Nested PCR for detection of HSV-1 in oral mucosa.

BACKGROUND: It has been estimated that 15%-20% of human tumours are driven by infection and inflammation, and viral infections play an important role in malignant transformation. The evidence that herpes simplex virus type 1 (HSV-1) could be involved in the aetiology of oral cancer varies from weak to persuasive. This study aimed to investigate by nested PCR (NPCR) the prevalence of HSV-1 in samples from normal oral mucosa, oral leukoplakia, and oral squamous cell carcinoma (OSCC). MATERIAL AND METHODS: We investigated the prevalence of HSV-1 in biopsies obtained from 26 fresh, normal oral mucosa from healthy volunteers as well as 53 oral leukoplakia and 27 OSCC paraffin-embedded samples. DNA was extracted from the specimens and investigated for the presence of HSV-1 by nested polymerase chain reaction (NPCR) and DNA sequencing. RESULTS: HSV-1 was detected in 14 (54%) of the healthy samples, in 19 (36%) of the oral leukoplakia samples, and in 14 (52%) of the OSCC samples. The differences were not statistically significant. CONCLUSIONS: We observed a high incidence of HSV-1 in healthy oral mucosa, oral leukoplakia, and OSCC tissues. Thus, no connection between OSCC development and presence of HSV-1 was detected.

Presence of human papilloma virus, herpes simplex virus and Epstein-Barr virus DNA in oral biopsies from Sudanese patients with regard to toombak use.

Using PCR/DNA sequencing, we investigated the prevalence of human papillomavirus (HPV), herpes simplex virus (HSV) and Epstein-Barr virus (EBV) DNA in brush biopsies obtained from 150 users of Sudanese snuff (toombak) and 25 non-users of toombak in formalin-fixed paraffin-embedded tissue samples obtained from 31 patients with oral dysplasias (25 toombak users and 6 non-users), and from 217 patients with oral cancers (145 toombak users and 72 non-users). In the brush tissue samples from toombak users, HPV was detected in 60 (40%), HSV in 44 (29%) and EBV in 97 (65%) of the samples. The corresponding figures for the 25 samples from non-users were 17 (68%) positive for HPV, 6 (24%) positive for HSV and 21 (84%) for EBV. The formalin-fixed samples with oral dysplasias were all negative for HPV. In the 145 oral cancer samples from toombak users, HPV was detected in 39 (27%), HSV in 15 (10%) and EBV in 53 (37%) of the samples. The corresponding figures for the samples from non-users were 15 (21%) positive for HPV, 5 (7%) for HSV and 16 (22%) for EBV. These findings illustrate that prevalence of HSV, HPV and EBV infections are common and may influence oral health and cancer development. It is not obvious that cancer risk is increased in infected toombak users. These observations warrant further studies involving toombak-associated oral lesions, to uncover the possible mechanisms of these viral infections in the development of oral cancer, and the influence of toombak on these viruses.

Prevalence of human papillomavirus in oral lichen planus in an Iranian cohort.

CONTEXT: Oral lichen planus (OLP) is a chronic inflammatory mucocutaneous disease with female predominance with the potential for malignant transformation. Human papillomavirus (HPV) is associated with both malignant and benign disease in the head and neck region. AIMS: The present study assesses the prevalence of high-risk HPV-16 and HPV-18 in tissue and saliva samples from an Iranian population diagnosed with OLP. SUBJECTS AND METHODS: Deoxyribonucleic acid was extracted and investigated using polymerase chain reaction from tissue and saliva samples of the same individuals from 40 OLP cases and saliva samples of 40 healthy controls. STATISTICAL ANALYSIS: The prevalence of data was compared using the Chi-square test and inter-group differences were analyzed using Fisher's exact test. RESULTS: OLP specimens were HPV-positive in 11 of 40 (27.5%) cases compared with three of 40 (7.5%) saliva specimens, representing a statistically significant difference (P = 0.0367). HPV-16 and HPV-18 were positive in eight of 40 (20%) OLP tissues and three of 40 (7.5%) saliva samples. Five of the 40 healthy saliva samples were positive for HPV-16. In the OLP patients with dysplasia, four of seven tissue samples were HPV-positive; threeof these four were HPV-16- positive in comparision with seven of 33 HPV-positive samples from OLP patients without dysplasia. CONCLUSIONS: Biopsies were more accurate than saliva analysis for evaluating HPV prevalence in OLP patients. HPV prevalence was higher in dysplastic than nondysplastic OLP lesions in this Iranian cohort.

Comparison between single PCR and nested PCR in detection of human papilloma viruses in paraffin-embedded OSCC and fresh oral mucosa.

BACKGROUND: Infection with human papilloma virus (HPV) has been implicated as one of the risk factors for the development of oropharyngeal cancer. Many different HPV tests exist, and information regarding their specific technical, analytical, and clinical properties is increasing. AIM: This study aimed to compare the level of detection of HPV using two reliable polymerase chain reaction (PCR) methods, nested PCR (NPCR) and single PCR (SPCR), in archival paraffin-embedded oral squamous cell carcinoma (OSCC) samples and fresh oral mucosa specimens. MATERIALS AND METHODS: The presence of HPV genome in two groups of tissue samples was analyzed: (i) 57 paraffin-embedded OSCC samples from Sudan and (ii) eight healthy fresh oral mucosal samples from Swedish volunteers. The specimens were tested by SPCR with primer pair MY9/MY11 and NPCR using GP5+/GP6+ primer sets. RESULTS: Eighteen (32%) out of the 57 paraffin-embedded OSCC samples, and five (62%) out of the eight fresh clinically healthy samples were found to be HPV-positive with NPCR. With SPCR, four (7%) out of the paraffin-embedded OSCC samples were HPV-positive. A statistically significant difference between HPV-positive and -negative samples was found when comparing NPCR and SPCR in OSCC and fresh oral mucosa (p<0.0001). The comparative test between SPCR and NPCR showed 100% sensitivity and 69% specificity for OSCC. CONCLUSION: The use of the GP5+/GP6+ nested PCR increased the positivity rate, efficiency rate and sensitivity of HPV detection in oral samples significantly and should be considered as the method of choice.

Prevalence of Epstein-Barr virus in oral squamous cell carcinoma, oral lichen planus, and normal oral mucosa.

OBJECTIVE: The Epstein-Barr virus (EBV) is associated with both malignant and benign diseases in the head and neck region. In several studies it has also been associated with oral squamous cell carcinoma (OSCC). Oral lichen planus (OLP) is a disease with unknown origin, and viral antigens have been proposed as etiologic agents. Smoking and alcohol habits are known risk factors for oral cancer development. In this study, the prevalence of EBV in OSCC and OLP was investigated, along with the effect of smoking, alcohol use, and age on EBV prevalence. STUDY DESIGN: We examined 29 patients with OSCC, 23 with OLP, and 67 with clinically healthy oral mucosa. For EBV DNA analysis, a nested polymerase chain reaction method was used. RESULTS: The overall EBV prevalence in patients with oral disease was 32.1%. Of the OSCC patients, 37.9% were EBV positive; and of the OLP patients, 26.1% were EBV positive. Both percentages were statistically significant compared with that of control patients (7.3%). The difference in EBV prevalence between the smoking control group and the nonsmoking control group was insignificant. Increased age did not enhance EBV prevalence. CONCLUSIONS: This investigation shows that EBV is present in oral diseases such as OSCC and OLP. Smoking, alcohol use, or age does not seem to be a risk factor for EBV infection. The etiologic role of EBV in OSCC and OLP needs to be examined in a prospective follow-up study.

Viruses and oral cancer. Is there a link?

Oral squamous cell carcinoma (OSCC) is the most common malignant tumour of the oral cavity. The aetiology of epithelial cancer of the head and neck is considered to be a multifactorial, sequential process. DNA viruses are found in many different cancers and are also capable of transforming cells to a malignant phenotype. Human Papilloma Virus (HPV) has been proposed as risk factors in OSCC development and HPV type 16 is the most important subtype. Other oncogenic virus species i.e., Epstein-Barr Virus and Herpes Simplex Virus Type 1 have been proposed to be involved in oral carcinogenesis. However, no convincing evidence exist that they are an established risk factor in OSCC. Therefore more studies are needed in order to clarify the different aspects of virus involvement. Here, we review the existing literature on viral involvement in oral cancer.

p53 Codon 72 polymorphism in oral exfoliated cells in a Sudanese population.

Earlier studies have investigated the tumor suppressor gene p53 as a co-factor in the development of oral squamous cell carcinoma (OSCC). Our previous studies have indicated that chronic use of Sudanese snuff (toombak) and the presence of human papilloma virus (HPV) may be involved in the high prevalence of OSCC in Sudan. This study investigated the prevalence of p53 codon 72 polymorphism in brush biopsies obtained from a Sudanese population. A total of 174 individuals were included in the study; chronic toombak users (n=152) and non-users (n=22). DNA was extracted from all the samples and genotyped for the codon 72 polymorphism by polymerase chain reaction/restriction fragment length polymorphism. The Arg/Pro genotype was found in 53% of the 174 study participants, compared to 21% found with Arg/Arg and 26% found with Pro/Pro. Stratifying by toombak use, 28 (18%), 45 (29%) and 79 (52%) of the 152 samples from toombak users had Arg/Arg, Pro/Pro and Arg/Pro respectively, compared to 9 (41%), 0 (0%) and 13 (59%) found in the 22 samples from non users. The differences between the samples from toombak users and non users in Arg/Arg and Pro/Pro codon 72 polymorphism and HPV infection were statistically significant (p<0.05). Our study indicated that a high prevalence of the genotype Arg/Pro at the p53 codon 72 may contribute to susceptibility to OSCC, especially in combination with the use of carcinogenic tobacco-specific nitrosamine (TSNA)-rich toombak. Our observations warrant an in-depth study for understanding the role of p53 polymorphism in human oral cancers.

Viral and molecular aspects of oral cancer.

Squamous cell carcinoma (SCC) is the most common epithelial malignancy in the oral cavity. SCCs and their variants constitute over 90% of oral malignancies, and the disease is associated with poor prognosis. OSCC is a complex malignancy where environmental factors, virus infections, and genetic alterations most likely interact, and thus give rise to the malignant condition. Herein, we review the available literature regarding high-risk factors such as alcohol and tobacco usage; discuss the roles of human papillomaviruses (HPV), the Epstein-Barr virus, and the human herpes simplex virus (HSV); and evaluate several candidate genes associated with the condition: p53, p16(INK4) and p21(WAF1/CIPI), survivin, B-cell lymphoma-2 (BCL-2), keratins, Fibroblast growth factor 3 (FGF3), FGF4, FGF19, Oral cancer overexpressed gene 1 (ORAOV1), and Cyclin D1 (CCND1).

Human papilloma virus, herpes simplex virus and epstein barr virus in oral squamous cell carcinoma from eight different countries.

Oral squamous cell carcinoma (OSCC) is a major health problem in many parts of the world, and the major causative agents are thought to be the use of alcohol and tobacco. Oncogenic viruses have also been suggested to be involved in OSCC development. This study investigated the prevalence of human papillomaviruses (HPV), herpes simplex virus (HSV) and Epstein-Barr virus (EBV) in 155 OSCC from eight different countries from different ethnic groups, continents and with different socioeconomic backgrounds. 41 A total of OSCCs were diagnosed in the tongue (26%) and 23 in the floor of the mouth (15%); the other 91 OSCCs were diagnosed in other locations (59%). The patients were also investigated regarding the use of alcohol and smoking and smokeless tobacco habits. Tissue samples were obtained from formalin-fixed, paraffin-embedded samples of the OSCC. DNA was extracted and the viral genome was examined by single, nested and semi-nested PCR assays. Sequencing of double-stranded DNA from the PCR product was carried out. Following sequencing of the HPV-, HSV- and EBV-positive PCR products, 100% homology between the sampels was found. Of all the 155 OSCCs examined, 85 (55%) were positive for EBV, 54 (35%) for HPV and 24 (15%) for HSV. The highest prevalence of HPV was seen in Sudan (65%), while HSV (55%) and EBV (80%) were most prevalent in the UK. In 34% (52/155) of all the samples examined, co-infection by two (46/155=30%) or three (6/155=4%) virus specimens was detected. The most frequent double infection was HPV with EBV in 21% (32/155) of all OSCCs. There was a statistically significant higher proportion of samples with HSV (p=0.026) and EBV (p=0.015) in industrialized countries (Sweden, Norway, UK and USA) as compared to developing countries (Sudan, India, Sri Lanka and Yemen). Furthermore, there was a statistically significant higher co-infection of HSV and EBV in samples from industrialized countries (p=0.00031). No firm conclusions could be drawn regarding the relationship between alcohol, tobacco and virus infections. The significance of our findings must be put in relation to other risk factors and these observations warrant further studies to determine the possible role of viral infections and co-infections with HPV, EBV and HSV as risk markers for the development of OSCC.

Differential expression of apoptosis, cell cycle regulation and intermediate filament genes in oral squamous cell carcinomas associated with toombak use in Sudan.

Previously we used microarray genomic hybridization technology to explore genome-wide profiles of chromosomal aberrations in samples of oral squamous cell carcinomas (OSCCs) and paired normal controls. Based on these findings, 9 genes related to apoptosis, cell cycle regulation and intermediate filament proteins were selected and their differential expression status was examined by real-time quantitative RT-PCR in 26 samples of Sudanese OSCCs and their matched normal controls. The findings were correlated with the habit of toombak use. The mRNA levels of Bcl2, keratin 1, keratin 13 and p53 were significantly lower and the level of survivin was significantly higher in the OSCC samples of the toombak users compared to their paired control samples. A significant down-regulation in keratin 1 and keratin 13 expression levels was found in the OSCC samples of the nontoombak users compared to their normal control samples. The differential expression of genes related to apoptosis, cell cycle regulation and types I and II keratin could be useful diagnostic markers and provide valuable information for the understanding of oral malignancy in relation to toombak use.

Prevalence of viral (HPV, EBV, HSV) infections in oral submucous fibrosis and oral cancer from India.

CONCLUSION: There is a high prevalence of human papilloma viruses (HPV) in oral submucous fibrosis (OSMF) and the etiologic implication of this finding warrants further studies. OBJECTIVE: The prevalence of oral squamous cell carcinoma (OSCC) and OSMF is high in India, and the diseases are partly attributed to high consumption of betel quid containing areca nut and tobacco. This study investigated the prevalence of HPV, herpes simplex virus (HSV), and Epstein­Barr virus (EBV) DNA in two groups of patients using betel quid with tobacco, those with OSMF (n = 12) and those with OSCC (n = 62). METHODS: DNA was extracted from all the samples and viral genome was examined by PCR/DNA sequencing. HPV-positive samples were analyzed separately for the high-risk types HPV 16 and 18. RESULTS: HPV DNA, HSV DNA, and EBV DNA were detected in 11 (91%), 1 (8%), and 3 (25%) of the 12 samples from patients with OSMF compared with 15 (24%), 3 (5%), and 18 (29%), respectively, from 62 patients with OSCC. HPV 16 and 18 DNA was detected in 8/12 (67%) in the OSMF group and 10/62 (16%) in the OSCC group. The difference between presence of HPV DNA in OSMF and OSCC groups was statistically significant, while the difference between HSV and EBV DNA content in OSMF and OSCC groups was insignificant.