Molecular changes in oral cancer may reflect aetiology and ethnic origin

Unraveling the Genetic Web: H-Ras Expression and Mutation in Oral Squamous Cell Carcinoma-A Systematic Review

BACKGROUND

Oral squamous cell carcinoma (OSCC) is a commonly occurring malignancy with complex genetic alterations contributing to its development. The H-Ras, a proto-oncogene, becomes an oncogene when mutated and has been implicated in various cancers. This systematic review aims to research to what extent H-Ras expression and mutation contribute to the development and progression of OSCC, and how does this molecular alteration impacts the clinical characteristics and prognosis in patients with OSCC.

METHODS

A thorough electronic scientific literature search was carried out in PUBMED, SCOPUS, and GOOGLE SCHOLAR databases from 2007 to 2021. The search strategy yielded 120 articles. Following aggregation and filtering all results through our inclusion and exclusion criteria total 9 articles were included in our literature review. It has also been registered with PROSPERO (CRD42023485202).

RESULTS

It was found that mutations in the Ras gene commonly reported in hotspots at codons 12, 13, and 61 resulting in the activation of downstream signaling pathways causing abnormal and uncontrolled cell growth. This systematic review has shown an increased prevalence of H-Ras mutation in well-differentiated OSCC and also the prevalence of H-Ras mutation in individuals engaging in multiple risk behaviors, particularly chewing tobacco, demonstrated a significant association with a higher prevalence of H-Ras positivity.

CONCLUSION

This review sheds light on the prevalence of H-Ras mutations, their association with clinical characteristics, and their potential implications for OSCC prognosis. It also enhances our comprehension of the molecular mechanisms that underlie OSCC and paves the way for further research into targeted treatments based on H-Ras alterations.

Ki-67, CD105, and α-smooth muscle actin expression in oral squamous cell carcinoma corresponds with different forms of tobacco consumption habits

Background

Association with variety of etiological agents is one of the characteristic features of oral squamous cell carcinoma (OSCC). We hypothesized the existence of tobacco consumption habit-based heterogeneity in the immunohistochemical expression of carcinogenesis relevant molecular markers in OSCC. Hence, the present study was conducted to investigate the carcinogenesis relevant three commonly expressed markers (Ki-67, CD105, and α-smooth muscle acting [SMA]) in various forms of tobacco consumption habits in OSCC patients.

Materials and Methods

A total of 217 patients of OSCC were included in the study, and based on the habit, they were broadly categorized into tobacco lime (TL), TL and areca nut (TLAN), and areca nut (AN). Further, categorization was done on the basis of absence or presence of additional habit of smoking. Immunohistochemistry (IHC) was performed using Ki-67, CD105, and α-SMA markers on formalin-fixed paraffin-embedded tissues.

Results

TLAN (62.21%) was the most common habit noted in OSCC patient followed by TL (20.73%) and AN (15.20%). The additional habit of smoking was observed in 31.11% and 25.92% of TL and TLAN habits of OSCC patients, respectively. All the three markers (Ki-67, CD105, and α-SMA) showed statistically significant differences in the habit group such as TL, TLAN, and AN (P < 0.001). Although the expression of all the three markers was increased in TL as compared with TLAN, differences were not statistically significant. When these markers were compared in with and without smoking category, only TLAN with smoking and TLAN without smoking showed statistically significant differences in the expression of all three markers.

Conclusions

Ki-67 CD105 and α-SMA immunohistochemical expression in OSCC corresponds with different forms of tobacco consumption habits. Habit-related unique carcinogenesis events are reflected at IHC level thus providing proof of concept for future studies.

Worldwide Prevalence and Clinical Characteristics of RAS Mutations in Head and Neck Cancer: A Systematic Review and Meta-Analysis

In light of the development of RAS inhibitors, a reliable assessment of the prevalence of RAS mutations and their correlation with the clinical features of patients with HNC is crucially needed. This meta-analysis compiles the findings of 149 studies with over 8500 HNC patients and assesses the global prevalence of mutations in the HRAS, KRAS and NRAS genes. The available data were stratified according to geographical region, clinical features, and tumor characteristics, including human papillomavirus (HPV) infection status and tumor stage. In addition, the distribution of codon substitutions in each RAS gene was assessed. The estimated mutation rate is highest for HRAS (7%), followed by KRAS (2.89%) and NRAS (2.20%). HRAS prevalence in South Asia (15.28%) is twice as high as the global estimate. HRAS mutations are more prevalent in oral cavity and salivary gland tumors. In contrast, KRAS mutations are found more frequently in sinonasal tumors, and NRAS mutations are found chiefly in tumors of the nasopharynx. OR analyses show a significant association between HRAS mutations and a high tumor stage (OR=3.63). In addition, there is a significant association between HPV-positive status and KRAS mutations (OR=2.09). This study highlights RAS as a potential therapeutic target in certain subsets of HNC patients.

Outcome and treatment toxicity in east-indian versus white-canadian patients with oral cavity cancer following postoperative (chemo-)radiotherapy delivered under similar multidisciplinary care: A propensity-matched cohort study

PURPOSE

We compare clinical behaviour of East-Indians and White-Canadians with oral cavity squamous cell carcinoma (OSCC) treated at a Western institution within a uniform health care system.

MATERIALS/METHODS

Newly diagnosed OSCC patients who underwent postoperative (chemo-)radiotherapy (PORT/POCRT) between 2005 and 2017 were included. Data on ethnicity and other variables were extracted from patient-questionnaires, a prospective database and supplemented by chart review. Baseline characteristics were compared between East-Indian versus White-Canadian groups. A propensity-matched (1:1 ratio) of East-Indian versus White-Canadian cohorts was generated to compare locoregional control (LRC), distant control (DC), overall survival (OS), and acute and late toxicities.

RESULTS

A total of 53 East-Indian and 467 White-Canadian OSCC patients were identified. Compared to White-Canadians, East-Indian patients were younger, had less exposure to smoking and alcohol (p < 0.001), but more chewed betel (areca) nut /tobacco (43% vs 0.2%, p < 0.001). Buccal/retromolar-trigone/lower gingiva primaries were more common in East-Indians (49% vs 25%, p < 0.001). Median follow-up was 5.0 years. Propensity-score paired analysis revealed inferior 3-year LRC (68% vs 81%, p = 0.030), non-significantly lower OS (61% vs 75%, p = 0.257), but similar DC (81% vs 87%, p = 0.428) in East-Indian versus White-Canadian patients. Actuarial rate of toxicities was higher in East-Indians vs White-Canadians: acute toxicity at 6 weeks: 47% vs 30%, p = 0.012; chronic trismus at 5-years: 16% vs 2%, p = 0.013.

CONCLUSION

East-Indian OSCC patients have a greater betel nut/ chewable tobacco exposure compared to White-Canadians and a different distribution of OSCC sites. Propensity-matched cohort analysis showed lower LRC and higher toxicities in East-Indian OSCC patients, suggesting a complicated interaction between genetic/biological and life-style factors.

Association of Immigration Status and Chinese and South Asian Ethnicity With Incidence of Head and Neck Cancer

Importance

Head and neck cancer (HNC) incidence varies worldwide, although it remains one of the most common cancers among those of East Asian and South Asian ethnicity.

Objective

To determine the association of Chinese and South Asian ethnicity, independent of immigration status, with HNC incidence.

Design, Setting, and Participants

This was a retrospective population-based matched cohort study that examined data collected between 1994 and 2017 in Ontario, Canada. Data were analyzed between July 2019 and March 2020. Individuals who immigrated to Canada between 1985 and 2017 were classified as immigrants, whereas Canadian-born individuals and those who immigrated prior to 1985 were classified as long-standing residents. Two separate, matched cohorts were created: an immigration cohort, consisting of immigrants and long-standing residents hard matched on age and sex, and an ethnicity cohort, where participants were further matched on ethnicity (Chinese, South Asian, or non-Chinese/non-South Asian).

Exposures

Chinese ethnicity, South Asian ethnicity, and immigration status.

Main Outcomes and Measures

Patients newly diagnosed with primary HNC were captured in both the immigration and the ethnicity cohorts. Cause-specific hazard models were used to estimate the association of immigration status and ethnicity with HNC incidence.

Results

In the immigration cohort, 3 328 434 matched individuals (mean [SD] age, 36.73 [13.46] years; 52.8% female) were followed, across which 3173 unique HNC diagnoses were made. The hazard ratio (HR) for a new diagnosis of oropharynx cancer was lower in immigrants compared with long-standing residents (HR, 0.26 [95% CI, 0.22-0.31]). In the ethnicity cohort, after adjusting for age, sex, rurality, and deprivation, the rate of HNC diagnosis was higher for Chinese individuals (HR, 1.49 [95% CI, 1.36-1.64]) and South Asian individuals (HR, 1.29 [95% CI, 1.14-1.45]), although it was lower for immigrants (HR, 0.48 [95% CI, 0.44-0.52]) when compared with non-Chinese and non-South Asian individuals. There was no difference in the incidence of nasopharynx cancer when comparing immigrants and long-standing residents of Chinese ethnicity.

Conclusions and Relevance

Immigration status appears to offer a protective effect against a diagnosis of HNC. Chinese and South Asian ethnic groups may experience higher HNC incidence when compared with the general Ontario population.

Genetically-defined novel oral squamous cell carcinoma cell lines for the development of molecular therapies

Emerging biological and translational insights from large sequencing efforts underscore the need for genetically-relevant cell lines to study the relationships between genomic alterations of tumors, and therapeutic dependencies. Here, we report a detailed characterization of a novel panel of clinically annotated oral squamous cell carcinoma (OSCC) cell lines, derived from patients with diverse ethnicity and risk habits. Molecular analysis by RNAseq and copy number alterations (CNA) identified that the cell lines harbour CNA that have been previously reported in OSCC, for example focal amplications in 3q, 7p, 8q, 11q, 20q and deletions in 3p, 5q, 8p, 18q. Similarly, our analysis identified the same cohort of frequently mutated genes previously reported in OSCC including TP53, CDKN2A, EPHA2, FAT1, NOTCH1, CASP8 and PIK3CA. Notably, we identified mutations (MLL4, USP9X, ARID2) in cell lines derived from betel quid users that may be associated with this specific risk factor. Gene expression profiles of the ORL lines also aligned with those reported for OSCC. By focusing on those gene expression signatures that are predictive of chemotherapeutic response, we observed that the ORL lines broadly clustered into three groups (cell cycle, xenobiotic metabolism, others). The ORL lines noted to be enriched in cell cycle genes responded preferentially to the CDK1 inhibitor RO3306, by MTT cell viability assay. Overall, our in-depth characterization of clinically annotated ORL lines provides new insight into the molecular alterations synonymous with OSCC, which can facilitate in the identification of biomarkers that can be used to guide diagnosis, prognosis, and treatment of OSCC.

Head and neck cancers in India

Head and neck cancers constitute a third of the cancer burden in India. These cancers have unique patient characteristics, presentation, and etiological differences from those in the West. Socioeconomic constraints, large patient population, scarcity of trained health workers, and inadequate infrastructure are major challenges faced in the management of these cancers. Despite these constraints, patients are treated with evidence based guidelines that are tailored to the local scenario.

The Role of TGF-β in Epithelial Malignancy and its Relevance to the Pathogenesis of Oral Cancer (Part II)

The role of transforming growth factor-β (TGF-β) in epithelial malignancy is complex, but it is becoming clear that, in the early stages of carcinogenesis, the protein acts as a potent tumor suppressor, while later, TGF-β can function to advance tumor progression. We review the evidence to show that the pro-oncogenic functions of TGF-β are associated with (1) a partial loss of response to the ligand, (2) defects of components of the TGF-β signal transduction pathway, (3) over-expression and/or activation of the latent complex, (4) epithelial-mesenchymal transition, and (5) recruitment of signaling pathways which act in concert with TGF-β to facilitate the metastatic phenotype. These changes are viewed in the context of what is known about the pathogenesis of oral cancer and whether this knowledge can be translated into the development of new therapeutic modalities.

Squamous cell carcinoma of tongue and buccal mucosa: clinico-pathologically different entities

The objective of this study was to examine the clinical and pathological features of squamous cell carcinoma of the Tongue and Buccal Mucosa and understand their differences. This is a retrospective analysis of prospectively collected data of 735 patients with squamous cell carcinoma of the tongue and 665 cases of carcinoma of the buccal mucosa treated by surgery at our hospital. Statistical analysis was done to examine clinical and pathological differences between carcinoma of the tongue and the buccal mucosa with regards to age, gender, clinical T stage/N stage, pathological T stage/N stage, overall stage, grade, thickness, perinodal extension (PNE), lymphovascular emboli (LVE) and perineural invasion (PNI). Statistically significant differences were found for factors like age (p < 0.001), gender (p < 0.001), clinical T staging (p < 0.001) and pathological stage (p < 0.001), grade of tumor (p < 0.001) and perineural invasion (p < 0.001) between carcinoma of the tongue and the buccal mucosa. Forty-eight percent patients in either subsite had pathologically proven node negative necks (pN0, p = 0.88). Multivariate analysis for occult nodal metastases revealed that predictive factors were different for the two subsites. There are significant differences between cancers of the tongue and buccal mucosa for various clinical and pathological factors. This may be a reflection of the underlying differences in their causation and pathophysiology. Squamous cell carcinoma in these two subsites should therefore be regarded as clinico-pathologically distinct entities.

Quantitative Assessment of Tumor Associated Macrophages in Head and Neck Squamous Cell Carcinoma Using CD68 Marker: An Immunohistochemical Study

INTRODUCTION

Oral Squamous Cell Carcinoma (OSCC) is one of the most prevalent cancers in India. Clear evidence regarding inflammation being an etiological factor of cancer was found only in the last few decades. A major inflammatory component in the tumor tissue is Tumor-Associated Macrophages (TAMs). The CD68 antibody is a marker for staining TAMs.

AIM

The aim of this study is to quantify the macrophage count in healthy oral mucosa and OSCC and comparing TAMs in different histopathological grades of OSCC immunohistochemically.

MATERIALS AND METHODS

Thirty archival specimens of OSCC patients and 10 healthy biopsy samples were collected. Immunohistochemical staining was done using a CD68 marker. Statistical analysis was done using Kruskal-Wallis ANOVA and Mann-Whitney U test.

RESULTS

Comparing CD68 expression in various study groups showed a significant difference (p=0.000). The pair-wise analysis showed different grades of OSCC, which differed significantly for CD68 expression from the normal oral mucosa.

CONCLUSION

The most significant cells present in tumor stroma are TAMs, which remain in close proximity to neoplastic cells and interact with them via several chemical mediators, which may serve to increase the invasiveness of the malignant epithelium. Dense infiltration of TAMs adjacent to tumor cells and islands vividly implies their role in tumor progression.

Integrating genomics in head and neck cancer treatment: Promises and pitfalls

Head and neck squamous cell carcinomas (HNSCC) represent a multifactorial disease of poor prognosis. They have lagged behind other cancers in terms of personalized therapy. With expansion and high throughput sequencing methods, recent landmark exonic studies and Cancer Genome Atlas data have identified genes relevant to carcinogenesis and cancer progression. Mutational profiles and rates vary widely depending on exposure to carcinogens, anatomic subsites and human papilloma virus (HPV) infection. Tumors may exhibit specific, tissue-specific, not exclusively HPV-related, gene alterations, such those observed in oral cavity cancers in Asia or Occident. Except for the PI3K pathway, the rate of mutations in HPV+ cancers is much lower than in tobacco/alcohol-related cancers. Somatic driver mutation analyses show that relatively few driver genes are druggable in HNSCC and that tumor suppressor gene alterations prevail. More mature for therapeutic applications is the oncogenic PI3K pathway, with preclinical human xenograft models suggesting that PI3KCA pathway mutations may be used as predictive biomarkers and clinical data showing efficacy of mTOR/Akt inhibitors. Therapeutic guidance, to date, relies on classical histoprognostic factors, anatomic subsite and HPV status, with integration of hierarchized supervised mutational profiling to provide additional therapeutic options in advanced HNSCC in a near future. Unsupervised controlled genomic analyses remain necessary to unravel potentially relevant genes.

Genetic alterations of chromosome 8 genes in oral cancer

The clinical relevance of DNA copy number alterations in chromosome 8 were investigated in oral cancers. The copy numbers of 30 selected genes in 33 OSCC patients were detected using the multiplex ligation-dependent probe amplification (MLPA) technique. Amplifications of the EIF3E gene were found in 27.3% of the patients, MYC in 18.2%, RECQL4 in 15.2% and MYBL1 in 12.1% of patients. The most frequent gene losses found were the GATA4 gene (24.2%), FGFR1 gene (24.2%), MSRA (21.2) and CSGALNACT1 (12.1%). The co-amplification of EIF3E and RECQL4 was found in 9% of patients and showed significant association with alcohol drinkers. There was a significant association between the amplification of EIF3E gene with non-betel quid chewers and the negative lymph node status. EIF3E amplifications did not show prognostic significance on survival. Our results suggest that EIF3E may have a role in the carcinogenesis of OSCC in non-betel quid chewers.

Defining the genomic landscape of head and neck cancers through next-generation sequencing

Next-generation sequencing (NGS) has revolutionized the field of genomics and improved our understanding of cancer biology. Advances have been achieved by sequencing tumor DNA and using matched normal DNA to filter out germ line variants to identify cancer-specific changes. The identification of high incidences of activating mutations in head and neck squamous cell carcinoma (HNSCC) amenable to drug targeting has been made, with clear distinctions between the mutational profile of HPV-positive and HPV-negative tumors. This wealth of new understanding undoubtedly ameliorates our understanding of HNSCC cancer biology and elucidates clear targets for drug targeting which will guide future personalized medicine.

Head and neck cancers in developing countries

Head and neck cancers are the most common cancers in developing countries, especially in Southeast Asia. Head and neck cancers are more common in males compared to females. This is mainly attributed to tobacco, areca nut, alcohol, etc. Oral cancers are most common amongst all head and neck squamous cell cancers (HNSCC). HNSCC in the developing world differ from those in the Western world in terms of age, site of disease, etiology, and molecular biology. Poverty, illiteracy, advanced stage at presentation, lack of access to health care, and poor treatment infrastructure pose a major challenge in management of these cancers. The annual GDP (gross domestic product) spent on health care is very low in developing countries compared to the developed countries. Cancer treatment leads to a significant financial burden on the cancer patients and their families. Several health programs have been implemented to curb this rising burden of disease. The main aims of these health programs are to increase awareness among people regarding tobacco and to improve access to health care facilities, early diagnosis, treatment, and palliative care.

An analysis of the epidemiological and etiological factors of oral tumors of young adults in a Central-Eastern European population

The etiology of tumors in young age is not precisely known yet, but studies on the topic generally agree that in this group of patients the traditionally known behavioural risk factors (tobacco and alcohol abuse) play no or a significantly less important role. Oral squamous cell carcinoma occurring at a young age is a topic of utmost importance that is extensively and intensively researched as, while the overall incidence of oral cancer is decreasing worldwide, that of squamous cell carcinoma diagnosed in young adults is steadily increasing. The present article aims at presenting the main questions and characteristics of tumors in young adults in Central-Eastern Europe and in developed West European countries as contrasted to tumors found in middle aged and elderly patients. Factors influencing the development of oral cancer include regulatory factors of the cell cycle, the inherited vulnerability of the genetic code of certain proteins and the presence of HPV infection with an oncogenic genotype. The connections of HPV infection and genetic damages are studied intensively. It is known that the prevalence of oral HPV infections is growing with a background of potentially changing sexual habits. It is debated, however, whether smoking and alcohol consumption could have a connection to HPV associated oral cancer and whether the spread of HPV in itself could be an explanation for the growing occurrence of young-age tumors. There is no consensus in the literature as to the prognostic significance of age. Some research groups have found a better life expectancy for young patients, while other authors found a worse prognosis for these patients. It is known that the prognosis of head and neck tumors, the prevalence of HPV infections as well as genetic mutations show regional and ethnic variations. This might be explained by differences in the degree of development of a preventive system, in the quality of care and in the attitudes of young patients towards visiting a doctor. The study is made difficult by incomparable patient selection criteria as well as by the question of the intraoral localisation of tumors as an independent risk factor.

The landscape of alternative splicing in buccal mucosa squamous cell carcinoma

OBJECTIVES

Alternative splicing (AS) is a key regulatory mechanism in the process of protein synthesis generating transcriptome and proteome diversity. In this study, we attempted to identify alternative splicing in a pair of BMSCC cancer and adjacent normal tissue using RNAseq datasets and also assessed the potential of these datasets to provide quantitative measurements for alternative splicing levels.

MATERIALS AND METHODS

We performed high-throughput sequencing of buccal mucosal cancer and healthy tissue cDNA library which resulted in a transcriptome map of BMSCC cancer. RNAseq analysis was performed to assess alternative splicing complexity in cancer tissue and to search splice junction sequences that represent candidate 'new' splicing events. The splice junctions were predicted by SpliceMap software and putative assembled transcripts validated using the RT-PCR. We also analyzed the coding potential of alternative spliced candidate by HMMER.

RESULTS

We detected a total of 11 novel splice junctions derived mostly from alternate 5' splice site; including two of them which contained new translation initiation sites (TISs). We have identified novel IgG pseudogene and a fusion transcript of MEMO1 and RPS9, which were further confirmed by PCR from genomic DNA. We also found novel putative long non-coding RNA (lncRNA), which is antisense to SPINK5 gene. The coding potential of these AS variants revealed that alternative splicing caused premature termination, insertion/deletion of amino acid (s) or formation of novel N-terminus.

CONCLUSIONS

Differential splicing of these novel AS variants between cancer and adjacent normal tissue suggests their involvement in BMSCC cancer development and progression.

Lessons learned from next-generation sequencing in head and neck cancer

Scientific innovation has enabled whole exome capture and massively parallel sequencing of cancer genomes. In head and neck cancer, next-generation sequencing has granted us further understanding of the mutational spectrum of squamous cell carcinoma. As a result of these new technologies, frequently occurring mutations were identified in NOTCH1, a gene that had not previously been implicated in head and neck cancer. The current review describes the most common mutations in head and neck cancer: TP53, NOTCH1, HRAS, PIK3CA, and CDKN2A. Emphasis is placed on the involved cellular pathways, clinical correlations, and potential therapeutic interventions. Additionally, the implications of human papillomavirus on mutation patterns are discussed.

Growth hormone-releasing hormone receptor splice variant 1 is frequently expressed in oral squamous cell carcinomas

The expression of growth hormone-releasing hormone (GHRH) splice variant 1 (SV1) receptor in neoplastic lesions of the oral cavity was assessed. The sensitivity of HaCaT keratinocytes to GHRH analogs was also evaluated. Thirty-three benign precancerous oral lesions and 27 squamous cell carcinomas of the oral cavity were evaluated by immunohistochemistry for SV1 expression. SV1 expression in HaCaT keratinocytes was assessed by western blot. HaCaT proliferation was evaluated by cell counting. Anti-SV1 immunoreactivity was detected in only 9% (three of 33) precancerous lesions (one hyperplasia and two dysplasias), while 44% (12 of 27) carcinomas were positive for SV1 (p<0.002). GHRH(1-29)NH(2) and GHRH agonist JI-38 stimulated HaCaT proliferation in vitro, and this effect was blocked by GHRH antagonists. These results indicate that SV1 expression may be associated with the transition of precancerous lesions to carcinomas of the oral epithelium. GHRH antagonists may be useful for the management of the disease.

Ras oncogenes in oral cancer: the past 20 years

Oral squamous cell carcinoma (OSCC) of head and neck is associated with high morbidity and mortality in both Western and Asian countries. Several risk factors for the development of oral cancer are very well established, including tobacco chewing, betel quid, smoking, alcohol drinking and human papilloma virus (HPV) infection. Apart from these risk factors, many genetic factors such as oncogenes, tumor suppressor genes and regulatory genes are identified to involve in oral carcinogenesis with these risk factors dependent and independent manner. Ras is one of the most frequently genetically deregulated oncogene in oral cancer. In this review, we analyze the past 22years of literature on genetic alterations such as mutations and amplifications of the isoforms of the ras oncogene in oral cancer. Further, we addressed the isoform-specific role of the ras in oral carcinogenesis. We also discussed how targeting the Akt and MEK, downstream effectors of the PI3K/Akt and MAPK pathways, respectively, would probably pave the possible molecular therapeutic target for the ras driven tumorigenesis in oral cancer. Analysis of these ras isoforms may critically enlighten specific role of a particular ras isoform in oral carcinogenesis, enhance prognosis and pave the way for isoform-specific molecular targeted therapy in OSCC.

Relationship between p53 overexpression, human papillomavirus infection, and lifestyle in Indian patients with head and neck cancers

Exposure to pollutants in the environment, tobacco and alcohol consumption, poor oral hygiene and opportunistic viral infections are important aetiological factors in head and neck cancers. In this study, we evaluate the complex interrelationships between these factors and molecular events such as p53 overexpression in causation of head and neck cancers. Tissue samples from 110 patients with histopathologically confirmed carcinoma of head and neck were analyzed from our tissue biorepository with patient consent. Data pertaining to their dietary habits, tobacco and alcohol consumption were abstracted. P53 overexpression was analysed by immunohistochemistry and HPV (high-risk genotype) were studied by Chromogenic in situ Hybridization using an ultra sensitive DNA probe. Chi-square analysis was done to determine relationships between proportions of dependent and independent variables. Bivariate relationships were determined between these variables using Spearman's rank correlation. Linear regression analysis was used to determine the best predictor variable influencing p53 expression. Tobacco consumption especially smoking cigarettes and all forms of tobacco consumption put together and HPV infection significantly influenced p53 overexpression. Forty-five percent of the studied cohort was positive for HPV. Regression analysis showed interaction between tobacco and HPV infection to be a primary predictor (β = 0.31, p = 0.02) for p53 expression. Tobacco in any form: chewing, smoking and snuffing, along with HPV infection is significantly associated with p53 overexpression. There is a high prevalence of HPV infection (45%) in Indian patients suggesting its possible role in the aetiology of head and neck cancer.

Myc, Aurora Kinase A, and mutant p53(R172H) co-operate in a mouse model of metastatic skin carcinoma

Clinical observations, as well as data obtained from the analysis of genetically engineered mouse models, firmly established the gain-of-function (GOF) properties of certain p53 mutations. However, little is known about the underlying mechanisms. We have used two independent microarray platforms to perform a comprehensive and global analysis of tumors arising in a model of metastatic skin cancer progression, which compares the consequences of a GOF p53(R172H) mutant vs p53 deficiency. DNA profiling revealed a higher level of genomic instability in GOF vs loss-of-function (LOF) p53 squamous cell carcinomas (SCCs). Moreover, GOF p53 SCCs showed preferential amplification of Myc with a corresponding increase in its expression and deregulation of Aurora Kinase A. Fluorescent in situ hybridization confirmed amplification of Myc in primary GOF p53 SCCs and its retention in metastatic tumors. We also identified by RNA profiling distinct gene expression profiles in GOF p53 tumors, which included enriched integrin and Rho signaling, independent of tumor stage. Thus, the progression of GOF p53 papillomas to carcinoma was marked by the acquisition of epithelial-to-mesenchymal transition and metastatic signatures. In contrast, LOF p53 tumors showed enrichment of genes associated with cancer proliferation and chromosomal instability. Collectively, these observations suggest that genomic instability has a prominent role in the early stages of GOF p53 tumor progression (that is, papillomas), whereas it is implicated at a later stage in LOF p53 tumors (that is, SCCs). This model will allow us to identify specific targets in mutant p53 SCCs, which may lead to the development of new therapeutic agents for the treatment of metastatic SCCs.

Genomic profiling of advanced-stage oral cancers reveals chromosome 11q alterations as markers of poor clinical outcome

Identifying oral cancer lesions associated with high risk of relapse and predicting clinical outcome remain challenging questions in clinical practice. Genomic alterations may add prognostic information and indicate biological aggressiveness thereby emphasizing the need for genome-wide profiling of oral cancers. High-resolution array comparative genomic hybridization was performed to delineate the genomic alterations in clinically annotated primary gingivo-buccal complex and tongue cancers (n = 60). The specific genomic alterations so identified were evaluated for their potential clinical relevance. Copy-number changes were observed on chromosomal arms with most frequent gains on 3q (60%), 5p (50%), 7p (50%), 8q (73%), 11q13 (47%), 14q11.2 (47%), and 19p13.3 (58%) and losses on 3p14.2 (55%) and 8p (83%). Univariate statistical analysis with correction for multiple testing revealed chromosomal gain of region 11q22.1–q22.2 and losses of 17p13.3 and 11q23–q25 to be associated with loco-regional recurrence (P = 0.004, P = 0.003, and P = 0.0003) and shorter survival (P = 0.009, P = 0.003, and P 0.0001) respectively. The gain of 11q22 and loss of 11q23-q25 were validated by interphase fluorescent in situ hybridization (I-FISH). This study identifies a tractable number of genomic alterations with few underlying genes that may potentially be utilized as biological markers for prognosis and treatment decisions in oral cancers.

Betel-derived alkaloid up-regulates keratinocyte alphavbeta6 integrin expression and promotes oral submucous fibrosis

Oral submucous fibrosis (OSF) is a premalignant, fibrosing disorder of the mouth, pharynx, and oesophagus, with a malignant transformation rate of 7-13%. OSF is strongly associated with areca (betel) nut chewing and worldwide, over 5 million people are affected. As αvβ6 integrin is capable of promoting both tissue fibrosis and carcinoma invasion, we examined its expression in fibroepithelial hyperplasia and OSF. αvβ6 was markedly up-regulated in OSF, with high expression detected in 22 of 41 cases (p < 0.001). We investigated the functional role of αvβ6 using oral keratinocyte-derived cells genetically modified to express high αvβ6 (VB6), and also NTERT-immortalized oral keratinocytes, which express low αvβ6 (OKF6/TERT-1). VB6 cells showed significant αvβ6-dependent activation of TGF-β1, which induced transdifferentiation of oral fibroblasts into myofibroblasts and resulted in up-regulation of genes associated with tissue fibrosis. These experimental in vitro findings were confirmed using human clinical samples, where we showed that the stroma of OSF contained myofibroblasts and that TGF-β1-dependent Smad signalling was detectable both in keratinocytes and in myofibroblasts. We also found that arecoline, the major alkaloid of areca nuts, up-regulated keratinocyte αvβ6 expression. This was modulated through the M(4) muscarinic acetylcholine receptor and was suppressed by the M(4) antagonist, tropicamide. Arecoline-dependent αvβ6 up-regulation promoted keratinocyte migration and induced invasion, raising the possibility that this mechanism may support malignant transformation. Over 80% of OSF-related oral cancers examined had moderate/high αvβ6 expression. These data suggest that the pathogenesis of OSF may be epithelial-driven and involve arecoline-dependent up-regulation of αvβ6 integrin.

Mutational analyses of the BRAF, KRAS, and PIK3CA genes in oral squamous cell carcinoma

OBJECTIVES

The development of oral squamous cell carcinoma (OSCC) is a complex, multistep process. To date, numerous oncogenes and tumor-suppressor genes have been implicated in oral carcinogenesis. Of particular interest in this regard are genes involved in cell cycling and apoptosis, such BRAF, KRAS, and PIK3CA genes.

STUDY DESIGN

Mutations of BRAF, KRAS, and PIK3CA were evaluated by direct genomic sequencing of exons 1 of KRAS, 11 and 15 of BRAF, and 9 and 20 of PIK3CA in OSCC specimens.

RESULTS

Both BRAF and KRAS mutations were detected with a mutation frequency of 2% (1/42). PIK3CA mutations were detected at 3% (1/35).

CONCLUSIONS

This is the first report implicating BRAF mutation in OSCC. Our study supports that mutations in the BRAF, KRAS, and PIK3CA genes make at least a minor contribution to OSCC tumorigenesis, and pathway-specific therapies targeting these 2 pathways should be considered for OSCC in a subset of patients with these mutations.

Cancer genes alterations and HPV infection in oral squamous cell carcinoma

The aim of this study was to gain a better understanding of cancer genes contributing to oral squamous cell (OSCC) development and progression and correlate genetic changes to clinical parameters. Human papilloma virus (HPV) 16 detection is also included in the study. 60 samples of OSCC were analysed for c-erbB2 and c-myc amplification by dPCR, H-ras and p53 point mutations by PCR/SSCP. HPV was detected via amplification of its E1 and E6 genes. c-erbB2 was altered in 45%, c-myc in 35%, H-ras in 22% and p53 in 60% of samples. HPV was detected in 10% of cases. The frequency of p53 gene mutations showed a statistically significant association with tumour stage. Patients with c-erbB2 and H-ras alterations had lower survival than patients without these alterations. The number of detected genetic changes was remarkable but statistical association with tumour natural history was poor, indicating high clonal heterogeneity and multiple pathways of carcinogenesis.

Glycogen synthase kinase 3 beta: can it be a target for oral cancer

Despite progress in treatment approaches for oral cancer, there has been only modest improvement in patient outcomes in the past three decades. The frequent treatment failure is due to the failure to control tumor recurrence and metastasis. These failures suggest that new targets should be identified to reverse oral epithelial dysplastic lesions. Recent developments suggest an active role of glycogen synthase kinase 3 beta (GSK3 β) in various human cancers either as a tumor suppressor or as a tumor promoter. GSK3β is a Ser/Thr protein kinase, and there is emerging evidence that it is a tumor suppressor in oral cancer. The evidence suggests a link between key players in oral cancer that control transcription, accelerated cell cycle progression, activation of invasion/metastasis and anti-apoptosis, and regulation of these factors by GSK3β. Moreover, the major upstream kinases of GSK3β and their oncogenic activation by several etiological agents of oral cancer support this hypothesis. In spite of all this evidence, a detailed analysis of the role of GSK3β in oral cancer and of its therapeutic potential has yet to be conducted by the scientific community. The focus of this review is to discuss the multitude of roles of GSK3β, its possible role in controlling different oncogenic events and how it can be targeted in oral cancer.

Infiltrating macrophage count: a significant predictor for the progression and prognosis of oral squamous cell carcinomas in Taiwan

BACKGROUND

Infiltrating macrophage count (IMC) is found to correlate with the progression and prognosis of many human cancers.

METHODS

This study used immunohistochemistry to measure the IMC (macrophages/high-power field [HPF]) in 92 specimens of oral squamous cell carcinoma (OSCC).

RESULTS

A significantly increased IMC was found in OSCCs with larger tumor size, positive lymph node metastasis, more advanced clinical stages, or recurrence (all ps < .05). Kaplan-Meier survival analysis found that OSCC patients with IMC >196 macrophages/HPF had a significantly shorter disease-free (p = .001, log-rank test) or overall survival (p < .001, log-rank test) than OSCC patients with IMC <196 macrophages/HPF. Multivariate Cox regression analyses showed that IMC >196 macrophages/HPF was an independent predictor for poor disease-free (p = .005) and overall survival of patients with OSCC (p = .015).

CONCLUSIONS

The IMC can predict the progression and prognosis of OSCCs in Taiwan.

Barriers to early detection and treatment of head and neck squamous cell carcinoma in African American men

BACKGROUND

African Amercians afflicted with head and neck squamous cell carcinoma (HNSCC) have a strikingly worse survival than do whites. One apparent cause is an advanced stage of presentation in African Americans. This study was designed to identify barriers to early treatment among African American men.

METHODS

Twenty-four African American male HNSCC survivors completed structured interviews. Interviewers elicited the participants' experiences from symptom recognition to receiving definitive care.

RESULTS

Most participants were seen with advanced-stage HNSCC. Overall, 10% experienced barriers to obtaining early medical care, though 30% were hesitant to seek care due to perceived barriers. Definitive treatment began for 81% within 3 months of initial care seeking.

CONCLUSION

Once participants sought care, most of them received definitive treatment within a reasonable time frame. To explain the advanced stage at presentation, either tumor growth rate was extremely rapid or participants sought care when the tumor was quite advanced. The themes suggested by this elicitation study require further validation.

A genetic variant of Aurora kinase A promotes genomic instability leading to highly malignant skin tumors

Aurora kinase A (Aurora-A) belongs to a highly conserved family of mitotis-regulating serine/threonine kinases implicated in epithelial cancers. Initially we examined Aurora-A expression levels at different stages of human skin cancer. Nuclear Aurora-A was detected in benign lesions and became more diffused but broadly expressed in well and poorly differentiated squamous cell carcinomas (SCC), indicating that Aurora-A deregulation may contribute to SCC development. To mimic the overexpression of Aurora-A observed in human skin cancers, we established a gene-switch mouse model in which the human variant of Aurora-A (Phe31Ile) was expressed in the epidermis upon topical application of the inducer RU486 (Aurora-AGS). Overexpression of Aurora-A alone or in combination with the tumor promoter 12-O-tetradecanoylphorbol 13-acetate (TPA), did not result in SCC formation in Aurora-AGS mice. Moreover, Aurora-A overexpression in naive keratinocytes resulted in spindle defects in vitro and marked cell death in vivo, suggesting that the failure of Aurora-A to initiate tumorigenesis was due to induction of catastrophic cell death. However, Aurora-A overexpression combined with exposure to TPA and the mutagen 7,12-dimethylbenz(a)anthracene accelerated SCC development with greater metastatic activity than control mice, indicating that Aurora-A cannot initiate skin carcinogenesis but rather promotes the malignant conversion of skin papillomas. Further characterization of SCCs revealed centrosome amplification and genomic alterations by array CGH analysis, indicating that Aurora-A overexpression induces a high level of genomic instability that favors the development of aggressive and metastatic tumors. Our findings strongly implicate Aurora-A overexpression in the malignant progression of skin tumors and suggest that Aurora-A may be an important therapeutic target.

Detection of two novel mutations and relatively high incidence of H-RAS mutations in Vietnamese oral cancer

Oral squamous cell carcinoma is the sixth most common cancer in the world and the seventh most common cancer in Vietnam. The RAS and PI3K-AKT signaling pathways play an important role in oral carcinogenesis. Our previous study on PI3K signaling pathway showed the absence of PIK3CA and PTEN gene mutations in Vietnamese oral cancer. We thus hypothesized that the RAS could be more likely activated as an upstream effector. However, the status of RAS mutations in Vietnamese oral cancer had not been studied. In the present study, Fifty six primary tumor DNA samples were screened for mutations of hot spots in exons 1 and 2 of H-RAS and a part of the samples for exon 7 of ERK2 gene in which we previously reported a mutation in an OSCC cell line. The H-RAS mutations were detected in 10 of 56 tumors (18%). Two novel mutations were found, one was an insertion of three nucleotides (GGC) between codons 10 and 11 resulting in in-frame insertion of glycine (10(Gly)11) and the other was a missense mutation in codon 62 (GAG>GGG). We also found T81C single nucleotide polymorphism in 12 of 56 tumors (22%) and there was no mutation in exon 7 of ERK2 gene. The H-RAS mutation incidence showed significant association with advanced stages of the tumor and also with well-differentiated tumor grade. Our study is the first to report H-RAS mutation from Vietnamese ethnicity, with two novel mutations and relatively high incidence of H-RAS mutations. The results suggest that RAS is an important member in the PI3K-AKT signaling and could play an important role in the tumorigenesis of oral carcinoma.

Construction of oncogenetic tree models reveals multiple pathways of oral cancer progression

Oral cancer develops and progresses by accumulation of genetic alterations. The interrelationship between these alterations and their sequence of occurrence in oral cancers has not been thoroughly understood. In the present study, we applied oncogenetic tree models to comparative genomic hybridization (CGH) data of 97 primary oral cancers to identify pathways of progression. CGH revealed the most frequent gains on chromosomes 8q (72.4%) and 9q (41.2%) and frequent losses on 3p (49.5%) and 8p (47.5%). Both mixture and distance-based tree models suggested multiple progression pathways and identified +8q as an early event. The mixture model suggested two independent pathways namely a major pathway with -8p and a less frequent pathway with +9q. The distance-based tree identified three progression pathways, one characterized by -8p, another by -3p and the third by alterations +11q and +7p. Differences were observed in cytogenetic pathways of node-positive and node-negative oral cancers. Node-positive cancers were characterized by more non-random aberrations (n = 11) and progressed via -8p or -3p. On the other hand, node-negative cancers involved fewer non-random alterations (n = 6) and progressed along -3p. In summary, the tree models for oral cancers provided novel information about the interactions between genetic alterations and predicted their probable order of occurrence.

Gene expression in human oral squamous cell carcinoma is influenced by risk factor exposure

Oral squamous cell carcinoma (OSCC) is a world health problem and is associated with exposure to different risk factors. In the west, smoking and alcohol consumption are considered to be the main risk factors whilst in India and southeast Asia, betel quid (BQ) chewing is predominant. In this study, we compared the gene expression patterns of oral cancers associated with BQ chewing to those caused by smoking using Affymetrix microarrays. We found that 281 genes were differentially expressed between OSCC and normal oral mucosa regardless of aetiological factors including MMP1, PLAU, MAGE-D4, GNA12, IFITM3 and NMU. Further, we identified 168 genes that were differentially expressed between the BQ and smoking groups including CXCL-9, TMPRSS2, CA12 and RNF24. The expression of these genes was validated using qPCR using independent tissue samples. The results demonstrate that whilst common genes/pathways contribute to the development of oral cancer, there are also other gene expression changes that are specific to certain risk factors. The findings suggest that different carcinogens activate or inhibit specific pathways during cancer development and progression. These unique gene expression profiles should be taken into consideration when developing biomarkers for future use in prognostic or therapeutic applications.

Rates of cutaneous metastases from different internal malignancies: experience from a Taiwanese medical center

BACKGROUND

Previous reports regarding the rates at which various internal tumors metastasize to the skin have been limited and have only included the Caucasian population. Moreover, the mechanisms that predispose certain internal malignancies to metastasize to the skin have rarely been discussed in the scientific literature.

OBJECTIVES

We determined the frequencies with which various internal malignancies metastasize to the skin in patients from a Taiwanese medical center. We also evaluated whether expressions of chemokine receptors CCR10 and CXCR4 by tumor cells correlate with cutaneous metastatic ability.

METHODS

Clinical records from Kaohsiung Medical University Hospital, Kaohsiung, Taiwan, during 20 years (1986-2006) were reviewed and cases of biopsy-proven primary internal malignancies and cutaneous metastases were identified. Immunohistochemical staining with antibodies to CCR10 and CXCR4 was performed on a selected number of internal malignancies with and without skin metastases.

RESULTS

From 12,146 patients with internal malignancies, we found 124 cases (1.02%) with cutaneous metastases. The highest rates of skin metastases were found to occur from carcinoma of the breast, followed by the lung, oral mucosa, colon and rectum, stomach, and esophagus. However, the rate of cutaneous metastasis from breast cancer was much lower compared with previous studies involving Caucasians. In general, adenocarcinomas gave rise to cutaneous metastases at a higher frequency compared with other histologic subtypes. In addition, the expressions of CCR10 and CXCR4 by tumor cells did not correlate well with the presence or absence of skin metastases.

LIMITATION

This study is retrospective in nature.

CONCLUSIONS

Different internal malignancies metastasize to the skin with different frequencies, and the rates at which different malignancies metastasize to cutaneous sites differ between the Taiwanese and Caucasian populations. The mechanisms responsible for the cutaneous metastatic ability of certain malignancies likely involve factors other than chemokine receptors CCR10 and CXCR4, because their expressions by tumor cells are neither necessary nor sufficient for the formation of skin metastases.

Bag-1 proteins in oral squamous cell carcinoma

Bag-1 is an anti-apoptotic protein that exhibits altered expression in many malignancies, including oral squamous cell carcinoma. The bag-1 gene gives rise to different protein products with different subcellular localisations through alternative translational initiation sites. In oral squamous cell carcinoma, cytoplasmic expression has been associated with metastasis to regional lymph nodes and poor prognosis. In contrast, the longest Bag-1 isoform is nuclear and may regulate differentiation in oral epithelium. In this review, the functions of the three isoforms of Bag-1 expressed in oral epithelial cells are discussed in relation to their contribution to oral carcinogenesis.

High mobility group box-1-inducible melanoma inhibitory activity is associated with nodal metastasis and lymphangiogenesis in oral squamous cell carcinoma

Melanoma inhibitory activity (MIA) is an 11-kDa secretory protein isolated from malignant melanoma cells that is correlated with invasion and metastasis in various human malignancies. We examined MIA expression in 62 oral squamous cell carcinomas (OSCC) by immunohistochemistry. MIA expression was significantly associated with nodal metastasis (P = 0.00018). MIA expression was also associated with expression of high mobility group box-1 (HMGB1) (P < 0.0001) and lymph vessel density (P < 0.0001). Expression levels of MIA, HMGB1, nuclear factor kB (NFkB) p65 and HMGB1-NFkB p65 binding were significantly higher in a metastatic human OSCC cell line (HSC3) than those in a non-metastatic OSCC cell line (HSC4). Treatment with receptor for advanced glycation end products (RAGE) antisense or small interfering RNA and human recombinant HMGB1 (hrHMGB1) did not affect MIA expression, whereas HMGB1 antisense or siRNA treatment decreased MIA expression in HSC3 cells. Then HMGB1 enhanced MIA expression as an NFkB cofactor but not as a RAGE ligand. MIA neutralization by MIA antibodies increased extracellular signal-related kinase 1/2 phosphorylation, but decreased p38 phosphorylation and the expression of vascular epithelial growth factor (VEGF)-C and -D. Treatment with p38 inihibitor decreased VEGF-C and -D expression in HSC3 cells. These results suggest that MIA expression is enhanced by the interaction of intracellular HMGB1 and NFkBp65 and MIA is closely involved in tumor progression and nodal metastasis by the increments of VEGF-C and VEGF-D in OSCC.

H-Ras mutation modulates the expression of major cell cycle regulatory proteins and disease prognosis in oral carcinoma

Activating mutations of the Ras is a moderately frequent event in oral carcinogenesis in Indian patients. Ras pathway has essential roles in regulation of various phases of the cell cycle, especially at G1 phase. Despite a large body of in vitro evidence, the multidimensional interaction between mutated Ras pathway and G1 cell cycle regulatory proteins in tumours in vivo is poorly determined. In the present study, DNA samples were screened for mutations in hot spot exons of B-Raf and hot spot codons 12, 13 and 61 of H-, K- and N-Ras by PCR-SSCP. Mutations were confirmed by direct sequencing. Expression of G1 cell cycle regulatory proteins-cyclin D1, CDK4, Rb, p53, p16 and p21 and proliferation marker PCNA was analysed immunohistochemically. The results revealed the absence of B-Raf mutations in oral carcinoma in spite of 12.5% of the samples showing H-Ras mutation. The H-Ras mutant cases showed significantly low cyclin D1 (P=0.027) and CDK4 (P=0.046) expression and overexpression of Rb (P=0.011) and p16 (P=0.026). H-Ras mutant carriers also had significantly high recurrence-free survival (P=0.033). In summary the present study demonstrated an epistatic interaction between H-Ras mutation and G1 cell cycle regulatory proteins in vivo. H-Ras mutation, thus, defines a molecular subtype of oral carcinoma with favourable outcome and unique biology.

Overexpression of galectin-1 at the tumor invasion front is associated with poor prognosis in early-stage oral squamous cell carcinoma

Metastasis is a final and eventually fatal step in the progression of oral squamous cell carcinoma (OSCC) and typically accompanies a large primary tumor. Metastasis may also present from a small primary tumor and progress rapidly; therefore, early diagnosis is important for patients with small primary tumors. Galectin-1 is one significantly upregulated tumor-associated protein in many neoplasms. To determine the clinical significance of galectin-1, we analyzed its expression in clinical samples by immunohistochemistry and reverse transcription-quantitative polymerase chain reaction assay. Galectin-1 protein was significantly overexpressed in the tumor-associated stroma as well as the invasion front during early oral carcinogenesis (P<0.05). During the metastatic stage, the only significant immunoreactivity was at the tumor invasion front (P<0.05). Although galectin-1 mRNA was not significantly upregulated in the whole cancerous tissue, it was upregulated in stromal parts during early-stage OSCC and in epithelial parts at the metastatic stage. Survival analysis and a Cox's proportional hazards model showed that synchronous upregulation of galectin-1 protein and mRNA was correlated with worse disease-free survival in early-stage OSCC (P=0.024 and P=0.047, respectively). Our findings suggest that galectin-1 upregulation at the tumor invasion front might be a predictor of early metastasis in oral carcinogenesis.

Prognostic factors associated with the survival of oral and pharyngeal carcinoma in Taiwan

Background

In Taiwan, a distinct ethnic group variation in incidence and mortality rates has been suggested for most carcinomas. Our aim is to identify the role of prognostic factors associated with the survival of oral and pharyngeal carcinoma in Taiwan.

Methods

Taiwan Cancer Registry records of 9039 subjects diagnosed with oral and pharyngeal carcinoma were analyzed. The population was divided into three ethnic groups by residence, which were Taiwanese aborigines, Hakka and Hokkien communities. Five-year survival rates were estimated by Kaplan-Meier methods. Ethnic curves differed significantly by log-rank test; therefore separate models for Taiwanese aborigines, Hakka and Hokkien were carried out. The Cox multivariate proportional hazards model was used to examine the role of prognostic factors on ethnic survival.

Results

The five-year survival rates of oral and pharyngeal carcinoma were significantly poorer for Hokkien community (53.9%) and Taiwanese aborigines community (58.1%) compared with Hakka community (60.5%). The adjusted hazard ratio of Taiwanese aborigines versus Hakka was 1.07 (95%CI, 0.86–1.33) for oral and pharyngeal carcinoma mortality, and 1.16 (95%CI, 1.01–1.33) for Hokkien versus Hakka. Males had significantly poor prognosis than females. Subjects with tongue and/or mouth carcinoma presented the worst prognosis, whereas lip carcinoma had the best prognosis. Subjects with verrucous carcinoma had better survival than squamous cell carcinoma. Prognosis was the worst in elderly subjects, and subjects who underwent surgery had the highest survival rate.

Conclusion

Our study presented that predictive variables in oral and pharyngeal carcinoma survival have been: ethnic groups, period of diagnosis, gender, diagnostic age, anatomic site, morphologic type, and therapy.

The expression of receptor for advanced glycation end products is associated with angiogenesis in human oral squamous cell carcinoma

The receptor for advanced glycation end products (RAGE) is associated with cancer progression in several human cancers. In this study, we examined the roles of RAGE in the angiogenesis of oral squamous cell carcinoma (OSCC). RAGE concentration was examined in 20 OSCC tumors by enzyme-linked immunosorbent assay (ELISA). The microvessel density (MVD) and lymph vessel density (LVD) were examined by immunostaining. Concentrations of vascular endothelial growth factor (VEGF) and VEGF-C were examined in tumor tissues by ELISA. Tumoral RAGE concentration was associated with higher tumor MVD (P = 0.0123) and tumor VEGF concentration (P = 0.0344), but not with LVD and VEGF-C concentration. Treatment with RAGE ligand, high-mobility group box (HMGB)-1 increased the secretion of VEGF but not that of VEGF-C in human OSCC cell lines, HSC-3 and HSC-4. The effect of HMGB-1 was abrogated by RAGE down-regulation by antisense S-oligodeoxynucleic acid. These results suggest that RAGE expression is closely associated to angiogenesis in OSCC.

Expression of ets-1 is not affected by N-ras or H-ras during oral oncogenesis

PURPOSE

To determine whether ras-activated cascades lead to activation of ets-1 expression in sequential histological stages of oral oncogenesis in an experimental animal model.

METHODS

Thirty-seven Syrian golden hamsters were divided into three experimental groups (A, B, C) and one control group. The hamsters' buccal pouches in experimental groups were treated with 0.5% 9, 10-dimethyl-1, 2-benzanthracene (DMBA) for 14 weeks and were excised at 10, 14, 19 weeks, respectively. The biopsies were classified pathologically (normal mucosa, hyperkeratosis, hyperplasia, dysplasia, early invasion, well and moderately differentiated carcinoma) and studied immunohistochemically. The two-tailed Student's t test was performed for each animal group and for each histological category.

RESULTS

The ets-1 expression increased in early stages of oral tumor formation and invasion. The expression of N-ras gradually decreased during oral oncogenesis, as previously observed with H-ras.

CONCLUSIONS

Neither N-ras nor H-ras affects ets-1 expression in contrast to other types of cancer in which N-ras and ets-1 are implicated in the same signalling pathway. Therefore, the existing pathway implicating these proteins might be somehow altered in oral cancer. It seems that ets-1 is a good prognostic marker for invasiveness and progression of oral cancer.