Highly sensitive detection of HPV-DNA in paraffin sections of human oral carcinomas

Human papillomavirus-16 infection and p16 expression in oral squamous cell carcinoma

Human papillomavirus (HPV) is a possible carcinogenetic factor in oral squamous cell carcinoma (OSCC). Previous studies have reported the prevalence of HPV in patients with OSCC. However, the association between HPV and OSCC remains controversial. The present study aimed to clarify the association between HPV infection, p16 protein expression and the clinicopathological characteristics of OSCC. The expression level of HPV-16E6 mRNA and p16 protein, a known surrogate marker of HPV infection, was investigated in 100 OSCC cases using TaqMan reverse transcription-quantitative PCR and immunohistochemistry staining, respectively. HPV-16E6 mRNA expression level was only detected in one case (1%), and positive expression of p16 was found in 10 cases (10%), including an HPV-positive case. Subsequently, the association between p16 expression level and clinicopathological characteristic factors were analyzed; however, no significant association was found. These results suggested that HPV-16 infection was less likely to cause OSCC in Japan and p16 expression was not a suitable marker for HPV infection in OSCC.

Evaluation of HPV and EBV in OSCC and the expression of p53, p16, E-cadherin, COX-2, MYC, and MLH1

OBJECTIVE

This study aimed to evaluate the presence of human papillomavirus (HPV) and Epstein-Barr virus (EBV) and the expression of p53, p16, E-cadherin, COX-2, MLH1, and MYC in oral squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

One hundred OSCC specimens were submitted to in situ hybridization for HPV and EBV, and immunohistochemistry for detection of the human proteins.

RESULTS

Thirty-one cases showed HPV in tumor tissue. EBV was not detected in any case investigated. The HPV(+) group demonstrated an increase of staining scores for nuclear p16 (p = .047), cytoplasmic MYC (p = .002), while a decrease for nuclear MLH1 (p = .048), suggesting that HPV may upregulate the expression of the first two proteins and down-regulate the latter.

CONCLUSION

Our findings reinforce the hypothesis of the HPV-related oral carcinogenesis involving the expression of p16 and MYC, and MLH1 suppression. Exclusively cytoplasmic stainings for p16, MLH1, and MYC were also associated with more advanced tumors. Finally, in view of the lack of studies correlating the HPV or EBV infection to the expression of oncoproteins, more researches assessing a broader panel of markers and employing different approaches are still necessary in order to understand the role of these viruses as well as the molecular mechanisms involved in the development and progression of oral carcinomas.

Molecular and Immunohistochemical Cognizance of HPV16 in Oral Leukoplakia, Oral Squamous Cell Carcinoma and Oropharyngeal Squamous Cell Carcinoma

Prior studies have established the carcinogenic role of HPV16 and also demonstrated its unique biological behavior in cervical and oropharyngeal squamous cell carcinoma (OPSCC) but its role in oral leukoplakia (OL) and oral squamous cell carcinoma (OSCC) is not well explored. Therefore, in the present study, we assessed HPV16 prevalence using PCR and Anti-HPV16 antibodies for the first time and correlated its biological behavior using p16^INK4a and Ki67 proliferation index (PI) in OL, OSCC, and OPSCC. This study included 63 subjects comprising of 25 OL, 26 OSCC, and 12 OPSCC cases. Exfoliated cells were collected and processed for PCR followed by immunohistochemistry with primary antibodies p16^INK4a, Anti-HPV16, and Ki67. The expressions were evaluated and statistical analysis included Chi-square and Spearman's test. Cumulatively 37% (OL-7%, OSCC-14% & OPSCC-16%) of cases showed positive PCR expression. PCR positivity was observed to be significantly higher (p 0.00) in OPSCC (9/12) than OSCC (9/26) and OL (5/25) cases. Overall immunohistochemical expression of p16^INK4a, Anti-HPV16, and Ki67 were significantly (p 0.02) higher in HPV16 (PCR) positive cases. HPV16 + OSCC cases showed higher grades of p16^INK4a and Ki67 expression. We have demonstrated a prevalence of HPV16 in OL, OSCC, and OPSCC through PCR, which may be concluded as a gold standard for the detection of HPV16 DNA.

Importance of human papillomavirus infection in squamous cell carcinomas of the tongue in Guangdong Province, China

Objective

Methods

Results

Conclusion

Correlation of p53 Expression with Histopathological and Immunohistochemical Features of Human Papillomavirus in Oral Leukoplakia

Background

Oral cancer is strongly associated with the habit of tobacco chewing, alcohol, and betel quid consumption in India. However, sometimes, majority of the population develop oral cancer without exposure to these risk factors and are sometimes cautious about their fitness, suggesting that additional causes such as genetic predisposition, diet, and viral agents may be associated which need to explored.

Aims and Objectives

The aim of this study was to establish a possible correlation between clinical types of leukoplakia with their histopathological features of high-risk human papillomavirus (HPV) infection and the presence or absence of HPV and expression of p53through immunohistochemistry (IHC).

Materials and Methods

Sample comprised of 40 cases of leukoplakia and 10 cases as control group. Three sections were prepared from each biopsy and subjected to IHC and hematoxylin and eosin (H and E) stain, respectively. IHC-stained slides were used to evaluate the expression of p53 and HPV and then correlated with the features of HPV infection using H and E staining. Chi-square test with a statistical analysis software package (SPSS software Version 20.0) was used.

Observation and Results

The P value for p53 against HPV (IHC) was 0.012, which indicates a significant difference between positivity proportion of P53 and HPV (IHC), whereas the P value for koilocyte and HPV (IHC) is 0.311, which is nonsignificant and indicates no significance of difference between proportion of positivity between koilocyte and HPV (IHC).

Conclusion

The expression of p53 was proportionally significant to the expression of positivity of HPV, but there was no significant association between koilocyte and p53 expression.

Prevalence of HPV in Oral Squamous Cell Carcinoma in South West India

There are inconsistent reports regarding the role of HPV in the origin and progression of oral squamous cell carcinoma (OSCC). The observed heterogeneity was mainly attributed to the social and cultural habits of the enrolled cases, discrepancies in the nature of samples procured and varying sensitivity of the assays employed for detection of HPV. The objective of this study was to assess the prevalence of HPV in OSCC in South West India. This was a cross sectional study conducted over a period extending from October 2015 to June 2017. This study involved Department of ENT-Head and Neck Surgery and Department of Virology, Manipal Academy of Higher Education. Fifty histologically confirmed oral squamous cell carcinoma patients undergoing wide local excision of the tumour were enrolled for the study. Intraoperatively 4-5 mm of tissue samples were transported in sterile normal saline at 4-80 °C. The primary screening of tissue samples was performed by nested PCR using PGMY09/11 consensus primers and GP5+/6+ consensus primers and TaqMan based real time multiplex PCR for HPV-16, HPV-18, HPV-31 and HPV-45. All samples tested negative for HPV DNA by conventional nested PCR and TaqMan based real-time Multiplex PCR ruling out four common HPV subtypes such as HPV-16, 18, 31, 45. We did not find presence of HPV DNA in the tissues of patients with OSCC from southwest India. However, studies with more geographic representation from other parts of India are required before generalising our findings.

Frequency of Human Papillomavirus (HPV) 16 and 18 Detection in Paraffin- Embedded Laryngeal Carcinoma Tissue

Background and Objective: Human papilloma virus (HPV) 16 and HPV18 have been detected in head and neck squamous cell carcinomas (HNSCC) and there is evidence that detection of HPVs would have better prognostic value than patients with HNSCC negative for HPVs. Thus, this study was conducted to evaluate frequency of HPV 16 and HPV 18 genotypes in patients with laryngeal carcinoma. Materials and methods: Fifty formalin-fixed, paraffin-embedded (FFPE) tissue blocks of laryngeal cancers were collected. Sections were prepared at 5 μm and DNA was extracted from each sample and subjected to the polymerase chain reaction (PCR) to detect HPV-16/18 DNA s. Results: All samples were squamous cell carcinomas (SCCs). Overall 14/50 (28%) were positive for HPVs, 8 (18%) with HPV-16 and 6 (12%) with HPV-18. Additionally, 2 (4%) mixed infections of HPV 16 and 18 genotypes were observed among these cases. Conclusions: Overall, 28% of HNSCC samples proved positive for HPV16 and HPV18 genotypes, two high-risk HPV types. It is important to further assess whether such viral infection, could be a risk factor in HNSCC progression.

Human Papilloma Virus in Oral Cavity Cancer and Relation to Change in Quality of Life Following Treatment-a Pilot Study from Northern India

Human papilloma virus (HPV)-associated head and neck cancer (HNC) has generated significant amount of research interest in recent times with focus shifted to oral cavity squamous cell cancer (OCSCC) after oropharyngeal cancer. Due to high incidence of OCSCC and anecdotal reports on association of HPV infection from northern region of India, this study was conceived to investigate HPV infection and establish its association with lifestyle habits such as tobacco, alcohol consumption, oro-genital sex, number of sexual contacts, and change in quality of life posttreatment. A total of 43 primary OCSCC biopsy specimens were collected. These samples were analyzed for HPV DNA genotyping which was done by using 13 high-risk HPV real-time PCR kits. Quality of life was assessed using University of Washington questionnaire for HNC patients, which was administered pretreatment and 3-months posttreatment. HPV presence was confirmed in only three patients (7.0 %). HPV positivity did not find any statistical correlation with age, gender, residence, addiction habit, stage, tumor size, nodal status, tumor grade, and number of sexual contacts. There was no significant (p > 0.05) difference in the average percent change in QOL parameters from pretreatment to posttreatment when correlated with HPV status.

Prevalence of human papillomavirus in oral squamous cell carcinomas in northern Spain

The aim of this study was to analyze the prevalence of high-risk HPV in oral squamous cell carcinoma (OSCC) in a northern Spanish population, as well as to ascertain the prognostic role of p16^INK4a expression. The examination samples were collected from paraffin tissue blocks, from 125 patients surgically treated between 1996 and 2007. All cases were histologically evaluated, and the presence of HPV was assessed by p16 and p53immunohistochemistry followed by DNA detection by in situ hybridization (ISH) and polymerase chain reaction (PCR) amplification using the combination of consensus primers MY11/GP6 + . Fourteen cases (11 %) were p16-immunopositive, and p53 was scored positive in 73 cases (58 %). Five cases (4 %) showed a simultaneous p16-positive and p53-negative immunostaining. ISH was negative in all the cases. Among the p16INK4a-immunopositive cases, PCR amplification failed to reveal HPV DNA in any tumor samples. There were no statistically significant differences in any clinical or pathological characteristics of the patients regarding p16^INK4a expression. T classification, neck-node metastasis, and clinical stage showed outcome relevance. However, no significant differences in cause-specific survival based on p16INK4a were observed. We did not find any high-risk HPV types in our patients, thus, are unlikely that HPV has an important role in the etiology of OSCC. p16INK4a protein was neither an accurate marker of HPV infection nor a prognosis marker in OSCC.

Human Papillomavirus in Oral Leukoplakia, Verrucous Carcinoma, Squamous Cell Carcinoma, and Normal Mucous Membrane

OBJECTIVES

Squamous cell carcinoma (SCC) is the most common oral malignancy, and verrucous carcinoma (VC) is a less invasive type of SCC. Leukoplakia (LP) is the most frequent premalignant lesion in the oral cavity. The human papillomavirus (HPV) has been recognized as one of the etiologic factors of these conditions. The association of anogenital and cervical cancers with HPV particularly its high-risk subtypes (HPV HR) has been demonstrated. The purpose of our study was to investigate the hypothetical association between HPV and the mentioned oral cavity lesions.

METHODS

One hundred and seventy-three samples (114 SCCs, 21 VCs, 20 LPs) and 18 normal mucosa samples (as a control group) were retrieved from the Department of Oral and Maxillofacial Pathology of Mashhad Dental School, Iran. The association of HPV genotypes in LP, VC, and SCC was compared to normal oral mucosa using the polymerase chain reaction.

RESULTS

The results showed the absence of HPV in normal mucosa and LP lesions. In three samples of VC (14.3%), we observed the presence of HPV HR (types 16 and 18). All VCs were present in the mandibular ridge of females aged over 65 years old. No statistically significant correlation between HPV and VC was observed (p=0.230). Additionally, 15 (13.1%) SCCs showed HPV positivity, but this was not significant (p=0.830). The prevalence of SCC was higher on the tongue with the dominant presence of less carcinogenic species of HPV (types 6 and 11). A statistically significant association was not observed between HPV and SCC or VC in the oral cavity.

CONCLUSION

More studies are necessary to better understand the relationship between HPV and malignant/premalignant oral cavity lesions.

Alcohol and Tobacco Increases Risk of High Risk HPV Infection in Head and Neck Cancer Patients: Study from North-East Region of India

BACKGROUND

Human papilloma virus (HPV) associated Head and Neck Cancers (HNCs) have generated significant amount of research interest in recent times. Due to high incidence of HNCs and lack of sufficient data on high-risk HPV (hr-HPV) infection from North -East region of India, this study was conceived to investigate hr-HPV infection, its types and its association with life style habits such as tobacco, alcohol consumption etc.

METHODS

A total of one hundred and six primary HNC tumor biopsy specimens were collected. These samples were analyzed for hr-HPV DNA (13 HPV types) using hybrid capture 2 (HC2) assay and genotyping was done by E6 nested multiplex PCR (NMPCR).

RESULTS

The presence of hr-HPV was confirmed in 31.13% (n = 33) and 24.52% (n = 26) of the HNC patients by nested multiplex PCR (NMPCR) and HC2 assay respectively. Among hr-HPV positive cases, out of thirteen hr- HPV types analyzed, only two prevalent genotypes, HPV-16 (81.81%) followed by HPV-18 (18.18%) were found. Significant association was observed between hr-HPV infection with alcohol consumption (p <0.001) and tobacco chewing (p = 0.02) in HNC cases. Compared to HPV-18 infection the HPV-16 was found to be significantly associated with tobacco chewing (p = 0.02) habit.

CONCLUSIONS

Our study demonstrated that tobacco chewing and alcohol consumption may act as risk factors for hr-HPV infection in HNCs from the North-East region of India. This was the first study from North-East India which also assessed the clinical applicability of HC2 assay in HNC patient specimens. We suggest that alcohol, tobacco and hr- HPV infection act synergistically or complement each other in the process of HNC development and progression in the present study population.

Detection and typing of human papillomaviruses (HPV) in malignant, dysplastic, nondysplastic and normal oral epithelium by nested polymerase chain reaction, immunohistochemistry and transitional electron microscopy in patients of northern Greece

OBJECTIVES

To evaluate the role of HPV in oral carcinogenesis, we examined the prevalence of HPV in malignant, potentially malignant and normal oral epithelium and studied the relation of HPV prevalence with other factors obtained from the patient's records.

MATERIALS AND METHODS

Our material consisted of 291 tissue specimens from 258 individuals. From every individual formalin fixed and paraffin embedded tissues were examined by nested Polymerase Chain Reaction (NPCR) for the detection of HPV DNA and by immunohistochemistry (IHC) for the in situ detection of HPV L1 protein. Positive PCR products were sequenced in order to type HPVs. Also 33 fresh tissues were obtained, fixed and used to detect HPV particles by transitional electron microscopy (TEM).

RESULTS

HPV was detected in 32.9% of the tissue specimens by NPCR, in 4.7% by immunohistochemistry and in 28.1% by TEM. In detail, by nested PCR HPV L1 DNA was detected in 40% of normal tissues, 40% of fibromas, 35.8% of non-dysplastic leukoplakias, 31.6% of dysplastic leukoplakias and 22.2% of oral squamous cell carcinomas. The HPV viral load of 96.5% of the samples was very low (1 viral copy per 10(2)-10(4) cells). HPV16 prevails in all histological groups in 89-100%.

CONCLUSION

We conclude that HPV does not seem, from the specific sample examined, to play a substantial role in oral carcinogenesis. However, it cannot be excluded that HPV could be involved in oral carcinogenesis only in cases with high viral load or at early stages of carcinogenesis possibly through the hit-and-run mechanism.

Evidences suggesting involvement of viruses in oral squamous cell carcinoma

Oral cancer is one of the most common cancers and it constitutes a major health problem particularly in developing countries. Oral squamous cell carcinoma (OSCC) represents the most frequent of all oral neoplasms. Several risk factors have been well characterized to be associated with OSCC with substantial evidences. The etiology of OSCC is complex and involves many factors. The most clearly defined potential factors are smoking and alcohol, which substantially increase the risk of OSCC. However, despite this clear association, a substantial proportion of patients develop OSCC without exposure to them, emphasizing the role of other risk factors such as genetic susceptibility and oncogenic viruses. Some viruses are strongly associated with OSCC while the association of others is less frequent and may depend on cofactors for their carcinogenic effects. Therefore, the exact role of viruses must be evaluated with care in order to improve the diagnosis and treatment of OSCC. Although a viral association within a subset of OSCC has been shown, the molecular and histopathological characteristics of these tumors have yet to be clearly defined.

Oral and pharyngeal cancer in women

Although in the United States the incidence of oral and pharyngeal cancer (OPC) has been significantly higher in men than in women, the identification of human papilloma virus as a risk factor for OPC has focused new scrutiny on who may develop OPC. One surprising element is that non-Hispanic white women have a higher incidence of OPC than of cervical cancer. OPC is thus a woman's disease, and diligence is needed to ensure that the occurrence of OPC in women does not go undetected by their oral health care providers.

Human papillomavirus and head and neck cancer

An increasing subset of patients with head and neck squamous cell carcinoma (HNSCCA) is positive for high-risk human papillomavirus (HR-HPV). Patients tend to be younger, have a minimal or absent tobacco and ethanol abuse history, increased number of lifetime sexual partners (particularly oral-genital sex), and squamous cell carcinomas (SCCAs) arising in the oropharynx. The most common HR-HPV associated with HNSCCA is HPV-16. HR-HPV positivity is associated with decreased expression of the p53 and Rb genes, overexpression of p16, decreased expression of EGFR, and a different genetic expression pattern compared with patients with HR-HPV-negative SCCAs, leading to the conclusion that this is a distinct clinical entity. Patients who have HR-HPV-positive HNSCCAs have an improved prognosis, particularly those with oropharyngeal SCCAs, leading some to speculate that the intensity of treatment might be decreased. At present, whether this can be done safely remains unclear.

Human papillomavirus subtypes in oral lesions compared to healthy oral mucosa

BACKGROUND

Human papillomaviruses (HPV) are involved in the etiology of cervix cancer, but it is still unclear whether they play a role in related oral lesions.

OBJECTIVES

The presence of HPV in oral leukoplakia biopsies (n=50) and oral squamous carcinoma biopsies (n=50) was compared to normal oral mucosa swabs (n=50) for the purpose of indicating a possible etiological role for the virus.

STUDY DESIGN

DNA was extracted from tissue biopsies and from mucosa swabs of control samples. Nested PCR was performed with primers targeting conserved sequences within the capsid gene L1. PCR products were sequenced to identify the HPV genotype.

RESULT

The results reveal a profile of low-risk HPV genotypes in oral leukoplakia similar to that in healthy controls, while HPV was less frequently observed in oral squamous carcinoma.

CONCLUSIONS

HPV does not seem to represent an important causal factor for the development of oral leukoplakia or oral squamous carcinoma.

Low prevalence of high risk genotypes of human papilloma virus in normal oral mucosa, oral leukoplakia and verrucous carcinoma

OBJECTIVE

Squamous Cell Carcinoma (SCC) is the most common malignancy of the oral cavity and Verrucous Carcinoma (VC) is its least invasive form with no metastasis potential. Leukoplakia (clinical term for hyperkeratosis and acanthosis with and without dysplasia) is the most common pre-malignant lesion of the oral cavity. Human Papilloma Virus (HPV) has been recognized as an etiologic factor for mentioned lesions. In this study the relationship between high risk types of this virus (HPV(HR)) with VC and Leukoplakia is investigated.

MATERIALS AND METHOD

Forty-one paraffin-embedded blocks including 21 VC, 20 leukoplakias in addition to 18 normal oral mucosal tissues as the control group were studied by Polymerase Chain Reaction (PCR) to detect HPV 16, 18, 31 and 33.

RESULTS

In three specimens of VCs (14.3%) HPV(HR) was detected. Each of these contained both HPV 16 and 18. All three positive specimens belonged to women older than 65 and were obtained from the vestibule of the mandible. Neither Leukoplakia nor normal mucosa showed HPV presence. No significant relationship between HPV and VC was found compared with the control group (p = 0.23).

CONCLUSION

This study did not show relationship between HPV and leukoplakia. Although no statistically significant relationship was found between HPV and VC, but considering sample size limitation for such uncommon cases, its presence in three cases of 14 makes more investigations to overcome the controversies necessary.

High-risk human papillomavirus (HPV) screening and detection in healthy patient saliva samples: a pilot study

Background

The human papillomaviruses (HPV) are a large family of non-enveloped DNA viruses, mainly associated with cervical cancers. Recent epidemiologic evidence has suggested that HPV may be an independent risk factor for oropharyngeal cancers. Evidence now suggests HPV may modulate the malignancy process in some tobacco- and alcohol-induced oropharynx tumors, but might also be the primary oncogenic factor for inducing carcinogenesis among some non-smokers. More evidence, however, is needed regarding oral HPV prevalence among healthy adults to estimate risk. The goal of this study was to perform an HPV screening of normal healthy adults to assess oral HPV prevalence.

Methods

Healthy adult patients at a US dental school were selected to participate in this pilot study. DNA was isolated from saliva samples and screened for high-risk HPV strains HPV16 and HPV18 and further processed using qPCR for quantification and to confirm analytical sensitivity and specificity.

Results

Chi-square analysis revealed the patient sample was representative of the general clinic population with respect to gender, race and age (p < 0.05). Four patient samples were found to harbor HPV16 DNA, representing 2.6% of the total (n = 151). Three of the four HPV16-positive samples were from patients under 65 years of age and all four were female and Hispanic (non-White). No samples tested positive for HPV18.

Conclusions

The successful recruitment and screening of healthy adult patients revealed HPV16, but not HPV18, was present in a small subset. These results provide new information about oral HPV status, which may help to contextualize results from other studies that demonstrate oral cancer rates have risen in the US among both females and minorities and in some geographic areas that are not solely explained by rates of tobacco and alcohol use. The results of this study may be of significant value to further our understanding of oral health and disease risk, as well as to help design future studies exploring the role of other factors that influence oral HPV exposure, as well as the short- and long-term consequences of oral HPV infection.

An update on molecular diagnostics of squamous and salivary gland tumors of the head and neck

CONTEXT

Molecular testing in anatomic pathology is becoming standardized and can contribute valuable diagnostic, therapeutic, and prognostic information for the clinical management of patients. In head and neck pathology, recent advances in molecular testing have provided important targets in several different diagnostic areas, with particular emerging clinical applications in squamous and salivary gland pathology. In squamous mucosal-derived lesions, human papilloma virus has emerged as an important pathogenic etiology in a subset of oropharyngeal squamous cell carcinomas. Within the category of salivary gland tumors, 3 tumors have recently been recognized that contain oncogenic translocations.

OBJECTIVE

To describe the current state of information about the molecular alterations in squamous lesions and in salivary gland tumors of the head and neck.

DATA SOURCES

Published literature on squamous and salivary gland tumors of the head and neck.

CONCLUSIONS

The different approaches to identification of viral-associated tumors include assays using polymerase chain reaction, in situ hybridization, and immunohistochemistry. Most mucoepidermoid carcinomas harbor MECT1-MAML2 gene rearrangement. The MYB-NFIB translocations have recently been identified in adenoid cystic carcinomas. Finally, a newly described tumor of salivary gland, mammary analogue secretory carcinoma, harbors the ETV6-NTRK3 translocation. Although these translocations are just emerging as diagnostic targets, future roles may evolve as potential therapeutic targets.

Compound heterozygous loss of Ext1 and Ext2 is sufficient for formation of multiple exostoses in mouse ribs and long bones

Multiple Hereditary Exostoses (MHE) syndrome is caused by haploinsufficiency in Golgi-associated heparan sulfate polymerases EXT1 or EXT2 and is characterized by formation of exostoses next to growing long bones and other skeletal elements. Recent mouse studies have indicated that formation of stereotypic exostoses requires a complete loss of Ext expression, suggesting that a similar local loss of EXT function may underlie exostosis formation in patients. To further test this possibility and gain greater insights into pathogenic mechanisms, we created heterozygous Ext1(+/-) and compound Ext1(+/-)/Ext2(+/-) mice. Like Ext2(+/-) mice described previously (Stickens et al. Development 132:5055), Ext1(+/-) mice displayed rib-associated exostosis-like outgrowths only. However, compound heterozygous mice had nearly twice as many outgrowths and, more importantly, displayed stereotypic growth plate-like exostoses along their long bones. Ext1(+/-)Ext2(+/-) exostoses contained very low levels of immuno-detectable heparan sulfate, and Ext1(+/-)Ext2(+/-) chondrocytes, endothelial cells and fibroblasts in vitro produced shortened heparan sulfate chains compared to controls and responded less vigorously to exogenous factors such as FGF-18. We also found that rib outgrowths formed in Ext1(f/+)Col2Cre and Ext1(f/+)Dermo1Cre mice, suggesting that ectopic skeletal tissue can be induced by conditional Ext ablation in local chondrogenic and/or perichondrial cells. The study indicates that formation of stereotypic exostoses requires a significant, but not complete, loss of Ext expression and that exostosis incidence and phenotype are intimately sensitive to, and inversely related to, Ext expression. The data also indicate that the nature and organization of ectopic tissue may be influenced by site-specific anatomical cues and mechanisms.

Human papilloma virus associated head and neck cancer: A PCR based study

Head and neck cancers (HNC), 90% of which are squamous cell carcinomas (SCC), rank sixth among all malignancies worldwide and comprise 40-50% of the total number of malignancies in India. In addition to alcohol and tobacco usage, which is the major source of oral carcinogens, viruses such as human papilloma virus (HPV) may also contribute to development of the malignancy. The aim of this study was to identify the prevalence of HPV in head and neck cancers using material from metastatic site. A total of 111 cases of neck nodal metastases were included in this study. The primary was identified as oral cavity, oropharynx and nasopharynx. In a subset, the primary remained "unknown." Polymerase chain reaction was carried out to detect HPV DNA on the fine needle aspirates. HPV was detected in 32.4% cases. Maximum positivity was observed in metastases from primary in the oral cavity (47.1%) with tongue (55%), followed by oropharynx (25%) and nasopharynx (5%) cases. In the unknown primary group, HPV was detected in 52.9% cases. Study defines the association of HPV with HNC in population of northern India. There was varied association of HPV depending on site of primary tumor arising in mucosal surfaces of head and neck region.

The role of viruses in oral disease

The focus has traditionally been on bacteria and fungi when discussing microbiological aspects of oral disease. Viruses are probably more involved in diseases associated with the oral cavity than has been previously thought. The role of several viruses in ulceration is well known, but viruses of the herpes family may play a role in periodontitis, and papillomaviruses are probably involved in oral cancer. This review offers a brief introduction to virology before discussing the role of the more relevant viruses in oral disease. As to clinical application, it is concluded that the anti-herpes medication may, in some cases, be relevant in treating periodontitis, while papillomavirus vaccine would be expected to decrease the prevalence of oral cancer.

Detection of DNA by scraping the formalin-fixed paraffin-embedded tissue

BACKGROUND

Pakistan is a developing country and most of the research laboratories have limited required infrastructures for the diagnosis of cancer at molecular level. The polymerase chain reaction (PCR) on formalin-fixed paraffin-embedded tissues is becoming a popular procedure in the research centres. The study was conducted to introduce two new methods of DNA extraction for the PCR from formalin-fixed paraffin-embedded sections of surgical pathology specimens.

MATERIALS AND METHODS

Two methods of DNA detection were used. In method A the formalin-fixed tissues were grossed, proper sections were taken, processed in an automatic tissue processor, embedded in paraffin blocks, and microtomic sections were made. In method B, the procedure was the same until embedding in the paraffin blocks, after which the selected paraffin blocks were set on a black card paper (4 cm x 4 cm) and 1 mg of pure scraped tissue was obtained using a scalpel, manually without using microtone.

RESULTS

DNA was successfully extracted but point mutation of p53 gene was not seen in SCP while it was determined in 96 and 93.75 per cent cases of SCC by method A and method B respectively. There was no statistical difference in the results by both methods (P = 0.359).

CONCLUSION

Scraping of the tissue for DNA detection was a simple method and may be performed in any laboratory. The reliability, reproducibility, and quality assurance of the present results are consistent with the already established techniques of DNA extraction for PCR.