Human papillomavirus (HPV) type as an important determinant of the natural history of HPV infections in uterine cervix

A transcriptomic analysis of malignant transformation of human embryonic esophageal epithelial cells by HPV18 E6E7

Background

Esophageal cancer is one of the most common malignant tumours in humans. A series of esophageal cancer cell lines are accompanied by human papilloma virus (HPV) infection, but the mechanism behind HPV in cancer malignancy is not clear.

Methods

This research was conducted in different generations of HPV E6E7 gene-induced human foetal esophageal epithelial immortalised cells (Shantou Human Embryonic Esophageal Epithelial cell line; SHEE); the RNA sequencing transcriptomic analysis was performed to explore the mechanism of HPV infection in these cell lines.

Results

The results showed that there are 9,990 differential genes in late-stage cells compared with HPV18 E6E7-infected early foetal esophageal epithelial immortalised cells. Among these, 4,882 genes are upregulated, and 5,108 genes are downregulated. We used bioinformatics to analyze the expression and function of aberrantly expressed lncRNA, miRNA, mRNA and construct the competing endogenous RNA (ceRNA) network and protein protein interaction (PPI) network.

Conclusions

we predicted TP53TG1 promotes to malignant transformation of SHEEs by acting as a ceRNA to competitively bind to miR-6835 and regulate IGF2 expression. We also predicted IL6 serve as prognostic biomarkers and therapy target. With these results maybe provides new insights into the mechanisms of HPV carcinogenesis in esophageal cancer.

Natural history of high-grade cervical intraepithelial neoplasia: a review of prognostic biomarkers

The natural history of high-grade cervical intraepithelial neoplasia (CIN) is largely unpredictable and current histopathological examination is unable to differentiate between lesions that will regress and those that will not. Therefore, most high-grade lesions are currently treated by surgical excision, leading to overtreatment and unnecessary complications. Prognostic biomarkers may differentiate between lesions that will regress and those that will not, making individualized treatment of high-grade CIN possible. This review identifies several promising prognostic biomarkers. These biomarkers include viral genotype and viral DNA methylation (viral factors), human leukocyte antigen-subtypes, markers of lymphoproliferative response, telomerase amplification and human papillomavirus-induced epigenetic effects (host factors) and Ki-67, p53 and pRb (cellular factors). All identified biomarkers were evaluated according to their role in the natural history of high-grade CIN and according to established criteria for evaluation of biomarkers (prospective-specimen-collection, retrospective-blinded-evaluation [PROBE] criteria). None of the biomarkers meets the PROBE criteria for clinical applicability and more research on prognostic biomarkers in high-grade CIN is necessary.

Detection and typing of human papillomavirus in biopsy and cytological specimens by polymerase chain reaction and restriction enzyme analysis: a method suitable for semiautomation

Screening for high-risk human papillomavirus (HPV) types allows the detection of women at a high risk of cervical squamous carcinomas, thereby defining a subset of patients targeted for more intensive screening and follow-up. Thirty-four cervical biopsy specimens and isolated cells from cervical smears of normal women or women diagnosed with high-grade intraepithelial lesion (HGSIL) were screened for the presence of HPV by in situ hybridization (ISH) and/or by polymerase chain reaction (PCR). The exact HPV type was determined using a novel restriction typing method. The detection of HPV was facilitated greatly by the use of a PCR-enzyme-linked immunosorbent assay (ELISA)-based method. HPV was detected by PCR in 32% of the biopsy specimens, whereas only 23% had a positive staining by ISH. In one case, a double infection was detected by ISH as well as by PCR. In two cases, the presence of HPV was detected by both methods but the exact type was different. Analyzing cells isolated from cervical smears by the PCR-ELISA technique or by PCR followed by agarose gel electrophoresis, HPV was detected only in patients with HGSIL and not in the control group. The PCR system is more sensitive than conventional ISH, and the PCR-ELISA system presented in this study is efficient in screening large series of cytological samples. Furthermore, this system allows exact HPV typing on the microtiter plate. These innovations may allow the application of HPV detection and typing as a routine screening method to identify patients with a high risk of developing cervical neoplasia.

Differentiation ability and oncogenic potential of HPV-33- and HPV-33 + ras-transfected keratinocytes

Five HPV-33-immortalized and 5 HPV-33 + ras-transfected cell lines were characterized in terms of growth in soft agar, tumorigenic potential in nude mice, p21 expression, morphology and expression of differentiation markers in organotypic cultures. No striking differences were observed between the HPV-33-immortalized cell lines and their corresponding ras-transfected counterparts as regards their tumorigenicity in nude mice (only one cell line was able to develop tumors in nude mice) or their behavior on lifted collagen gels. However, all the ras-transfected cell lines gave rise to colonies in soft agar while only 2 HPV-33-transfected lines (CK1 and CK4) displayed this property. The 10 cell lines could be divided into 2 groups with respect to their phenotype in monolayer and in organotypic cultures. Lines from group I (CK2, 3, 5 and their ras-transfected homologous lines) shared a typical epithelial phenotype in monolayer and the ability (a) to form an epithelium similar to a CIN-III lesion and (b) to strongly express keratins K1-K10 and involucrin in organotypic cultures. On the other hand, for the lines from group II (CK1, CK4, CK1EJ7 and CK4EJ5), there was a correlation between an elongated phenotype in monolayer and the property (a) to form a structure similar to a microinvasive carcinoma and (b) to express vimentin and keratins K8-K18. These cell lines, exhibiting various transformation-associated alterations, can be considered as an in vitro model representing various stages of HPV-33-associated cervical carcinogenesis.

Behavior of cervical intraepithelial neoplasia (CIN) associated with various human papillomavirus (HPV) types

201 cervical punch biopsies which showed CIN lesions and were obtained between 1967 to 1977 from Falu Hospital patients, with long-term follow-up data were examined histologically and by DNA typing for human papillomavirus (HPV). We used in situ hybridization for HPV types 6, 11, 16, 18, 31 and 33 and related our findings to the behaviour of the lesion (103 regressed spontaneously and 98 progressed, some of them to invasive cervical carcinoma). There was evidence of HPV infection in 75.6% (152/201) of these lesions on histological examination, and in 53.2% (107/201) on in situ DNA hybridization. Lesions positive for HPV by both methods occurred in the younger age group (Pearson's correlation coefficient, P = 0.008). HPV 16 was found in 51/152 (33.6%) of the HPV lesions, HPV in 12.5%, and HPV 33 in 8.5% HPV 16 was highly significantly (P = 0.0001), and HPV 18 and HPV 33 were significantly (P = 0.008 and P = 0.007, respectively) associated with increasing grades of CIN. Progression to invasive carcinoma was directly (and regression inversely) correlated with the severity of CIN in the first biopsy (P = 0.005). Almost 74% (17/23) of the HPV-CIN III lesions progressed, while only 25% of the HPV-NCIN lesions (6/24) did so. The progression rate was 84.6% for HPV 33 lesions and 52.9% for HPV 16. On the other hand, progression was less common with HPV 6 (25%), and HPV 31 (30.0%). Histological grade and HPV type appear to be of value as prognostic indices.

Squamous cell cancer of the cervix, immune senescence and HPV: is cervical cancer an age-related neoplasm?

Relationships between cancer and aging will assume greater scientific importance over the coming decades as the number and proportion of elderly increase. Contrary to popular belief, cervical cancer remains an important disease into old age. This paper will briefly review what is known about immune senescence, cervical cancer and immune function, and the relationship between human papilloma virus and immunity, to support the hypothesis that these factors may contribute to the continued occurrence of invasive cervical cancer in the elderly.

Towards vaccines against human papillomavirus type-16 genital infections

Human papillomavirus type-16 (HPV-16) is strongly associated with cervical carcinoma and cervical intraepithelial neoplasia. It may soon be possible to develop prophylactic vaccines designed to induce neutralizing antibodies to HPV-16 virions in genital secretions and therapeutic vaccines to induce cytotoxic T-cell responses against HPV-16 early proteins in cervical intraepithelial neoplasia and cervical cancers. Although significant advances have been achieved, problems remain before such vaccines can be used routinely.

Cervical cancer, human papillomavirus and vaccines

HPV-16 has been strongly implicated in the aetiology of cervical cancer and pre-malignant cervical intraepithelial neoplasia. Despite current technical difficulties it may soon be possible to treat these tumours with anti-HPV-16 vaccines. A prophylactic vaccine could, in theory, be developed to induce neutralizing antibodies to HPV-16 virions in genital secretions, and a therapeutic vaccine to elicit cytotoxic T-cell responses against established lesions.

Is human papillomavirus associated with cervical neoplasia in the elderly?

There have been no studies in the United States of human papillomavirus (HPV) in elderly women. This paper presents cross-sectional data on HPV and cervical neoplasia among 232 women age 65 or more. HPV deoxyribonucleic acid (DNA) testing was performed using a modified dot-blot hybridization technique. The prevalence of HPV DNA positivity was 3.5% (95% confidence interval (CI) 0.9%, 6.0%). There were six cases of histologic cervical neoplasia. The crude odds ratio for cervical neoplasia among HPV DNA positives was 18.3 (95% CI 2.8, 120.3). The adjusted odds, controlling for age, prior screening history, current sexual activity, and past contraception use, were 12.2 (95% CI 1.2, 122.9). Ever having had a Papanicolaou smear was protective, and there was a trend for the odds of having neoplasia to increase with age. Additional studies with larger samples of elderly women are needed. If confirmed, the results suggest that, independent of past screening, HPV may increase the risk of having cervical neoplasia for elderly women.

Comparison of four in situ hybridization methods, based on digoxigenin- and biotin-labelled probes, in detecting HPV DNA in male condylomata acuminata

We have compared the efficacy of digoxigenin- and biotin-labelled probes in detecting HPV DNA by in situ hybridization on paraffin-embedded tissue sections of 57 male condyloma-suspect genital lesions. Each biopsy was hybridized with at least three of the following four methods: digoxigenin-labelled HPV DNA probes (Dig-HPV), biotinylated HPV-DNA probes (Bio-HPV), and two commercial methods (ViraType in situ and PathoGene), both based on biotinylated DNA probes. The hybridization products were visualized with colourigenic enzyme substrates. In most biopsies, the 4 methods gave equal results although cross-hybridization was most often found with the low-stringency ViraType method. Dig-HPV 6/11 probes gave positive results about twice as often as either of the commercial methods. No such difference, however, was found for HPV 16/18 probes. DNA of any type of HPV 6/11, 16/18 or 31/33/35 or 51 was detected in 28/43 (65%) of lesions showing condyloma acuminatum histology but in none of the 14 biopsies with no histological signs of HPV infection. In HPV-positive condylomata with no cellular atypia. HPV 6/11 was detected in 87% (13/15), and HPV 16/18 in 27% (4/15). In biopsies with cellular atypia, HPV types 6/11 were detected in 62% (8/13), HPV types 16/18 in 46% (6/13), and HPV types 31/33/35 or 51 in 50% (6/12). In about 50% of the biopsies where at least one hybridization method gave a positive result, either one of the commercial methods gave a negative result.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of antibodies to a linear epitope on the major coat protein (L1) of human papillomavirus type-16 (HPV-16) in sera from patients with cervical intraepithelial neoplasia and children

Antibodies to the major (L1) coat protein of human papillomavirus type 16 (HPV-16) in sera from patients with cervical intra-epithelial neoplasia (CIN) have been investigated by means of recombinant proteins and synthetic peptides. When L1-HPV-16 fusion proteins were used in immunoblot assays, no antibody reactivity was found in sera from 52 patients with CIN or from 21 unrelated children. Amino-acid sequence analyses indicated that L1-HPV-16 amino acids 473 to 492 may contain an HPV-16 type-restricted epitope since the greatest diversity occurs in this region. In the ELISA, seropositivity to peptides 473 to 492 was more common among CIN patients whose biopsies contained HPV-16 DNA (91%, 21 of 23) than among their children (24%, 5 of 21; p less than 0.001) or other CIN patients with HPV-16 DNA-negative biopsies (66%, 19 of 29; p less than 0.05), but was unrelated to the severity of the CIN lesion. Antibodies to L1-HPV-16 peptide 473 to 492 among seropositive CIN patients cross-reacted with the analogous L1-HPV-33, but not with the L1-HPV-6b peptide, and were predominantly IgM. In contrast, antibodies which recognized a less variable region of L1-HPV-16 (amino acids 279 to 293) showed no association with HPV-16 DNA status. Seropositivity to the L1-HPV-6b (amino acids 473-492) was less frequent (33%) among CIN patients and unassociated with HPV-16 DNA status (p greater than 0.1); however 51% (37 of 72) of patients with genital warts had antibodies to this peptide.

Prospective follow-up of genital HPV infections: survival analysis of the HPV typing data

A series of 532 women with genital HPV infections has been prospectively followed-up without treatment since 1981 for a mean of 50 (+/-21) months. The patients were examined at six month intervals by colposcopy, PAP smears and/or biopsy. HPV typing of all biopsies was completed using in situ, Southern blot and/or sandwich hybridization with DNA probes for types 6, 11, 16, 18, 31 and 33. Survival data analysis was applied to analyse the clinical course (i.e. spontaneous regression and progression) of the HPV lesions stratified by their HPV type, currently available for 458 women. Clinical progression was significantly related to the HPV type present in the lesions. The progression rate was 11.1% (6/54) for HPV 6 lesions, 14.3% (8/56) for HPV 11, 35.2% (32/91) for HPV 16, 12.5% (4/32) for HPV 18, 18.8% (6/32) for HPV 31, 19.4% (6/31) for HPV 33 and 28.6% (4/14) for doubly infected lesions. The lowest progression rate, 6.1% (9/148), was found in lesions which remained constantly HPV DNA-negative. In the survival analysis the probability of progression varied significantly between the six HPV types (p = 0.0005, overall). After grouping the viral types as HPV 6/11 ('low risk'), HPV 16/18 ('high risk') and HPV 31/33 ('intermediate risk') the overall probability of progression remained significantly different (p = 0.0035, overall). In clinical regression, however, the HPV type was not an equally good predictor (p = 0.1952, overall). Within groups HPV 6/11, 16/18 and 31/33 the differences were even less significant (p = 0.4759, overall). In the pairwise comparison significant differences in progression occurred when HPV type 16 was compared to HPV 6, HPV 11 or HPV DNA-negative lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Prospective follow-up of cervical HPV infections: life table analysis of histopathological, cytological and colposcopic data

A total of 532 women with established cervical HPV infection have been prospectively followed (without treatment) since 1981 for a mean of 45 (SD 21) months. The patients were examined by colposcopy, PAP smears and/or punch biopsy every 6 months. The life-table method was applied to analyze the clinical course (i.e. regression and progression) of the HPV lesions, stratified by their colposcopic pattern, PAP smear findings and grade of CIN. During the follow-up, 107 (41.8%) of 256 patients with HPV-NCIN lesion in the first punch biopsy, experienced spontaneous regression. The corresponding proportions for HPV-CIN I, HPV-CIN II and HPV-CIN III lesions were 31.1%, 34.2%, and 20.7%, respectively. In the overall comparison between these four groups, the heterogeneity in the probability of regression was statistically significant (p = 0.0005). Clinical progression was also associated significantly with the histological grade of the lesions in the first biopsy. Progression rate was only 5.8% for HPV-NCIN lesions, as compared to 12.3% for HPV-CIN I, 20% for HPV-CIN II, and 55.2% for HPV-CIN III. The probability of progression varied significantly between the four groups (p less than 0.00001). Cumulative proportion of regression was 46% for patients with PAP smear class I, 84% with class II, and 82% for those with class III, cells, i.e. PAP smear was not of value in predicting the regression. However, PAP smears predicted clinical progression (p = 0.006 overall).(ABSTRACT TRUNCATED AT 250 WORDS)

Immortalization of human foreskin keratinocytes by various human papillomavirus DNAs corresponds to their association with cervical carcinoma

Normal human foreskin keratinocytes cotransfected with the neomycin resistance gene and recombinant human papillomavirus (HPV) DNAs (types 16, 18, 31, and 33) that have a high or moderate association with cervical malignancy acquired immortality and contained integrated and transcriptionally active viral genomes. Only transcripts from the intact E6 and E7 genes were detected in at least one cell line, suggesting that one or both of these genes are responsible for immortalization. Recombinant HPV DNAs with low or no oncogenic potential for cervical cancer (HPV1a, -5, -6b, and -11) induced small G418-resistant colonies that senesced as did the nontransfected cells. These colonies contained only episomal virus DNA; therefore, integration of HPV sequences is important for immortalization of keratinocytes. This study suggests that the virus-encoded immortalization function contributes to the pathogenesis of cervical carcinoma.

Factors associated with progression of cervical human papillomavirus (HPV) infections into carcinoma in situ during a long-term prospective follow-up

In the course of a prospective study of 508 women with papillomavirus (HPV) lesions of the uterine cervix, 66 lesions that progressed into carcinoma in situ (CIS) were identified and treated by conization during a mean follow-up period of 35 months. The lesions were investigated with light microscopy and with in-situ DNA hybridization using 35S-labelled probes for HPV 6, 11, 16, 18, 31 and 33. After radical cone treatment, 11 of the 66 women (16.7%) have presented with a recurrent HPV infection. The recurrence rate increased with the duration of the follow-up period from less than 10% at the mean follow-up of 25 months to 16.7% at the most recent follow-up at 35 months. Most of these 66 HPV lesions (89%) presented with concomitant CIN in the first punch biopsy, but it is noteworthy that the other 11% presented without concomitant CIN. HPV DNA of at least one of the six types examined was found in 73% of the first biopsies and it is noteworthy that the so-called 'low-risk' types, HPV 6 and 11, were found as frequently as the 'high-risk' types, HPV 16 and 18 (18% and 17%, respectively). This would suggest a similarity in the biological behaviour of these two HPV groups. Although the concept of the 'high-risk' and 'low-risk' HPV types may remain at least partially valid, it is imperative to realize that infection by HPV 6 and 11 by no means excludes the possibility for clinical progression into CIS and eventually to an invasive carcinoma.

Screening of premalignant cervical lesions for HPV 16 DNA by sandwich and in situ hybridization techniques

A series of 97 cervical smears and 69 directed punch biopsies derived from 84 consecutive women prospectively followed-up for cervical HPV (human papillomavirus) infections were studied using the sandwich hybridization and in situ hybridization techniques with HPV 16 DNA probes. The aim was to test the sensitivity and applicability of these two techniques in routine diagnosis of cervical HPV infections from smears. As a measure of specimen adequacy, the number of cells recovered in the cervical scrape was determined along with HPV 16 DNA in the sandwich hybridization test using human pro-alpha 2(I)-collagen gene probe. CIN (cervical intraepithelial neoplasia) was suggested in 56% of the patients by the Pap smear, and disclosed in 65% of the biopsies. HPV 16 DNA was present in 57% of cervical scrapes consistent with CIN, i.e., were of Pap smear classes III or IV. Forty percent of the scrapes not suggestive of CIN, i.e., Pap smear classes I or II, also contained HPV 16 DNA. The detection rate for HPV 16 DNA of the sandwich hybridization method was 89% of that of the in situ method in adequate scrapes, but only 43% in cell-poor specimens. The number of HPV 16 DNA-positive scrapes as compared with the total number of diagnoses obtained by studying also the biopsies was 31/36 (69 patients). The results indicate that the cervical scrape as a noninvasive specimen is applicable for screening of cervical HPV infections, and it can be studied with acceptable sensitivity by the rapid sandwich hybridization technique. However, if a punch biopsy is indicated it should be studied using the in situ hybridization technique that allows more sensitive detection of HPV DNA than any other hybridization method and enables the analysis of several HPV types in the same sample instead of only one HPV type in the scrapes.

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.

Nucleic acid sandwich hybridization in detection of HPV 16 DNA: technique and its clinical application

Nucleic acid sandwich hybridization technique was used for detection of HPV 16 specific DNA in cervical scrapes. Alternating HPV 16-PstI fragments were cloned into plasmid pBR322 and phage M13mp10. pBR322-clones were used as 32P-labelled probe reagents and the M13mp10 clones as catching reagents in the assay. The detection limit of the test proved to be 1-5 X 10(5) HPV 16 molecules per test. A weak cross reaction was seen with HPV 31 DNA but not with the other types tested, e.g. HPV 6, 11, 18 and 33. Cervical scrapings obtained from 163 consecutive patients included in a prospective follow up study were analyzed for HPV 16 DNA with the sandwich hybridization method, dot-blot hybridization being used as a reference method. Sandwich hybridization assay detected 25 positive cases out of 163 specimens (15.3%). Of these 6 and 3 additional specimens were positive in dot-blot hybridization assay. HPV 16 DNA was related to higher PAP grades, and HPV 16 appeared more frequently in HPV CIN than HPV NCIN lesions. None of the infections caused by HPV 16 regressed, and 24% progressed during the follow up.

Cytologic and histologic manifestations of human papillomavirus infection of the female genital tract and their clinical significance

The historical developments in the recognition of the role of human papillomavirus (HPV) infection in cells and tissues of the female genital tract are briefly summarized. The identification of a specific marker cell, the koilocyte, has led to initial studies of frequency and biologic significance of neoplastic lesions of the uterine cervix associated with HPV. By molecular virology techniques, over 40 types of HPV have been identified and their tissue affinity determined. Types 6, 11, 16, 18, and 31 are most commonly associated with anogenital lesions, among them a broad spectrum of cervical intraepithelial neoplasia (CIN). While current evidence suggests that lesions associated with HPV Types 6 and 11 are potentially less harmful to the patient than lesions associated with HPV Types 16 and 18 (which have been identified also in invasive cervical carcinomas and cell lines derived therefrom), a major long term prospective study may be required to confirm this view. A factor that complicates the issue still further is the recent observation that HPV DNA of all four types has been identified in 11% of women and 5.5% of men free of disease. Infection with multiple viral types (including Types 16 and 18) was common in this apparently healthy population. Although HPV must be considered as a prime candidate for a transforming virus, current evidence suggests that the infection with the virus is per se an insufficient condition for the development of precancerous lesions or cancer of the uterine cervix and that another factor or factors may be necessary for these events to take place. Some of these possible cofactors such as age, repeated infections, and the immune status of the patient are discussed. A great deal of additional work is required before the precise role of HPV virus in the genesis of carcinoma of the uterine cervix, vulva, and vagina is firmly documented.

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.

Detection of human papillomavirus DNA by the nucleic acid sandwich hybridization method from cervical scraping

Cervical scrapes collected from 100 consecutive patients participating in a prospective follow-up study for cervical human papillomavirus (HPV) infections were tested for the presence of HPV 11 DNA by the nucleic acid sandwich hybridization method, which allows testing the specimens in a crude form. Part of each specimen was processed through phenol extraction and DNA purification to a dot blot hybridization assay. The dot blots were serially hybridized with HPV 6, 11, 16, and 18 probes as well as with an Alu-repeat probe to estimate the number of cells in the specimen. In PAP smears, HPV-infection was suspected in 63 patients whereas in 37 patients the smear was negative. In the first group, the dot blot assay revealed three cases of HPV 11, two of HPV 16, and one of HPV 18 infection. In the second group with normal PAP smear, one additional HPV 18 infection was found. The sandwich hybridization assay detected 5 HPV 11 infections, including the three mentioned above. All HPV DNA-positive samples contained at least 1.6 X 10(6) cells. Since we considered this a prerequisite for successful diagnosis, only 25 specimens in the first group and 15 in the second were adequate specimens. Thus the HPV-DNA detection rate was 32% (8/25) in the first group and 1/15 in the second. This study demonstrates that sandwich hybridization, detecting 1-3 X 10(5) HPV 11 molecules is a reliable diagnostic method. Cervical scrape is a valuable alternative to punch biopsy, but the number of cells collected is critical for the outcome of the assay.

An improved in situ DNA hybridization protocol for detection of human papillomavirus (HPV) DNA sequences in paraffin-embedded biopsies

In situ DNA hybridization is becoming rapidly an important technique for detection and typing of human papillomaviruses (HPV) in epithelial lesions, some of which (those due to HPV 16, 18 and 31) seem to possess an increased risk for progression into an invasive squamous cell carcinoma. An improved in situ DNA hybridization technique (Technique II) was described, and the results obtained in a series of cervical and penile HPV lesions were compared with those given by the in situ hybridization technique (Technique I) previously used in our laboratory. Special emphasis was made to increase the sensitivity with three basic alterations of the hybridization protocol; omission of the 0.2 N HCl wash, use of increased proteinase K concentration (from 50 micrograms/ml to 1 mg/ml), and elevated denaturation temperature (obtained by a heating block instead of an incubator). Poly-D-lysine as a slide-coating medium was replaced by Kodak Photo-Flo 200 to improve the attachment of the tissue sections on the slides. Identical HPV DNA types were discovered by the two hybridization techniques. The attachment of the tissue sections was equal on the slides coated with either poly-D-lysine or Kodak Photo-Flo 200, and the latter did not interfere with the sensitivity of in situ hybridization. The hybridization signals for HPV DNA were weak or moderate in 15/16 lesions with Technique I, but intense in 10/16 lesions with Technique II (P less than 0.001). Furthermore, the resolution of Technique II seemed to be superior to that of Technique I, while being capable of disclosing HPV DNA in the intermediate cell layers (P less than 0.001) and in basal/parabasal cell layers (P less than 0.025) of both the cervical and penile lesions. The discovery of HPV DNA in the parabasal cells provides important clues to the understanding of the biology of HPV infection in the squamous epithelium, and makes this improved in situ DNA hybridization technique invaluable in assessing the lesions, where low copy numbers of HPV are to be expected.

Human papillomavirus (HPV) DNA sequences demonstrated by in situ DNA hybridization in serial paraffin-embedded cervical biopsies

An in situ DNA hybridization technique was used to identify various types of Human papillomavirus (HPV) in paraffin sections of serial punch biopsies taken from 64 patients having colposcopy because of abnormal smears. There women were in fact 64 consecutive patients out of 505 attending our clinic (at 6-month intervals) since 1981 for HPV infections. HPV 6 DNA sequences were found in 20%, HPV 11 in 17%, HPV 16 in 8% and HPV 18 in 5% of the 64 biopsies analysed with this method so far. More than 60% of HPV 6-positive lesions belong to HPV-NCIN (HPV lesion without concomitant CIN) or HPV-CIN I categories, as contrasted with HPV 16-positive lesions, 80% of which belong to HPV-CIN II and III categories. None of the HPV 16- or HPV 18-infected lesions regressed, as contrasted with 23% and 45% in those infected with HPV 6 and HPV 11, respectively (P less than 0.01). The rate of progression (38.4% and 45.5%, respectively) was markedly lower in HPV 6- and HPV 11 lesions as compared with that (80%) of HPV 16 lesions. The present results while supporting the concept on HPV 16 and HPV 18 as the high risk HPV types in cervical carcinogenesis also emphasize the applicability of the in situ DNA hybridization as a powerful tool in analysis of the specific HPV DNA sequences in routinely progressed biopsies of these lesions.