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

Typing and molecular characterization of human papillomaviruses in genital warts from South African women

Condyloma acuminata from 12 women were examined for the presence of human papillomavirus DNA. Six of the women had HPV 6a, two had HPV 11a, one had a new HPV 6 subtype, and one a new HPV 11 subtype. The new HPV 6 subtype could be distinguished from other HPV 6 subtypes on the basis of Pst I fragments as well as Hind II fragments. The new HPV 11 subtype had a different Hpa II restriction endonuclease pattern. Restriction maps of both new subtypes were constructed. Two of the biopsies did not contain detectable HPV DNA when probed with HPV 6, HPV 11, and HPV 16. Biopsies were taken from normal tissue 1 cm away from the condyloma in 11 of the patients. Only one of these normal tissue biopsies was positive for HPV by Southern blot hybridization.

Efficacy of interferons on bowenoid papulosis and other precancerous lesions

Preliminary results of an open randomized trial of recombinant interferon gamma in patients suffering from bowenoid papulosis are described. Recombinant interferon gamma was given subcutaneously to 12 patients at a daily dose of 4 X 10(6) I.U. by injection. Four patients each were assigned to one of three treatment groups consisting of continuous therapy (group A) with three subcutaneous injections per week for 13 weeks; intermittent block therapy (group B) with four six-week cycles consisting of five injections on days 1, 3, 5, 7, and 9 of each cycle; and intermittent single-dose therapy (group C) with six four-week cycles consisting of only one subcutaneous injection on day one of each cycle. At the twenty-sixth week after onset of therapy, complete responses were seen in three of four patients of treatment group A, whereas in the treatment groups B and C only one patient, respectively, responded partially. These results suggest that in contrast to condylomata acuminata bowenoid papulosis lesions respond better to continuous than to intermittent interferon gamma injections.

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.

Molecular cloning of a novel human papillomarvirus (type 58) from an invasive cervical carcinoma

A novel human papillomavirus type (HPV) was cloned from an invasive cervical carcinoma. The viral clone showed no homology with other known prototypes of HPV (HPV-1 through HPV-57), except HPV-33 by Southern blot analysis under stringent conditions. It showed less than 20% homology to HPV-33 by reassociation kinetic analysis. The restriction endonuclease map of the clone was different from those of other HPV types and its predicted genome organization surmised by hybridization with subgenomic fragment probes of HPV-33 DNA showed the typical HPV genome organization. The results indicate that this clone is a new type of HPV, designated as HPV-58, distinct from the other known types of HPV. HPV-58 was detected in none of 6 specimens of cervical condylomata acuminata, in 7 of 58 specimens of cervical intraepithelial neoplasia, and in 4 of 50 specimens of invasive cervical carcinoma studied in Nagano prefecture, Japan.

Human papillomavirus infection and filaggrin expression in paraffin-embedded biopsy specimens of extragenital Bowen's disease and genital bowenoid papulosis

Cutaneous Bowen's disease (BD) and genital bowenoid papulosis (BP) are considered as precancerous or cancerous lesions that are sometimes infected with human papillomavirus (HPV). We studied retrospectively paraffin-embedded sections of 11 samples of cutaneous BD and 6 samples of genital BP from the general population for HPV infection and filaggrin expression. Using in situ hybridization with biotinylated probes of HPV types 1, 2, 5, 6, 11, 16, and 18, under stringent and/or non-stringent conditions and a streptavidin-alkaline-phosphatase complex for hybrid detection, HPV DNA was detected in 6/17 cases (5 BD and 1 BP). Positive nuclei were located in intermediate or upper epithelial cell layers. HPV 16 was found in 2 cases of BD but associated either with HPV 2 or 18. Three additional lesions reacted only under non-stringent conditions; HPV could not be typed with the probes used. The positive case of BP reacted with the four probe types 1, 2, 16, 18 and was negative with HPV 6 or 11. Viral antigen was not detected by indirect immunofluorescence with a rabbit antiserum directed to group-specific viral capsid antigen. Differentiation disorders were observed in the intermediate and upper cell layers of these specimens, as shown by a reduced expression of filaggrin/profilaggrin, a marker of terminal differentiation, in extragenital BD (7/11 cases), and an increased expression in genital BP (4/5 cases) although viral DNA was not always detectable. This study shows that in situ hybridization is a valuable technique for HPV DNA detection and its typing in BD and BP lesions on deparaffinized sections. The positive nuclei were located in the cell layers that exhibited abnormal expression of differentiation. There is no relation between the HPV infecting type and the filaggrin expression.

Apoptosis. The role of the endonuclease

Cell death by apoptosis mediates several important physiologic and pathologic processes and appears to be intrinsically programmed. Its characteristic features are distinctive morphologic changes of nucleus and cytoplasm, along with cleavage of chromatin at regularly spaced sites. Here we study DNA organization and nuclear structure in apoptotic thymocytes to define the cleavage event and, by implication, the role of the responsible endonuclease. We show that in apoptosis, double-stranded cleavage of DNA generates two classes of chromatin fragments: 70% of DNA exists as long, H1-rich oligonucleosomes bound to the nucleus, and 30% comprises short oligonucleosomes and mononucleosomes, which are depleted in H1, enriched in HMG1 and 2, and not attached to the nucleus. This minority class probably derives from chromatin in a transcriptionally active configuration, which would allow better access to enzymes in the nucleoplasm, producing more complete digestion. The characteristic nucleolar morphology in apoptosis can also be explained in terms of cleavage of the transcriptionally active ribosomal genes, with conservation of the nucleolin-rich fibrillar center. The chromatin cleavage, nucleolar morphologic changes, and chromatin condensation were closely mimicked by micrococcal nuclease digestion of normal thymocyte nuclei in the presence of protease inhibitors. Thus, in apoptosis, selective activation of an endogenous endonuclease appears to be responsible not only for widespread chromatin cleavage but also for the major nuclear morphologic changes.

Two new human papillomavirus types (HPV54 and 55) characterized from genital tumours illustrate the plurality of genital HPVs

The genomes of two new human papillomavirus (HPV) types, named HPV54 and HPV55, were cloned from penile lesions of 2 patients. HPV54 was isolated from a verrucous carcinoma (Buschke-Löwenstein tumour) together with full-length HPV6 genomes and HPV6 DNA molecules with a deletion of about 0.3 kb located in the non-coding region. HPV55 was isolated from a condyloma acuminatum. No cross-hybridization was observed between HPV54 DNA and the DNAs of the known cutaneous and genital HPVs by blot hybridization experiments performed under stringent conditions. In contrast, significant cross-hybridization was detected between HPV55 DNA and the DNA of HPV13, associated with benign oral lesions, and, to a lesser extent, with the DNAs of HPV6, 11, and 44, associated with benign genital proliferative lesions. The DNA sequence homology between HPV55 and HPV6, 11, and 13 was estimated at 12%, 12%, and 20%, respectively, by hybridization in liquid phase at saturation, followed by nuclease S1 analysis. The physical maps of HPV54 and 55 were aligned with the genetic maps of HPV16 and 11, respectively, by heteroduplex mapping and partial DNA sequencing. HPV54 is thus only weakly related to the known HPVs, while HPV55 represents an additional HPV6-related HPV type. HPV54 and HPV55 are uncommon genital HPV types since, in a survey of a large series of specimens of benign, pre-malignant or malignant anogenital and orolaryngeal tumours, HPV54 was not detected, and HPV55 was found in another case of condyloma acuminatum.

HPV 16-positive bowenoid papulosis and squamous-cell carcinoma of the anus in an HIV-positive man

A homosexual man in stage IV of HIV infection, who suffers from HPV 16-positive bowenoid papulosis of the anal region, is described. In one area the patient developed an HPV 16-positive squamous-cell carcinoma of the anus. Bowenoid papulosis represents a squamous-cell carcinoma in situ, and usually follows a benign clinical course. The possibility exists that immunocompromised individuals are at higher risk to develop cancer on the basis of bowenoid papulosis.

Human papillomavirus infection and anal cancer

To study the association of human papillomavirus (HPV) infection with anal cancer, we examined tissue specimens from 126 patients with malignant lesions of the anal skin or mucosa. The patients were enrolled in a population-based, case-control study of ano-rectal cancer which is being conducted in the state of Washington and the Province of British Columbia. Histologic sections from formalin-fixed, paraffin-embedded tissues were tested for the presence of HPV DNA by in situ hybridization with biotin-labelled HPV 6, 11, 16, 18 and 31 DNA probes. HPV DNA sequences were found in tumor tissues from 24 of the 126 subjects (19.0%). When only squamous neoplasms are considered, 23 of 70 subjects (32.9%) had lesions which contained detectable HPV DNA. One HPV-positive patient had a cloacogenic carcinoma that contained regions of squamous differentiation and it was in these squamous cells that HPV DNA was localized. Of the 23 squamous lesions that harbored detectable HPV DNA, 8 contained HPV 6, 10 contained HPV 16, 1 contained HPV 18 and 4 contained an unclassified virus type(s). HPV DNA was found in tissues from 14 patients with carcinoma-in situ and 10 subjects with invasive carcinoma. These results demonstrate that some malignant tumors of the anus, in both men and women, are associated with HPV infection. We conclude that the anal squamous epithelium is another site where infection with the common genital tract HPVs may carry a risk of malignant transformation.

Cloning and partial DNA sequencing of two new human papillomavirus types associated with condylomas and low-grade cervical neoplasia

Using low-stringency Southern blot analysis and cloning in lambda bacteriophage, two new human papillomavirus types (HPV-43 and HPV-44) were identified and their DNAs were cloned from vulvar tissues. The isolates were characterized by restriction endonuclease mapping and shown to be new HPV types on the basis of their minimal hybridization with all other known HPV types at high stringency. Both HPVs are most closely related to types 6, 11, and 13. HPV-43 did not exhibit any cross-reactivity with these HPV types at high stringency. HPV-44 showed minimal cross-reactivity to HPV-13, which was in the range of 20 to 25% according to liquid hybridization analysis. The deduced genomic organization of each of the two new HPVs was colinear with HPV-6b. Prevalence studies revealed that HPV-43 and HPV-44 together were found in 6 of 439 normal cervical tissues, in 8 of 195 cervical intraepithelial neoplasms, but in none of 56 cervical cancers tested thus far.

Human papillomaviruses: are we ready to type?

The issue of determining which human papillomavirus (HPV) is present in a clinical specimen (typing specimens for HPVs) is receiving attention because HPVs cause condyloma acuminata and are associated with the continuum of disease which ranges from dysplasia to invasive genital cancer. Morphological inspection of precancerous lesions is not sufficient to determine which lesions will progress and which will not. A number of research tools based primarily on deoxyribonucleic acid hybridization have been developed. These permit identification and typing of HPV in genital tract scrapings or biopsies. Some HPV types (e.g., HPV-16 and HPV-18) have been identified in high-grade dysplasias and carcinomas more commonly than other types (e.g., HPV-6) and have been designated "high risk" types for cervical cancer. Thus, the question arises whether HPV typing would improve patient management by providing increased sensitivity for detection of patients at risk or by providing a prognostic indicator. In this review, the available typing methods are reviewed from the standpoint of their sensitivity, specificity, and ease of application to large-scale screening programs. Data implicating HPVs in the genesis of genital tract cancers are reviewed, as is the association of specific HPV types with specific outcomes. We conclude that there is currently no simple, inexpensive assay for HPV types, although such assays may be developed in the future. Analysis of the typing data indicates that, while HPV types can be designated high risk and low risk, these designations are not absolute and thus the low-risk group should not be ignored. In addition, interpretation of the data is complicated by finding high-risk types in individuals with no indication of disease. Insufficient data exist to indicate whether knowledge of the presence of a given HPV type is a better prognostic indicator than cytological or histological results. Thus, more research is needed before it can be determined whether typing information will augment the method currently in use for deciding treatment regimen and whether it warrants widespread use.

Sandwich hybridization in solution: a rapid method to screen HPV 16 DNA in cervical scrapes

A solution hybridization method is introduced as a rapid diagnostic method for demonstration of papillomavirus DNA in cervical scrapes. 32P-Labelled detector probe and the biotinylated capture probes were hybridized with DNA of the specimen after pretreatment by boiling in alkaline SDS. After 4 h of hybridization the hybrids were collected onto avidin coated beads and measured. The sensitivity of the method was 1-5 x 10(5) HPV 16 DNA molecules. Cervical carcinoma cell lines CaSki and SiHa were informative as to the sensitivity of the solution hybridization and the in situ hybridization methods. CaSki cells containing about 700 HPV 16 DNA copies per cell were positive by both methods. SiHa cells with one HPV 16 DNA copy per cell were positive by the sandwich assay but remained negative in the in situ test. A series of 126 cervical scrapes collected from consecutive patients participating in a follow-up study for cervical HPV infection were tested for HPV 16 DNA by both methods. The detection rate of the sandwich test was 19/126 (15%) and that of the in situ method 21/126 (17%) yielding 26 diagnoses altogether. Twelve of these were obtained by one method only. The results obtained by studying the cervical cell lines and repeated specimens taken from constantly HPV 16 positive patients suggested that the two methods can measure different types of infections and thus complement each other in the diagnosis of cervical HPV infections.

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.