transformation properties, providing information on the maintenance and oncogenicity of HPV DNA. These advances have implications for the improved detection of HPV infections, which will aid in patient diagnosis and prognosis. In addition, future treatment and prevention programs may come as a direct result of these basic studies on the mechanism of HPV-induced oncogenesis.

Sensitivity of the cytologic diagnosis of cervical condyloma in comparison with HPV-DNA hybridization studies

The cytologic diagnosis of cervical condyloma is based on criteria developed over the last 10 years. It has now become possible to document the presence of human papilloma virus (HPV) DNA directly in cervical swabs by the highly sensitive technique of DNA filter hybridization in situ. The purpose of this article is to evaluate critically the empirically established cytologic criteria of condyloma by comparing them with HPV-DNA hybridization studies in the same material. The results of this study indicate that "classic" koilocytosis and dyskeratocytosis are not highly sensitive criteria for the presence of HPV infection, identifying only 15% of the HPV-DNA-positive cases correctly. In an attempt to improve the sensitivity of the cytologic diagnosis of HPV infections, a panel of nine "nonclassic" criteria was evaluated. The five most valuable signs were "mild koilocytosis," mild dyskeratocytosis," hyperchromatic nuclei, bi- and multinucleation, and cleared cytoplasm. Using these criteria in combination, statistically discriminant analysis could correctly identify 84% of the HPV-positive group.

Identification of human papillomavirus types in male urethral condylomata acuminata by in situ hybridization

An in situ hybridization technique was applied under stringent conditions to paraffin sections of urethral condylomata from male patients to determine the presence of DNA sequences of human papillomavirus (HPV) types 6, 11, 16, and 18. The material consisted of 15 classical condylomata acuminata, two flat condylomata, and five recurrent lesions. HPV DNA sequences could be identified in all 15 condylomata acuminata; in 13 lesions, two types of viral DNA were observed (types 6 and 11 in 12, types 6 and 18 in one). In the remaining two condylomata acuminata, only HPV type 11 was present. One of the two flat condylomata was negative with all the probes, and one was borderline-positive for HPV 6. Four of five recurrent lesions contained the same types of viral DNA as the primary lesions, albeit with slight differences in the intensity of viral expression. One lesion was negative with all probes. We conclude that urethral condylomata in males contain the same types of HPV as seen in other anogenital lesions of both sexes and that infection with two viral types is common. In situ hybridization with HPV DNA probes is applicable to archival material and therefore may prove to be of value in future epidemiologic studies comparing lesions in sexual partners. The determination of viral type may have therapeutic implications.

Human papillomavirus type 17 transcripts expressed in skin carcinoma tissue of a patient with epidermodysplasia verruciformis

Certain types of human papillomavirus (HPV) are involved in skin carcinogenesis in epidermodysplasia verruciformis. However, no gene or gene product of HPV associated with skin carcinogenesis has yet been identified. Here, we report HPV-17 transcripts expressed in skin carcinoma tissue of an epidermodysplasia verruciformis patient infected with HPV-17. Further, we show that one of these transcripts was localized to a portion of the genome which contains the 3' open reading frames of the early region (E2, E3, E4 and E5). The analogous region in bovine papillomavirus type I has been shown to contain a transforming gene (Nakabayashi et al., 1983; Sarver et al., 1984; Yang et al., 1985a).

Condylomata acuminata (genital warts). An epidemiologic view

The understanding of condylomata acuminata (genital warts) has been enhanced by the recent development of diagnostic methods. Forty-two types of human papillomavirus were identified up to 1985, and at least sixteen types were involved in genital warts. The incidence of genital warts is around 0.1% in the general population and more than 0.5% in young persons. The incidence is known to be increasing rapidly and exceeding the incidence of genital herpes. Females are more prone to be affected. The epidemiologic evidence supporting the relationship between genital warts and genital cancer is overwhelming. The evidence also speaks for a strong correlation between genital warts and verrucous carcinoma of the genitalia, bowenoid papulosis, and laryngeal papilloma. The person having genital warts may also have other cutaneous warts. This observation is compatible with the finding that types of human papillomavirus involved in other cutaneous warts were found in genital warts. In view of the never and easier ways of diagnosing nonconspicuous condyloma acuminatum and the potential for malignant transformation of condyloma acuminatum, it is strongly recommended that patients should be followed up periodically for early detection of neoplasia.

Nucleic acid probes in clinical microbiology

The infectious disease applications of nucleic acid probe have been described. In addition, the basic procedures of nucleic acid probe technology have been discussed, as have the factors affecting implementation of probe technology in diagnostic laboratories. Despite the questions raised, nucleic acid probes will become part of the diagnostic laboratory in the near future. Commercial interests are developing and marketing new probes, reagents, and kits which will expedite the employment of this technology. High-volume reference laboratories will first use probes as part of a battery of tests which will include ELISA and monoclonal antibody methods. In all probability, probes will replace methods: that have proven to be ineffective, difficult, or costly such as culturing for some enteric pathogens and Legionella, that require long incubation periods, such as mycobacteria, or that have high costs and low yields, such as virology.

Rat embryo fibroblast cells expressing human papillomavirus 1a genes exhibit altered growth properties and tumorigenicity

Human papillomavirus 1a (HPV1a) induces benign tumors (papillomas or warts) in humans under natural conditions of infection but has not been found to replicate significantly in cell culture or in experimental animals. To establish model systems to study the oncogenic properties and expression of HPV genes, we established cell lines by cotransfecting the 3Y1 rat fibroblast cell line with HPV1a DNA constructs containing an intact early gene region and the Tn5 neomycin resistance gene. Most cell lines selected for expression of the neomycin resistance gene by treatment with the antibiotic G-418 contained viral DNA in a high-molecular-weight form. The growth characteristics of several cell lines containing high copy numbers of HPV1a DNA were studied further. They were shown to differ from the parental cell line and from G-418-resistant cell lines that did not incorporate viral DNA in the following properties: morphological alteration, increased cell density at confluence, growth in 0.5% serum, efficient anchorage-independent growth in soft agar, and rapid formation of tumors in nude mice. Those cell lines that possessed altered growth properties and tumorigenicity were found to express abundant quantities of polyadenylated virus-specific RNA species in the cytoplasm.

Human papillomavirus infection of the uterine cervix of women without cytological signs of neoplasia

One hundred and six patients were studied whose cervical smears showed only non-specific inflammatory changes. Screening for genital pathogens yielded only a few positive cases. Histological examination of biopsy specimens taken by colposcopically directed tissue sampling showed cervical intraepithelial neoplasia in 13 of the women (12.3%). Deoxyribonucleic acid (DNA) hybridisation techniques were used to detect human papillomavirus, which was found in 24 patients (22.6%). In a second group of 104 patients with normal cervical cytology tissue biopsy samples were obtained and examined histologically but in no case was cervical intraepithelial neoplasia found. On DNA hybridisation, however, 12 patients (11.5%) were found to be positive for human papillomavirus. In this group finding human papillomavirus DNA was usually associated with a columnar ectopy. An association between human papillomavirus type 16 DNA and both cervical intraepithelial neoplasia and cervical cancer is well established. In this study it was type 16 which occurred most frequently in both groups.

Cancers of the anogenital region in renal transplant recipients. Analysis of 65 cases

There is a 100-fold increase in the incidence of carcinomas of the vulva and anus in renal transplant recipients compared with the general population. Anogenital (anus, perianal skin, and external genitalia of both sexes) carcinomas occurred in 65 of 2150 renal transplant recipients who presented with 2298 different types of malignancy. Two-thirds of the patients were female and one-third male. They were much younger than persons with similar tumors in the general population. The average age of the females at the time of diagnosis was 37 years (range, 20-64) and of the males, 45 years (range, 34-62). The neoplasms occurred late after transplantation, an average of 88 months (range, 9-215), compared with an average of 56 months (range, 1-225.5) for all other post-transplant malignancies. The lesions involved the vulva, penis, scrotum, anus, or perianal area. Two patients also had involvement of the urethral meatus. In several female patients, there was a "field effect" with multiple tumors of the squamous epithelium of the anogenital area, vagina, or uterine cervix. Lesions ranged from in situ carcinomas (in one-third of the cases) to those with invasion of adjacent organs and lymph node metastases. Treatment varied from local excisions to radical vulvectomy, abdominoperineal resection, or penile resection, sometimes combined with excision of the inguinal lymph nodes. In several patients, there was a previous history either of condyloma acuminatum or herpes genitalis, suggesting a possible viral etiology of these tumors.

The role of human papillomaviruses in the pathogenesis and histologic classification of precancerous lesions of the cervix

It is clear that the relation between HPV infection and cervical neoplasia is more complex than initially realized. Preliminary molecular virologic data suggest preferential distributions of low- and high-risk HPV types in CIN that tend to correlate with the morphologic appearance. Thus, mild and moderate dysplasias (CIN I and II) contain a diverse distribution of HPV types, including a minority that have a high risk of malignant potential. HPV, therefore, appears to play a major role as a promoter. Neoplastic transformation is probably determined by specific HPV types but, in addition, requires initiation by some other carcinogenic stimulus, e.g., HSV II, cigarette smoking. Despite numerous studies, performed during the past 30 years, the long-term behavior of dysplasia remains uncertain. The natural history of HPV-associated lesions is unknown. Until this information is available, it is recommended that the conventional dysplasia--CIS or CIN nomenclature be used. The presence of associated viral changes can be considered and added to the diagnosis, e.g., "moderate dysplasia (CIN II) with evidence of papillomavirus infection." Treatment should be the same for all intraepithelial lesions, regardless of the presence of morphologic evidence of HPV. In the future, it may be necessary to modify the classification of precancerous lesions of the cervix if it is shown that a specific HPV type induces a characteristic morphologic alteration or that the HPV type, in and of itself, has greater prognostic significance. Until then, confusion will be minimized and management optimized if the conventional dysplasia--CIS or CIN nomenclature is employed.

The demonstration of papilloma virus in cervical dysplasia and/or neoplasia

Thirty-three random biopsy specimens of uterine cervix were studied by immunoperoxidase technique to evaluate the presence of HPV antigen in dysplastic and neoplastic cells. Four cases of mild dysplasia, nine cases of moderate to severe dysplasia, two cases of carcinoma in situ and one case of invasive carcinoma were associated with condylomatous lesions. Intranuclear dark-brown precipitates were observed in superficial and intermediate zones of the dysplastic epithelium. Positive reaction was seen in condylomatous epithelium associated with neoplasia. No nuclear precipitates were observed in carcinoma cells, but one noncondylomatous lesion with moderate dysplasia showed positive intranuclear staining. These preliminary findings suggest that papilloma viruses may play a role in the development of human cervical neoplasias.

Cloning and characterization of the DNA of a new human papillomavirus from a woman with dysplasia of the uterine cervix

A previous analysis of 121 female genital tract lesions from the United States and South America had revealed that a large number contained DNA sequences that were weakly homologous to a panel of human papillomavirus (HPV) probes. The DNA sequences of one of these viruses have been molecularly cloned and shown to be a new type of HPV which is called HPV 31. Among the cloned HPV genomes, HPV 31 is most closely related to HPV 16. Although absent from all genital condylomas studied, HPV 31 was present in approximately 20% of the mild and moderate dysplasias and in 6% of the invasive cervical cancers

Analysis of benign and malignant urogenital tumors for human papillomavirus infection by labelling cellular DNA

A total of 268 biopsies from the genital region was screened for the presence of human papillomavirus DNA. The specimens included carcinoma of the vulva, vagina, cervix, corpus uteri, ovaries and penis, and Bowen's carcinomas, Bowenoid papuloses, Bowen's disease, cervical intraepithelial neoplasias (CIN I to III), Buschke-Löwenstein tumors, a cervical polyp, decidua, endometrium and histologically normal biopsies. Of 45 carcinomas, 18 contained either HPV 16 and/or 18 and 3 HPV 6-related sequences. In a few individual biopsies double or even triple infections were noted. Unusual was the presence of HPV 2-related DNA in one biopsy from Bowen's disease, whereas 2 condylomata acuminata contained HPV 3-related DNA and one contained HPV DNA related to a group of epidermal HPV's found in epidermodysplasia verruciformis lesions.

Papillomavirus infection of the anogenital region: correlation between histology, clinical picture, and virus type. Proposal of a new nomenclature

The clinical and histologic picture of 84 anogenital condylomatous and condyloma-like lesions of both sexes were analyzed in an effort to establish a correlation to the different papillomavirus (PV) types. The presence of human papillomavirus (HPV)-specific DNA sequences was confirmed through molecular hybridization and the presence of PV structure antigens was verified in thin sections by means of a group-specific anti-PV-antiserum using the peroxidase-antiperoxidase (PAP) technique. Three distinct clinical forms harboring distinct HPV types were distinguished: (1) Condylomata acuminata in which HPV-6 DNA was present in 37 of 59 samples and HPV-11 DNA in only 13 of 59 samples. HPV-16 DNA was not detected at all and 9 condylomatous lesions remained unclassified. (2) Flat condyloma-like lesions, where HPV-6 and HPV-11 were associated with lesions of low epidermal atypia in 8 and in 2 of 18 cases, respectively, and where HPV-16 was associated exclusively with 6 of 18 such lesions with severe atypia, called bowenoid papulosis. (3) Pigmented papules where HPV-16 was detected twice in lesions of bowenoid papulosis and HPV-11 in 2 of the benign pigmented lesions. The fourth clinical manifestation of genital papillomavirus infections--the so-called condylomata plana--was not available for virologic analysis. Histologically 5 different koilocytotic features were determined which could not be correlated either with one of the clinical pictures or with a specific PV type. HPV-16, however, was found frequently in non-koilocytotic lesions exhibiting the features of severe epithelial atypia known in bowenoid papulosis. The existence of PV structure antigens in these lesions could not be verified using the indirect immunoperoxidase--PAP-technique--in contrast to the koilocytotic lesions where clear evidence of the presence of HPV was proved in 36 of 56 (64.3%) of the cases.

Herpes simplex virus type 2 and human papillomavirus type 16 in cervicitis, dysplasia and invasive cervical carcinoma

Sera and biopsies of cervical lesions from 55 women with benign or malignant disease were analyzed for evidence of infection with herpes simplex virus type 2 (HSV-2) or human papillomavirus (HPV). In addition, information regarding known risk factors for cervical cancer was obtained by interview. The sera were tested for HSV-2 antibodies and the biopsies were tested for HPV or HSV DNA sequences by Southern blot hybridization. HSV-2 sequences were detected in 2/13 (15%) invasive neoplasms and in 1/12 (7%) benign lesions. Under non-stringent conditions of hybridization, reactions with HPV DNA were detected in biopsies of 2/17 (12%) inflammatory lesions, 6/12 (50%) intraepithelial neoplasms and 13/20 (65%) invasive neoplasms. All but one of the positive biopsies of invasive cancer, but only 4/11 biopsies of non-invasive lesions, contained HPV-16 DNA as determined by stringent hybridization conditions. Women with cervical cancer possessed the risk factors associated with the disease. Cigarette smoking and the presence of HPV-16 DNA were the most prominent risk factors. No evidence of an interaction between HSV-2 and HPV-16 was found among the cases of invasive cervical cancer.

Molecular cloning and characterization of the genomes of nine newly recognized human papillomavirus types associated with epidermodysplasia verruciformis

The genomes of 11 human papillomaviruses (HPVs) found in benign lesions of eight patients suffering from epidermodysplasia verruciformis were cloned in Escherichia coli after insertion into plasmid pBR322. The study of the sensitivity of the cloned HPV DNAs to 14 restriction endonucleases permitted the construction of physical maps. DNA-DNA hybridization experiments, performed under stringent conditions, showed that these viruses represent nine new types, HPVs 14 (with subtypes a and b), 15, 17 (with subtypes a and b), 19, 20, 21, 22, 23, and 24. These HPVs were divided into three groups based on an absent or very weak cross-hybridization among the genomes of the viruses belonging to different groups.

Response of warts in epidermodysplasia verruciformis to treatment with systemic and intralesional alpha interferon

The susceptibility of human papillomavirus infection to polyclonal human leukocyte interferon (IFN-alpha) has been evaluated in patients with epidermodysplasia verruciformis (EV), a disease with extensive chronic papillomavirus-induced warts. In a double-blind, placebo-controlled study with intralesional IFN-alpha, four of five IFN-alpha-treated warts regressed; none of the placebo-treated warts responded (p = 0.024). Three patients with EV were treated with systemic IFN-alpha for 4 weeks in an open study, achieving partial regression of warts in all three. In a double-blind, placebo-controlled study, warts in two children with EV regressed with systemic IFN-alpha while two who received placebo showed no improvement. The lesions recurred following cessation of therapy. At the completion of therapy with IFN-alpha, histologic normalization was accompanied by a 95% decrease in the number of viral antigen-containing cells in the warts (p less than 0.001). We conclude that warts in EV respond to systemic and intralesional IFN-alpha.

Clinical observations, virologic studies, and treatment trials in patients with epidermodysplasia verruciformis, a disease induced by specific human papillomaviruses

We have studied 11 patients with the papillomavirus-induced disease epidermodysplasia verruciformis (EV). Clinical diagnostic features are widespread, long-lasting, pityriasis versicolor-like macules and flat, wart-like papules, both usually occurring in early childhood, with the subsequent development in the third decade of multiple skin cancers of the Bowenoid in situ and squamous cell types, primarily in sun-exposed skin. Virologic studies using the methods of immunofluorescence microscopy, restriction endonuclease analysis, and DNA blot hybridization have shown benign lesions to be associated with one or several types of the human papillomaviruses (HPVs) specifically associated with EV (at least 15 types recognized on the basis of sequence homology studies of molecularly cloned genomes). Skin cancers in these patients were associated with the genomes of either HPV-5, HPV-8 or HPV-14, suggesting that these three viruses are potentially oncogenic. A genetic factor appears to play a role in the pathogenesis of EV, since 5 of our patients were children of consanguineous parents and 2 had siblings also suffering with EV, suggesting a recessive inheritance pattern. Treatment of 4 EV patients with an oral retinoid resulted in partial temporary improvement of benign lesions, and the treatment of 2 patients with intralesional interferon injections into multiple Bowenoid cancers in situ has resulted in the disappearance of these lesions. Finally, EV serves as a model for studying the interplay of oncogenic viruses, genetic and immunologic factors, and sunlight in the production of skin cancer in humans.

HSV, CMV, and HPV in human neoplasia

We are studying the role of sexually transmitted viruses in the development of human tumors. The persistence of herpes simplex virus, cytomegalovirus, and human papillomavirus nucleic acid sequences has been examined using cloned viral DNA sequences as probes. The relationship of the viruses to various stages in the progression of neoplasia is examined, with particular reference to the role of viral and/or cellular genes in the initiation, promotion, and maintenance of the neoplastic phenotype. The human tumors of major interest in this context are carcinomas of the cervix, vulva, and anus and Kaposi's sarcoma. The minimal fragment of HSV-2 DNA detected in cervical tumors is contained within a 656-bp sequence that can be used in transfection experiments to transform rodent cells in vitro to a malignant phenotype. However, neither this fragment nor any other is consistently retained in cervical tumors, suggesting that this viral DNA may initiate but not maintain the transformed phenotype.

A new type of papillomavirus DNA, its presence in genital cancer biopsies and in cell lines derived from cervical cancer

DNA of a new papillomavirus type was cloned from a cervical carcinoma biopsy. Two EcoRI clones of 7.8 and 6.9 kb in length were obtained, the latter contained a 900-bp deletion. The BamHI fragments of both clones were used to characterize the DNA. It represents a distinct type of papillomavirus as determined by its size, its cross-hybridization with DNA of other papillomavirus types under conditions of low stringency only, the co-linear alignment of its genome with HPV 6 and HPV 16 prototypes and its occasional occurrence as oligomeric episomes. We tentatively propose to designate it as HPV 18. DNA hybridizing with HPV 18 under stringent conditions was detected in 9/36 cervical carcinomas from Africa and Brazil, in 2/13 cervical tumors from Germany and 1/10 penile carcinomas. Benign tumors (17 cervical dysplasias, 29 genital warts), eight carcinomata in situ and 15 biopsies of normal cervical tissue were devoid of detectable HPV 18 DNA. HPV 18-related DNA was found, however, in cells of the HeLa, KB and C4-1 lines all derived from cervical cancer. The state of the viral DNA was investigated in four cervical cancer biopsies. The data reveal that the DNA might be integrated into the host cell genome. One tumor provided evidence for head to tail tandem repeats some of which persisted as circular episomes.

Molecular cloning and characterization of a unique type of human papillomavirus from an immune deficient patient

Several papillomas from a single patient who exhibited an unusual immune deficiency syndrome were analyzed for the presence of specific human papillomavirus (HPV) types. Preliminary analysis indicated that the HPV DNA species present in each of these tissues was quite unlike any of the previously characterized HPV types. In order to more rigorously analyze the HPV from this patient we have isolated the HPV DNA by molecularly cloning it into a bacteriophage lambda vector and have constructed a detailed restriction endonuclease map. Comparative hybridization studies using S1 nuclease analyses showed 6% or less nucleotide sequence homology of this viral DNA with HPV types 1, 2, 3, 4, 5, 6, or an HPV-11, molecularly cloned in this laboratory. Moreover, Southern blot analyses under stringent hybridization conditions revealed little, if any, hybridization to HPV types 1, 2, 4, 5, 7, 8, 10, 11, HPV-EV isolated from a patient with epidermodysplasia verruciformis (EV), or 2 previously described HPVs (HPV-P and HPV-PW) related to HPV-3. There was, however, a very weak sequence homology detected with HPV-6 and an extremely weak homology to HPV-3. No filter hybridization was observed with the recently characterized HPVs 9 or -12 to -24. These data accumulatively indicate that the HPV species from this immunosuppressed patient represents a new, hitherto unidentified HPV type.

Tumour induction in the rodent Mastomys natalensis by activation of endogenous papilloma virus genomes

Specific DNA sequences from human papillomavirus have recently been detected in carcinomas from epidermodysplasia verruciformis patients, and in vulvar and cervical carcinomas but the role of papilloma viruses in the aetiology of these tumours is unclear. Indeed, little is known about the mechanisms that convert benign papillomas into malignant tumours and it is not even possible in tumour induction. Here, we describe an animal system that permits an analysis of the interaction of papilloma virus genomes with carcinogenic agents at the molecular level. In our colony of Mastomys natalensis (a close relative of the rat family), we have found extrachromosomal papilloma virus genomes persisting in a variety of tissues such as skin, muscle, liver and colon. With the ageing of the animals, the average copy number of viral DNA in skin cells increases and virus-producing tumours begin to appear in Mastomys at about 1 year old. This process is drastically enhanced by chronic treatment with a tumour promoter and transcription of the viral genomes has been found to be correlated with tumour formation.

Genital warts and cervical cancer. III. Subclinical papillomaviral infection and cervical neoplasia are linked by a spectrum of continuous morphologic and biologic change

Human papillomaviral (HPV) infection is now widely advanced as an important etiologic factor in cervical cancer. This study was undertaken to clarify morphologic relationships within the biologic spectrum linking subclinical papillomaviral infection (SPI) to cervical intraepithelial (CIN). Two pathologists analyzed 72 colposcopic biopsies, using a semi-objective rating scheme that scored 24 different histologic criteria. Each individual criterion was checked for reproducibility, and validated against an objective measure of papillomaviral infection (immunoperoxidase staining) or premalignant change (microspectrophotometry). The individual criteria were then combined into histologic indices of benign warty change, presumed viral atypia, abnormal cell phenotype, and disturbed tissue maturation. Histologic expression of papillomaviral infection decreased with increasing degrees of premalignant change. Plotting the index of abnormal cell phenotype against that of disturbed tissue maturation produced a linear plot in which cases clustered into four diagnostic groups. The histologic indices of papillomaviral infection displayed significant curvilinear correlations with genotypic distortion, benign warty change being maximal in the CIN 1 range and presumed viral atypia in the CIN 2 range. Disturbance of nuclear DNA content also increased with worsening diagnosis; diploidy being most common in SPI (67%), polyploidy in CIN 1 (59%), and aneuploidy in CIN 2 (65%) and CIN 3 (82%). Conversely, capsid antigen production decreased from 36% in SPI to 9% in CIN 3. Three aneuploid epithelia were immunoperoxidase positive. These inverse relationships between late viral expression and nuclear distortion fit experimental models of viral oncogenesis. The gradual transition and morphologic overlap between diagnostic groups support the postulate that SPI and CIN are a single disease spectrum, in which differences are those of degree rather than of kind.