In situ hybridization analysis of human papillomavirus DNA in oral mucosal lesions

A polymerase chain reaction (PCR) investigation of oral verrucae which contain HPV types 2 and 57 by in situ hybridization

The polymerase chain reaction (PCR) and direct DNA sequencing have been used to identify strain variants of HPV types 2a/57 in formalin-fixed sections of human oral verrucae, where the virus had previously been detected by both immunofluorescence and in situ hybridization. By employing type-specific and type-common PCR primers we show that these lesions contain a mixture of viral DNAs which vary by up to 27% in DNA sequence, in a region where the variation between HPV types 2a and 57 is only 4%. The extra discriminatory power of fluorescent sequencing indicates that the lesions may also contain wild-type HPV2a/57 DNA which could provide a helper function for defective viral DNA molecules or indicate a mosaic origin for the lesions.

Detection of human papilloma virus DNA sequences in oral squamous cell papillomas by the polymerase chain reaction

Nineteen clinically diagnosed, and histologically confirmed oral squamous cell papillomas were analyzed for the presence of human papilloma virus DNA sequence by the highly sensitive polymerase chain reaction technique, followed by dot blot hybridization of the polymerase chain reaction product with digoxigenin-labeled, type-specific oligonucleotide probes for human papilloma virus DNA types 6, 11, 16, and 18. Human papilloma virus DNA types 6 and 11 were identified in 68% of these oral lesions, which raises the possibility of an etiologic role for human papilloma virus in the pathogenesis of oral squamous cell papillomas.

Prognostic evaluation of HPV-associated precancerous and microinvasive carcinoma of the oral cavity: combined use of nucleolar organiser regions (AgNOR) and proliferating cell nuclear antigen (PCNA)

Nucleolar Organiser Regions (NORs) and Proliferating Cell Nuclear Antigen (PCNA) were investigated on routine paraffin embedded histologic sections of 30 oral biopsy specimens (six cases of leukoplakia with low-degree of dysplasia, nine cases of leukoplakia with moderate-degree of dysplasia, nine cases of leukoplakia with severe-degree of dysplasia, six cases of squamous microinvasive carcinomas), tested for HPV-DNA by in situ hybridisation (ISH). The absolute number of NORs per nucleus and the percentage of nuclear positivity for PCNA were found to be different in each group of pathology, with further diversity due to the presence or absence of HPV-DNA. In the major part of HPV-positive lesions, the AgNOR number and percentage of cells positive for PCNA were found to be generally lower than in corresponding negative forms. Conversely, a few cases of HPV+ lesions showed significantly higher values both of AgNOR and PCNA, if compared to the other cases of HPV+ and HPV- lesions. These data suggested that high values of AgNOR and PCNA, in moderate and high grade oral dysplasia, could represent an "alarm signal" of a worse prognosis, and then a possible indication for a strict clinical management and/or a stronger treatment of some HPV-associated preneoplastic lesions.

Association between proliferative verrucous leukoplakia and infection with human papillomavirus type 16

Proliferative verrucous leukoplakia (PVL) is a recently described clinical entity characterized by multifocal oral lesions that frequently progress to oral cancer despite abstinence from tobacco use by most patients. To determine if this condition is associated with human papillomavirus (HPV), a polymerase chain reaction (PCR) for HPV DNA was performed on 9 lesions from 7 patients with PVL, histologically diagnosed with focal keratosis (1), papilloma (1), epithelial dysplasia (5) and squamous cell cancer (2). Eight (89%) were HPV positive, 7 for HPV 16. For comparison, we studied 55 non-PVL-associated oral specimens, including 24 oral squamous cell cancers. Of the cancers, 8 (33%) were HPV positive, 4 for HPV 16. These data suggest that HPV 16 infection may play an important role in the pathogenesis of PVL-associated oral dysplasia and possibly cancer, but is found in only a small proportion of the more common, non-PVL associated-oral lesions.

Oral leukoplakia

Leukoplakia has evolved as a clinico-pathologic concept over many years, with the current clinical designation being accepted worldwide. Reflective of the biology of leukoplakia is the concept of cellular atypia and epithelial dysplasia. Adding to a better understanding of leukoplakia in general has been the definition of relevant clinical subsets which, in some cases, includes etiology (snuff), while in other cases a verrucous clinical appearance will suggest a more aggressive anticipated behavior pattern. Tobacco usage, in many of its forms, remains the prime etiologic factor; however, other considerations also apply. More recently, the potential etiologic role of Candida albicans has been stressed, as well as its possible role in carcinogenesis. So-called oral hairy leukoplakia has been defined in relation to a possible Epstein-Barr viral infection, usually in the immunosuppressed patient. Other viruses, human papilloma virus in particular, have been implicated in leukoplakia, while genetic alterations involving tumor suppressor elements (p53) have also been investigated. Finally, the management of this common condition remains a variable and includes local, topical, and systemic therapies such as anti-oxidants, carotenoids, and retinoids.

Human papillomavirus (HPV) types 2 and 57 in oral verrucae demonstrated by in situ hybridization

Twenty-one cases of verrucae vulgaris (oral warts) were investigated for human papillomavirus (HPV)-group specific antigen by immunocytochemistry and for HPV types 1, 2, 4, 6, 11, 16, 18 and 57 by DNA in situ hybridization with biotinylated probes. Twelve (57%) cases demonstrated the presence of HPV-group specific antigen. Fifteen (71%) cases showed the presence of HPV DNA, 13 of which (87%) demonstrated both HPV types 2 and 57 in the same cells and 2 of which (13%) demonstrated only HPV 2. Six cases were negative for HPV 2 and 57 and all 21 cases (100%) were negative for HPV types 1, 4, 6, 11, 16 and 18. Results indicate the association of a new and as yet unidentified HPV type, closely related to HPV 2 and 57, with oral warts. The identification of both cutaneous type HPV 2 and another type closely related to HPV 2 and 57 in oral verrucae on keratinized and non-keratinized mucosal surfaces indicates the possibility of a latent infection; three patients had a history of warts on their hands, suggesting autoinoculation. This study indicated that future investigations of oral warts, based on a correlation of clinical and histological features with HPV types by DNA in situ hybridization, are called for.

Detection of HPV DNA in oral carcinoma using polymerase chain reaction together with in situ hybridization

This study determined the prevalence of human papillomavirus 16/18 DNA in deparaffinized oral carcinoma specimens on slides with the use of the different sensitivities of in situ hybridization and a technique that combines polymerase chain reaction and in situ hybridization. Human papillomavirus DNA was not detected in the 30 biopsy specimens analyzed by in situ hybridization alone using biotinylated DNA probes specific for human papillomavirus 16/18. Twenty of 30 specimens (66.7%) were found to have human papillomavirus DNA (p < 0.001) with the use of the polymerase chain reaction-in situ hybridization technique. Human papillomavirus 16 was detected in 18 of 26 specimens (69.2%), and 7 of 25 carcinomas (28%) were found to contain human papillomavirus 18. Dual infections were present in 5 of 21 (23.8%) specimens. Human papillomavirus DNA was more prevalent in men (75%) than women (57.1%). However, there was no difference in the mean age of patients with oral carcinoma (men, 67.8 years; women, 67.5 years) who had human papillomavirus and those who did not (67.2 years). Carcinomas associated with dual infections occurred at a lower mean age (59.4 years) than those associated with a single human papillomavirus type (p < 0.005). We conclude that the polymerase chain reaction-in situ hybridization technique enhances our ability to demonstrate human papillomavirus types highly associated with oral squamous cell carcinoma.

Human papillomavirus DNA in oral squamous cell carcinomas and normal mucosa

Human papillomavirus (HPV) infections in oral carcinomas and normal oral mucosa were studied by consensus primer screening and typing for HPV types 6/11, 16 and 18 DNA. After polymerase chain reaction (PCR) the DNA species of interest were identified by Southern blot hybridization with digoxigenin-labeled oligonucleotide probes. Frozen tissue and scrapings were equally suitable for HPV testing and yielded high HPV detection rates in carcinomas. By comparison, HPV analysis of paraffin-embedded material was much less efficient. HPV were demonstrated in 61.5% (16/26) of oral squamous cell carcinomas, high risk HPV 16 and 18 being the preferential types. The frequency of HPV detection in non-neoplastic mucosa of tumor patients decreased clearly with increasing distance from the tumor (range 26.9-3.8%) suggesting focal HPV infections. In contrast, normal buccal mucosa of a group of healthy volunteers contained HPV DNA only in 1% (1/97).

Human herpes simplex-1 and papillomavirus type 16 homologous DNA sequences in normal, potentially malignant and malignant oral mucosa

We have tested a range of normal, potentially malignant and malignant oral mucosal biopsies tissues by Southern blot hybridisation analysis for the simultaneous presence of HSV-1 and HPV type 16 DNA sequences, both of which have been implicated as risk factors in oral carcinogenesis. The results show that: (1) 2/4 patients with lichen planus, 2/4 patients with non-specific keratosis, 1/8 patients with oral carcinoma and 3/5 biopsy specimens of normal oral mucosa contained DNA sequences homologous to the HSV-1, Bam HI-G fragment. (2) HPV-16 homologous DNA sequences were detected in 3/4 patients with lichen planus, 4/4 non-specific keratosis, 4/8 oral carcinomas and in 3/5 biopsy specimens of normal oral mucosa. (3) Overall, only 5 patient biopsy specimens were positive for both HSV-1 and HPV-16 homologous DNA sequences; 2 lichen planus, 2 non-specific keratosis and 1 normal. The data cannot exclude a "hit and run" oncogenic mechanism for HSV but suggest that if HSV-1 and HPV-16 play a synergistic role in the development of oral cancer this may be an early event. Indeed, the data suggest HSV might be more frequently found in potentially malignant lesions than in carcinoma.

Analysis of human papillomavirus DNA in oral squamous cell carcinomas

Evidence from several laboratories suggests that HPV plays a role in the etiology of squamous cell carcinomas of the oral cavity. A multifactorial risk factor profile for the development of oral cancer may include HPV in addition to well-established risk factors such as tobacco and alcohol use. The prevalence of oral carcinomas reported to be associated with HPV has varied widely due to differences in the sensitivity of the assay used for HPV detection. The aims of this study were: (1) to ascertain the prevalence of HPV DNA in oral squamous cell carcinomas using the most sensitive technique available, the polymerase chain reaction; (2) to determine the type of HPV in the tumors; and 3) to correlate the virologic data with other risk factor data obtained from patients' records. Fourteen (78%) of 18 primary tumors, 6 (67%) of 9 normal epithelial tissues from the patients and 5 (100%) of 5 neck metastases were HPV DNA-positive. Of the 14 HPV DNA-positive primary tumors, specific typing revealed HPV 16 in 2, HPV 18 in 2, HPV 16 and 18 in 5, HPV 6/11, 16 and 18 in 4, and HPV 6/11 in 1. HPV types in the normal or metastatic tissue were usually the same as those in the respective primary tumor. There was no significant association between HPV presence and any of 12 factors or patient characteristics studied.

Assessment of p53 protein expression in normal, benign, and malignant oral mucosa

Recent studies have shown the accumulation of high levels of p53 protein to be associated with malignant disease, within a range of tissues. This paper assesses p53 expression in oral mucosal disease. Biopsies were obtained from a range of oral disorders which included normal, benign, premalignant, and malignant oral tissue. In addition, oral smears were obtained from a limited number of patients with biopsy-proven oral cancer. Expression of the p53 protein was assessed using the polyclonal antibody CM1, together with a standard immunoperoxidase technique. A total of 37 oral cancers were assessed, of which 20 were found to express the p53 protein (54 per cent of cases). The p53 protein was not identified in normal, benign, or premalignant oral mucosa (54 cases). The identification of p53 within biopsies of oral mucosal lesions would appear to correlate with oral malignancy.