Presence and expression of human papillomavirus sequences in human cervical carcinoma cell lines.

A series of human carcinoma cell lines was examined for human papillomavirus (HPV) DNA sequences with the use of HPV-6, HPV-11, HPV-16, and HPV-18 DNA probes. Six of eight cell lines derived from human cervical carcinomas were shown to contain integrated HPV DNA sequences. In five of these six lines, HPV-specific polyadenylated RNA species could also be identified. The expression of HPV sequences was detected in three lines with a HPV-18 DNA probe and in two lines with a HPV-16 DNA probe. Of the two lines which contained HPV-16 specific RNA, one contained HPV DNA sequences which hybridized only to an HPV-16 probe, and the other contained HPV DNA sequences which hybridized to both HPV-16 and HPV-18 DNA probes. Six cell lines established from human squamous-cell carcinomas of the bladder, pharynx, lung, esophagus, and vulva were negative for HPV-6, HPV-11, HPV-16, and HPV-18 DNA sequences under stringent hybridization conditions.     

Penile/anal condylomas and squamous cell cancer

Summary Acuminate condylomas from the penis (n=17) and anus (six cases), three anal/penile giant condylomas, anal Bowen's disease (four cases), and intraanal squamous cell carcinomas with associated condylomatous changes (10 cases) including two verrucous carcinoma were studied for human papillomavirus (HPV) infections with nick translated, biotinylated cDNA probes for HPV 6, 11, 16 and 18. In addition, six cases of flat white penile lesions designated as lichen sclerosus et atrophicus were examined.Reannealed complementary DNA strands were detected in situ with either immunoenzyme or immunogold protocols.The in situ hybridizations resulted in 1/6 positive penile lichenoid lesions, 12/17 positive penile acuminate condylomas, 6/6 positive anal acuminate condylomas (including two condylomas with cellular atypias), 2/3 positive giant condylomas, 1/4 positive anal bowenoid lesions, and 4/10 positive keratinized squamous cell carcinomas, two of them being verrucous carcinomas. All penile/anal condylomas and two giant condylomas harboured HPV 6 and/or 11 DNA.The five positive carcinomas (carcinoma in situ/invasive cancer) contained HPV 6 and/or 11 in two cases (including the verrucous carcinomas), and HPV 16 and/or 18 in three cases (one carcinoma in situ, two invasive carcinomas).Recurrent malignancies were seen in one case to harbour the same HPV type as the primary lesions (HPV 16). In one particular patient, a double infection with HPV 16 and HPV 18 was demonstrated in distantly located malignant tumours. Our study confirms the restrictions and the value of non-isotopic hybridization methods applied to archival tissues, and extends the knowledge on the presence and distribution of HPV infections at anogenital sites.This study was supported by the Deutsche Forschungsgemeinschaft (Lo 285/2-4) and the Hamburger Stiftung zur Förderung der Krebsbekämpfung     

Detection of human papillomavirus DNA in squamous bronchial metaplasia and squamous cell carcinomas of the lung by in situ hybridization using biotinylated probes in paraffin-embedded specimens

We examined a series of paraffin-embedded tissue specimens from 10 cases of squamous bronchial metaplasia and 33 cases of squamous cell carcinoma of the lung for histologic characteristics and for the presence and typing of human papillomavirus (HPV) by molecular in situ hybridization with biotinylated probes types 6, 11, 16 and 18 under stringent conditions (temperature, 19 degrees C). Fourteen of these lesions (32.5%) showed typical condylomatous histologic changes. Human papillomavirus DNA was present in seven (16%) specimens. Type 6 HPV DNA was detected in one of the squamous bronchial metaplasia cases. In six of the squamous cell carcinomas cases (18%), HPV DNA was identified (type 18, three cases; type 16, one case; type 11, one case; and type 6, one case); one of the squamous cell carcinoma specimens contained both HPV types 16 and 18. Our data confirm the presence of HPV DNA in squamous metaplastic bronchial mucosa and epidermoid lung carcinoma on paraffin-embedded tissues. This suggests that an HPV infection with benign or potentially oncogenic HPV types could be associated not only with genital tumors, but also with bronchial and lung tumors. The role of HPV DNA in the process of malignancy conversion is not yet known; HPV DNA could possibly be a cocarcinogenic factor. In situ hybridization with biotinylated probes is a useful and appropriate method of retrospective analysis of HPV DNA sequences in routinely paraffin-embedded lesions. It may be used to identify patients at risk of more serious or possibly malignant progression.     

Association of human papillomavirus type 16 with neoplastic lesions of the vulva and other genital sites by in situ hybridization.

The authors examined paraffin sections from 85 genital tract tissues from 49 cases for the presence of human papillomavirus (HPV) Types 6/11, 16, and 18 by stringent in situ hybridization using 35S-labeled viral DNA probes, and for viral capsid antigen by the immunoperoxidase test. The cases, selected mostly on the basis of vulvar pathology, were distributed as follows: early neoplasia (Group I, 6 cases); early neoplasia with viral cytopathic effect (CE) (Group II, 24 cases); and papillomavirus infection (PVI) (Group III, 19 cases). Available tissues from all affected sites were examined when the disease was multicentric. One or more viral DNAs were identified in 58% of 77 tissues from Groups II and III and in 2 of 8 tissues from Group I. HPV-6/11, HPV-16 and HPV-18 DNAs were detected, respectively, in 25, 24, and 2 tissues; 3 tissues were infected simultaneously with either two or three viruses. Viral DNA was identified at more than one site in 14 of 30 DNA-positive patients; in 10 of these, a single type was detected at all sites in the same patient. The viral DNA was localized mostly in areas showing viral cytopathology. The presence of HPV-16 correlated with neoplasia. HPV-16 DNA was identified in the 2 virus-positive tissues showing neoplasia, in 17 of 20 (85%) of the DNA-positive tissues showing neoplasia with CE, and in 5 of 25 (20%) of the DNA-positive tissues showing PVI. Conversely, HPV-6/11 was found in 25% of the DNA-positive tissues showing neoplasia with CE and in 80% of the cases of PVI. An HPV genome was identified in neoplastic cells in 14 instances; in all but 1 case, the genome was HPV-16. The association of HPV-16 with neoplasia was seen for both vulvar and cervical lesions. Viral antigen was detected in 83% of lesions associated with HPV 6/11 and in 62% of lesions associated with HPV-16.     

HPV DNA in intraepithelial neoplasia and carcinoma of the vulva and penis.

Surgical specimens of 15 patients with early and 12 patients with advanced squamous cell carcinoma of the vulva and the penis were examined for the presence of human papillomavirus (HPV) type 6, 11, 16, and 18 DNA by Southern blotting (SB) and polymerase chain reaction (PCR) analysis. By SB, HPV type 16 DNA was detected in all early carcinomas and 2 of 12 cases of advanced squamous cell carcinoma (ISCC) of the vulva and penis. PCR revealed HPV DNA in four additional cases of vulvar and penile ISCC negative by SB. Three cases contained HPV16 and one HPV18. Two cases of vulvar and penile Buschke-L?wenstein (BL) tumor with malignancy and one case of vulvar verrucous carcinoma were also examined by both techniques. While BL tumors were associated with DNA of HPV6 or 11, no HPV association was found for verrucous carcinoma. Our results confirm that the detection rate of HPV DNA in early vulvar and penile carcinomas is much higher than in invasive carcinomas. In addition, we have shown that in the lower genital tract, 50% of cases of ISCC are HPV16 correlated. The absence of HPV DNA (types 6, 11, 16, and 18) in the remaining 50% of cases of ISCC thus suggests that vulvar and penile ISCC may have more than one pathogenetic pathway.     

Human papillomavirus type 6 detected by the polymerase chain reaction in invasive sinonasal papillary squamous cell carcinoma.

Eight sinonasal carcinomas (one adenocarcinoma, two undifferentiated nasopharyngeal carcinomas, and five squamous cell carcinomas) were investigated for evidence of human papillomavirus (HPV) infection using in situ hybridization and the polymerase chain reaction for HPV types 6, 11, 16, 18, and 33. All eight cases were negative for HPV infection by in situ hybridization, while a single HPV-6-positive case was identified by the polymerase chain reaction. The HPV-positive case was an invasive papillary squamous cell carcinoma of the maxillary sinus. Although HPV-6 is usually associated with benign anogenital condylomata, it has been identified in malignant lesions of the upper respiratory tract. This may reflect exposure of the upper aerodigestive tract to additional carcinogens, such as smoke and alcohol, superimposed on the background proliferative stimulus of the HPV infection.     

Detection of human papillomavirus DNA in anogenital exophytic lesions by in situ hybridization to paraffin sections

In situ hybridization was used to detect human papillomavirus (HPV) nucleic acids (type 6b, 11, 16, 18, 31, and 33) and immunohistochemistry was done to detect papillomavirus common antigen in paraffin sections of biopsy specimens. Two patients suffering from condyloma acuminatum contained HPV-6b and HPV-11. Both cases showed small foci of the antigen-positive cells. One patient having condyloma acuminatum with dysplastic features contained a small quantity of HPV-16 without any antigen-positive cells. One case of verrucous carcinoma showed neither HPV-DNA nor antigen. In situ hybridization is a powerful tool in the analysis of the pathogenesis of HPV-associated neoplasms.     

Detection of human papillomavirus in large cell neuroendocrine carcinoma of the uterine cervix: a study of 12 cases

AIM: To investigate the role of human papillomavirus (HPV) in large cell neuroendocrine carcinoma (LCNEC) of the uterine cervix. METHODS: Twelve archival, immunohistochemically and/or electron microscopically confirmed cases of cervical LCNEC were studied. Non-isotopic in situ hybridisation (NISH) was performed on the formalin fixed, paraffin wax embedded biopsies using digoxigenin labelled probes to HPV types 6, 11, 16, 18, 31, and 33. The tumours were then subjected to polymerase chain reaction (PCR) analysis using GP5+/GP6+ consensus primers to the HPV L1 gene, in addition to type specific primers to the E6 and E6/E7 genes. RESULTS: HPV-16 was detected by NISH and/or PCR in seven of the 12 carcinomas. Two additional tumours were HPV-18 positive by NISH and/or PCR. HPV DNA was not detected in the three remaining cases. CONCLUSION: Integration of high risk HPV, in particular type 16 and to a lesser extent type 18, is associated with this uncommon variant of cervical carcinoma.     

肺癌组织中人乳头瘤病毒16和18型DNA相关序列的检测

采用聚合酶链反应技术（ＰＣＲ）及用ＰＣＲ法制备生物素标记探针的斑点杂交法,检测５０例肺癌、１８例肺良性病及４例胎肺组织中高危险型人乳头瘤病毒（ＨＰＶ）１６、１８型ＤＮＡ相关序列,以探讨ＨＰＶ与肺癌之间发生的关系。结果３２％的肺癌组织中检测出ＨＰＶ１６、１８ＤＮＡ,其中ＨＰＶ１６ＤＮＡ阳性１０例,ＨＰＶ１８ＤＮＡ阳性５例,１例同时含ＨＰＶ１６、１８ＤＮＡ。２７例鳞癌组织中ＨＰＶＤＮＡ阳性率为４８．２％。而肺良性病组织及胎肺组织均未发现ＨＰＶＤＮＡ。ＨＰＶＤＮＡ呈阳性的肺癌患者绝大多数为重度吸烟者。提示原发性肺癌的发生可能与ＨＰＶ感染有关。     

Identification of genital tract papillomaviruses HPV-6 and HPV-16 in warts of the oral cavity

Warty lesions of the oral cavity were examined for etiologic association with genital tract papillomaviruses HPV-6, HPV-11, and HPV-16. DNAs extracted from ten oral biopsies were screened for HPV genomic sequences by Southern transfer hybridization with 32P-labeled viral DNA probes. Nonstringent hybridization with an HPV-6 probe revealed papillomavirus DNA sequences in four of seven tissues with histologic evidence of papillomatosis, in none of two tissues without histologic evidence of papillomatosis, and in one tissue that was not examined by histology. Stringent hybridization tests with HPV-6 and HPV-16 probes identified the genome in one tissue as being HPV-16, in a second tissue as being HPV-6 subtype a, and in a third tissue as HPV-6 (subtype unidentified); papillomavirus DNA sequences in two tissues are as yet not identified. An additional case of HPV-6 or HPV-11 related oral cavity lesion was diagnosed by in situ hybridization of paraffin sections with a 35S-labeled, mixed HPV-6 + HPV-11 probe. The hybridization in the positive section was extensive and confined to epithelial nuclei. The oral lesions associated with genital tract papillomaviruses were asymptomatic, multiple or single, and were located in different parts of the oral cavity, for example, on the gingivae, on the tongue, on the lip, on the tonsillar pillar, and on the floor of the mouth.     

Human papillomavirus type 13 and focal epithelial hyperplasia of the oral mucosa: DNA hybridization on paraffin-embedded specimens

Summary 16 cases of focal epithelial hyperplasia (Heck's disease) were studied for the presence of human papillomavirus DNA by means of nucleic acid hybridization. Hybridization was carried out in situ with biotin-labelled probes of HPV 1, 6, 11, 13, 16, and 18 DNA under stringent and non-stringent conditions. Under non-stringent conditions, 6 of 16 cases (38%) hybridized to a mixture of HPV 1, 6, 11, 16, and 18 DNA. When these probes were applied under stringent conditions, only one case could be shown to be weakly positive for HPV 6/11 DNA. Further stringent hybridizations, which were conducted with a HPV 13 probe on 12 of our 16 cases, revealed a positive result in 9 of 12 cases (75%). The results of our study strongly substantiate the concept that HPV 13 or a closely related HPV type is associated with lesions morphologically presenting as focal epithelial hyperplasia.     

用聚合酶链反应检测食管癌组织中人乳头瘤病毒DNA

应用聚合酶链反应（ＰＣＲ）技术对汕头市区６８例食管癌的石蜡包埋标本进行人乳头瘤病毒（ＨＰＶ）ＤＮＡ序列检测，结果显示，ＨＰＶＤＮＡ总阳性率为６６．１８％（４５／６８），检出型别主要为ＨＰＶ６、１１、１６，检出率分别为２７．９４％、３６．７６％和２７．９４％，经统计学处理三型间无显著性差异；ＨＰＶ－１８及未定型别各占８．８２％。值得注意的是ＨＰＶ感染中多重感染占阳性病例的５３．３３％（２４／４５）。初步结果表明，汕头市食管癌高发区有较高的ＨＰＶ感染率，此与食管癌的发生，可能有密切关系。     

Clinical and histologic features of vulvar carcinomas analyzed for human papillomavirus status: evidence that squamous cell carcinoma of the vulva has more than one etiology.

The association between the human papillomavirus (HPV) and malignant neoplasms of the uterine cervix is well established; however, its role in the pathogenesis of vulvar cancer has not been well defined. This study correlates the clinical and histopathologic features of 21 invasive carcinomas of the vulva with the presence of HPV DNA as detected by Southern blot and polymerase chain reaction (PCR) analysis. By one or both techniques, HPV DNA was detected in 10 of the 21 tumors analyzed; all HPVs containing tumors hybridized with HPV-16 probes, although PCR also detected HPV-6 in two of the HPV-16-containing tumors. No HPV-18 DNA was detected in any tumor by PCR or Southern blot hybridization. Both the invasive cancer and the surrounding intraepithelial disease tended to display histopathologic features that usually could distinguish HPV-associated cancers from those without HPV DNA. The intraepithelial lesions associated with HPV-containing tumors were of the bowenoid type with koilocytosis, while tumors lacking HPV generally demonstrated a simplex type of intraepithelial lesion. Invasive tumors with no viral DNA were more frequently keratinizing than the HPV-containing cancers. Race, parity, hormonal therapy, and alcohol use did not affect the HPV status; however, HPV DNA was more prevalent in the tumors of younger women and in those with a history of tobacco use. Human papillomavirus status had no impact on the stage of disease or its prognosis. These findings identify two subsets of vulvar carcinoma cases based on HPV hybridization data and the histopathologic characteristics of the tumor.     

Squamous papillary neoplasia of the adult upper aerodigestive tract

Selected papillary squamous tumors of the upper aerodigestive tract (UADT) mucosa in adult patients do not have well-defined histologic criteria and the clinical behavior is poorly understood. To better characterize this spectrum of neoplasms, UADT papillary neoplasms were evaluated by routine histology, determination of cellular DNA content using Feulgen-stained tissue sections, and the typing of human papillomavirus (HPV) by in situ hybridization. Solitary papillomas were studied in two patients; there was no recurrence in either case, both had normal DNA content, and one was typed as HPV-6 while the other was typed as HPV-11. Seven adult patients with recurrent papillomatosis and at least one biopsy with dysplasia/atypia were identified (mean age at diagnosis, 13.3 years; mean age at last contact, 42.7 years). Six of seven patients had abnormal DNA cellular content in foci of epithelial atypia. In all biopsies evaluated, the papillomas of the seven patients were consistently typed as either HPV-6 or HPV-11. Six patients with malignant papillary neoplasms also had abnormal DNA cellular content, but none revealed evidence of HPV type 6, 11, 16, or 18 by in situ hybridization of tissue sections. In many of the recurrent papillomas, the degree of epithelial atypia encountered was pronounced and was commonly misdiagnosed as carcinoma in situ or papillary carcinoma. The aneuploid DNA content of these foci of atypia reflected the abnormal cellular appearance and partially explained the overdiagnosis of malignancy. However, none of the seven patients were treated for malignant disease and none progressed to invasive carcinoma, with an average follow-up period of almost 30 years. We conclude that histologic and cytologic atypia in HPV-containing papillomatosis may be appreciable. The aneuploid DNA content may represent premalignant conditions and the patient may be at an increased risk for the subsequent development of squamous cancer. However, none of the seven patients with recurrent papillomatosis developed any evidence of malignancy. In addition, none of the patients with papillary carcinomas had previous recurrent papillomatosis.     

The characteristics of human papillomavirus DNA in head and neck cancers and papillomas

AIM: To determine the prevalence, type, physical state, and viral load of human papillomavirus (HPV) DNA in cases of head and neck cancer and recurrent respiratory papillomatosis (RRP). METHODS: The prevalence and type of HPV DNA was determined in 27 fresh frozen tissue specimens from patients with head and neck cancers and 16 specimens from 10 patients with RRP by MY09/MY11 and GP5+/GP6+ nested polymerase chain reaction (PCR) and subsequent restriction enzyme cleavage. The physical state of HPV DNA was analysed by E1, E2, and E1E2 specific PCRs and Southern blot hybridisation (SBH). RESULTS: HPV DNA was detected in 13 of 27 cancers and 10 of 10 papillomas. Both low risk HPV-6 and HPV-11 and high risk HPV-16 were present in cancers in low copy numbers, whereas papillomas exclusively harboured low risk HPV-6 and HPV-11. E1E2 PCRs failed to determine the physical state of HPV in cancers except one case where HPV-6 DNA was integrated. In contrast to cancers, all papillomas showed the episomal state of HPV DNA and a relatively higher viral load. CONCLUSIONS: Based on the prevalence, type, physical state, and copy number of HPV DNA, cancers and papillomas tend to show a different HPV DNA profile. The 100% positivity rate of low risk HPV types confirms the role of HPV-6 and HPV-11 in the aetiology of RRP.     

Vulvar carcinomas: search for sequences homologous to human papillomavirus and herpes simplex virus DNA

Ten cases of intraepithelial carcinoma, five with Bowenoid features and five with early invasion, and ten cases of invasive vulvar carcinoma were examined by in situ hybridization and Southern blot analysis using DNA probes for human papillomavirus (HPV) types 6, 11, 16, 18 and 31. HPV DNA was detected in 90% of the intraepithelial cases and in 10% of the invasive cases. All positive cases showed the presence of DNA of HPV type 16. The cases with intraepithelial lesions revealed a strong correlation between the presence of HPV type 16 DNA, cigarette smoking habit, other potential cofactors such as herpes simplex (HSV) DNA sequences and the use of contraceptive drugs, and clinicopathologic features of Bowen's type in situ squamous cell carcinoma. Similar associations were not observed among the cases with invasive disease. While HPV-16 is associated with differentiated Bowenoid type vulvar intraepithelial neoplasia, which appears to be the most common form of early carcinoma of the vulva, the same association was not seen with respect to advanced vulvar invasive squamous cell carcinoma.     

High frequency of human papillomavirus 6/11, 16, and 18 infections in precancerous lesions and squamous cell carcinoma of the conjunctiva in subtropical Tanzania

Dysplastic lesions and epithelial neoplasms of the conjunctiva account for approximately 2% of all malignant tumors in subtropical Tanzania. We examined the pathophysiologic role of human papillomavirus (HPV) in the development of conjunctival carcinoma in subtropical Tanzania, which has a high HPV prevalence. Tissue samples from 14 patients were obtained from the cancer registry archives at the medical center of the university in Dar es Salaam, Tanzania. A highly sensitive nonradioactive in situ hybridization technique (ImmunoMax) was applied to paraffin-embedded tissue samples to identify HPV DNA in conjunctival epithelial dysplasia and epithelial neoplasms. In each case, conventional morphologic evaluation revealed a transitional lesion extending from koilocytic dysplasia to severe dysplasia or invasive squamous cell carcinoma. Highly specific, morphologically easily distinguishable labeling of HPV-6/11, HPV-16, and HPV-18 was found in most cases. Coinfections were observed frequently. The signals showed varying intensities and different patterns of distribution. In general, higher signal intensity was found in dysplasia grades 1 and 2 and in well-differentiated areas of the invasive component of conjunctival carcinoma compared with less differentiated areas. This observation underlines the central role of HPV-16 and HPV-18 in the oncogenesis of conjunctival cancers in subtropical Tanzania.     

Detection and typing of human papillomavirus DNA in penile carcinoma: evidence for multiple independent pathways of penile carcinogenesis

To clarify the role of human papillomavirus (HPV) in penile cancer we evaluated the prevalence of HPV DNA in different histological subtypes of penile carcinoma, dysplasia, and condyloma using a novel, sensitive SPF10 HPV polymerase chain reaction assay and a novel genotyping line probe assay, allowing simultaneous identification of 25 different HPV types. Formalin-fixed, paraffin-embedded tissue samples were collected from the United States and Paraguay. HPV DNA was detected in 42% cases of penile carcinoma, 90% cases of dysplasia, and 100% cases of condyloma. There were significant differences in HPV prevalence in different histological cancer subtypes. Although keratinizing squamous cell carcinoma and verrucous carcinoma were positive for HPV DNA in only 34.9 and 33.3% of cases, respectively, HPV DNA was detected in 80% of basaloid and 100% of warty tumor subtypes. There was no significant difference in HPV prevalence between cases from Paraguay and the United States. In conclusion, the overall prevalence of HPV DNA in penile carcinoma (42%) is lower than that in cervical carcinoma (approximately 100%) and similar to vulvar carcinoma (approximately 50%). In addition, specific histological subtypes of penile cancer--basaloid and warty--are consistently associated with HPV, however, only a subset of keratinizing and verrucous penile carcinomas is positive for HPV DNA, and thus these two tumor groups seem to develop along different pathogenetic pathways.     

In situ DNA hybridization of cervical small cell carcinoma and adenocarcinoma using biotin-labeled human Papillomavirus probes.

A preferential association of human Papillomavirus (HPV) type 18 with cervical small cell carcinoma and adenocarcinoma has been identified by in situ and blot hybridization analysis using radionucleotide-labeled DNA and RNA probes. We attempted to detect HPV DNA in nine cases each of invasive cervical small cell carcinoma and adenocarcinoma using biotin-labeled probes to HPV types 6/11, 16/31/33/35, and 18 with a peroxidase-conjugated streptavidin detection system. HPV type 18 DNA was detected within four of nine small cell carcinomas and one of nine adenocarcinomas. HPV types 16/31/33/35 were detected in one additional case of cervical adenocarcinoma. All HPV-positive small cell and glandular tumors showed a distinctive, punctate, often juxtanucleolar pattern of nuclear staining which involved the majority of carcinoma cells throughout each neoplasm. This pattern of HPV DNA labeling has not been observed in any of the HPV-positive typical squamous carcinomas or condylomas hybridized at our institution. It is possible that punctate nuclear HPV DNA staining is a marker of viral integration into the host cell genome. We conclude that in situ DNA hybridization with biotinylated probes, although less sensitive than detection of virally transcribed RNA, still allows detection of relatively low copy numbers of HPV DNA in cervical small cell carcinomas and adenocarcinomas. Furthermore, the spatial precision of biotinylated probes may provide morphological information not obtainable using radionucleotide-labeled probes.     

A genotype distribution of human papillomaviruses detected by polymerase chain reaction and direct sequencing analysis in a large sample of common warts in Japan

There have been no large-scale epidemiological studies of human papillomavirus (HPV) genotype distribution of common warts in Japan. A total of 213 patients with common warts (104 males and 109 females) in Japan were studied to detect HPV genotype distribution by polymerase chain reaction (PCR) and direct sequencing analysis. The results were as follows: 94 HPV-1a (44.1%), 35 HPV-4 (16.4%), 30 HPV-65 (14.1%), 13 HPV-27 (6.1%), 13 HPV-2a (6.1%), 9 HPV-57b (4.22%), 3 HPV-16 (1.41%), 2 HPV-6a (0.94%), 2 HPV-63 (0.94%), and 1 case for each of HPV-3, -5, -5b, -7, -10, -21, -29, -47, -56, -57, -62, and -92 (0.47%, respectively). Four cases (1.88%) were found in which two different HPV types were detected within the lesions: one case of HPV-1a with HPV-16, one case of HPV-1a with HPV-65, one case of HPV-6a with HPV-8, and one case of HPV-65 with HPV-16. There were seven cases of mucosal types (3.3%), that is, two HPV-6a, three HPV-16, one HPV-56, and one HPV-62, and three cases of epidermodysplasia verruciformis (EV)-related types (1.41%), that is, one HPV-5, one HPV-5b (both of which belonged to a high-risk group), and one HPV-47 (which belonged to a low-risk group). To date, this is the largest sequencing-based study of HPV for common warts in Japan. It is said that common warts are induced predominantly by HPV-2, -27, and -57 in European population. However, the present results showed that in Japan they were induced mostly by HPV-1, -4, and -65. This suggests that regional differences in HPV genotype distribution may exist between European and Japanese populations.