Role of genetic factors in the etiology of squamous cell carcinoma of the head and neck

Updates on Larynx Cancer: Risk Factors and Oncogenesis

Laryngeal cancer is a very common tumor in the upper aero-digestive tract. Understanding its biological mechanisms has garnered significant interest in recent years. The development of laryngeal squamous cell carcinoma (LSCC) follows a multistep process starting from precursor lesions in the epithelium. Various risk factors have been associated with laryngeal tumors, including smoking, alcohol consumption, opium use, as well as infections with HPV and EBV viruses, among others. Cancer development involves multiple steps, and genetic alterations play a crucial role. Tumor suppressor genes can be inactivated, and proto-oncogenes may become activated through mechanisms like deletions, point mutations, promoter methylation, and gene amplification. Epigenetic modifications, driven by miRNAs, have been proven to contribute to LSCC development. Despite advances in molecular medicine, there are still aspects of laryngeal cancer that remain poorly understood, and the underlying biological mechanisms have not been fully elucidated. In this narrative review, we examined the literature to analyze and summarize the main steps of carcinogenesis and the risk factors associated with laryngeal cancer.

Development of a Machine Learning Model to Predict Recurrence of Oral Tongue Squamous Cell Carcinoma

Despite diagnostic advancements, the development of reliable prognostic systems for assessing the risk of cancer recurrence still remains a challenge. In this study, we developed a novel framework to generate highly representative machine-learning prediction models for oral tongue squamous cell carcinoma (OTSCC) cancer recurrence. We identified cases of 5- and 10-year OTSCC recurrence from the SEER database. Four classification models were trained using the H₂O ai platform, whose performances were assessed according to their accuracy, recall, precision, and the area under the curve (AUC) of their receiver operating characteristic (ROC) curves. By evaluating Shapley additive explanation contribution plots, feature importance was studied. Of the 130,979 patients studied, 36,042 (27.5%) were female, and the mean (SD) age was 58.2 (13.7) years. The Gradient Boosting Machine model performed the best, achieving 81.8% accuracy and 97.7% precision for 5-year prediction. Moreover, 10-year predictions demonstrated 80.0% accuracy and 94.0% precision. The number of prior tumors, patient age, the site of cancer recurrence, and tumor histology were the most significant predictors. The implementation of our novel SEER framework enabled the successful identification of patients with OTSCC recurrence, with which highly accurate and sensitive prediction models were generated. Thus, we demonstrate our framework's potential for application in various cancers to build generalizable screening tools to predict tumor recurrence.

No survival benefit in never-smoker never-drinker patients with oral cavity cancer

BACKGROUND

Although strongly associated with tobacco and alcohol use, many oral cavity squamous cell carcinoma (OCSCC) cases occur in patients without exposure to either, known as "never-smoker, never-drinkers" (NSND). We aimed to compare clinical outcomes between NSND and tobacco/alcohol-exposed populations and to define demographic characteristics of NSND.

METHODS

We performed a retrospective, single-institution cohort study of 672 OCSCC patients. Cox models were used to estimate differences in overall survival (OS) and recurrence-free survival (RFS) between NSND and tobacco/alcohol-exposed patients while adjusting for confounders.

RESULTS

NSND represented 25.6% of our cohort and were older, more female, and more economically advantaged. Among NSND, oral tongue tumors dominated in younger patients, while alveolar ridge tumors dominated in elderly patients. Multivariate survival analysis revealed no differences in OS or RFS between NSND and tobacco/alcohol-exposed patients.

CONCLUSION

When adjusted for independent biologic features, clinical outcomes in OCSCC are similar between NSND and tobacco/alcohol-exposed patients.

Epidemiological, Clinical, and Genomic Profile in Head and Neck Cancer Patients and Their Families

Inherited cancer predisposition genes are described as risk factors in head and neck cancer (HNC) families. To explore the clinical and epidemiological data and their association with a family history of cancer, we recruited 74 patients and 164 relatives affected by cancer. The germline copy number alterations were evaluated in 18 patients using array comparative genomic hybridization. Two or more first-degree relatives with HNC, tobacco-associated tumor sites (lung, esophagus, and pancreas), or other related tumors (breast, colon, kidney, bladder, cervix, stomach carcinomas, and melanoma) were reported in 74 families. Ten index patients had no exposure to any known risk factors. Family members presented tumors of 19 topographies (30 head and neck, 26 breast, 21 colon). In first-degree relatives, siblings were frequently affected by cancer (n = 58, 13 had HNC). Breast cancer (n = 21), HNC (n = 19), and uterine carcinoma (n = 15) were commonly found in first-degree relatives and HNC in second-degree relatives (n = 11). Nineteen germline genomic imbalances were detected in 13 patients; three presented gains of WRD genes. The number of HNC patients, the degree of kinship, and the tumor types detected in each relative support the role of heredity in these families. Germline alterations may potentially contribute to cancer development.

Etiologia do Carcinoma Epidermóide de Hipofaringe

A carcinogênese é uma alteração do controle do crescimento celular devido a uma exposição prolongada a algum agente com potencial mutagênico. O tabagismo é um importante determinante do risco de câncer de faringe, e a associação com o etilismo aumenta ainda mais este risco. Fatores nutricionais, como na síndrome de Plummer-Vinson, em que há uma anemia ferropriva, parecem ter também importância. Como apenas uma fração dos indivíduos expostos a tabagismo e etilismo desenvolvem câncer, sugere-se que fatores específicos do hospedeiro estabeleçam suscetibilidade diferente. Assim, o sexo masculino é o mais acometido, bem como a sexta e sétima décadas. Encontrou-se um risco relativo maior com a exposição a certas substâncias. Portadores de um primeiro tumor, exposição a radioterapia prévia e aos vírus da papilomatose humana (HPV) e, menos freqüentemente, EBV, apresentam maior risco de desenvolvimento de um câncer faríngeo. Parece ainda haver uma predisposição familiar, bem como uma correlação com a ativação de oncogens e a inativação de gens supressores de tumores, como o p53.

Head and neck cancer

Head and neck cancer is the seventh most common type of cancer worldwide and comprise of a diverse group of tumours affecting the upper aerodigestive tract. Although many different histologies exist, the most common is squamous cell carcinoma. Predominant risk factors include tobacco use, alcohol abuse, and oncogenic viruses, including human papillomavirus and Epstein-Barr virus. Head and neck malignancies remain challenging to treat, requiring a multidisciplinary approach, with surgery, radiotherapy, and systemic therapy serving as key components of the treatment of locally advanced disease. Although many treatment principles overlap, treatment is generally site-specific and histology-specific. This Seminar outlines the current understanding of head and neck cancer and focuses on treatment principles, while also discussing future directions to improve the outcomes of patients with these malignancies.

The role of family history of Cancer in Oral Cavity Cancer

Objectives

Oral and oropharyngeal squamous cell carcinoma (SCC) is the 10th most common cancer in the United States (8th in males, 13th in females), with an estimated 54,010 new cases expected in 2021, and is primarily associated with smoked tobacco, heavy alcohol consumption, areca nut use and persistent high-risk human papillomavirus (HPV). Family history of cancer (FHC) and family history of head and neck cancer (FHHNC) have been reported to play an important role in the development of OSCC. We aimed to investigate the role of FHC, FHHNC and personal history of cancer in first/second degree-relatives as co-risk factors for oral cancer.

Methods

This was a retrospective study of patients diagnosed with OSCC at the Division of Oral Medicine and Dentistry at Brigham and Women’s Hospital and at the Division of Head and Neck Oncology at Dana Farber Cancer Institute. Conditional logistic regressions were performed to examine whether OSCC was associated with FHC and FHHNC of FDRs and SDRs, personal history of cancer and secondary risk factors.

Results

Overall, we did not find an association between FHC, FHHNC and OSCC risk, whereas patients with a cancer history in one of their siblings were 1.6-times more likely to present with an OSCC. When secondary risk factors were considered, patients with a history of oral leukoplakia and dysplasia had a 16-times higher risk of having an OSCC.

Conclusions

Our study confirmed that a previous history of oral leukoplakia or dysplasia was an independent risk factor for OSCC. A positive family history of cancer in one or more siblings may be an additional risk factor for OSCC.

A population-based study of the epidemiology of oral squamous cell carcinoma in the Netherlands 1989-2018, with emphasis on young adults

There has been an increasing trend in oral squamous cell carcinoma (OSCC) in patients under 45 years of age. The aim of this study was to evaluate the burden of OSCC in the Netherlands between 1989 and 2018 among young adults (age 20-34 years) when compared to adults (age 35-44 years), and to describe the burden in older groups as well, utilizing cancer registry data to characterize incidence patterns by age, sex, and risk factors. A total of 18,963 cases of OSCC were reported. The overall incidence rate, as measured by annual percentage change (APC), increased significantly from 1989 to 2010 by 1.3% per year (95% confidence interval (CI) 0.9-1.7%) but decreased thereafter by -0.9% (95% CI -2.5% to 0.7%). Annual incidence increased significantly by 2.4% (95% CI 1.1-3.8%) for patients aged 20-34 years, while it decreased for those aged 35-44 years by -0.9% (95% CI -1.7% to 0.0%). In patients older than 60 years, incidence rates increased overall (60-74 years: APC 1.8%, 95% CI 1.5-2.1%; ≥75 years: APC 1.5%, 95% CI 1.2-1.9%). Overall, 66.5% of patients were smokers and 65.3% were alcohol consumers. The marked differences in incidence within the young age subgroups warrants further investigation to elucidate any likely disparity in biological process and clinical outcomes in these populations.

Familial Aggregation of Head and Neck Cancer in Taiwan

OBJECTIVES

Head and neck cancer (HNC) incidence has been increasing worldwide. We investigated the familial aggregation of developing HNC if a first-degree relative (FDR) is affected in a large database.

METHODS

This retrospective study utilized Taiwan National Health Insurance Database to assemble a cohort of all registered beneficiaries from 1997 to 2013 and identified diagnosed HNC patients with affected FDRs.

RESULTS

Of the 55,916 individuals diagnosed with HNC, 566 (1.01%) had affected FDRs. There were 525 (0.56%) males and 41 (0.05%) females. Age of onset of HNC was found to be earlier for those with an affected FDR at the fourth decade of life compared to the general population. The adjusted relative risks (RRs) of an individual with an affected FDR to develop HNC is 2.04 (95% confidence interval [CI], 1.85-2.26): 2.07 (95% CI, 1.88-2.29) if the affected relative was male, and 1.74 (95% CI, 1.31-2.30) if the affected relative was female. The greatest risk to develop HNC is if the affected individual is a twin with adjusted RR 33.04 (95% CI, 12.89-84.69). This is followed by an affected sibling at RR (95% CI) 3.46 (1.68-7.13), offspring at RR 2.28 (95% CI, 1.94-2.69), and parent at RR 1.66 (95% CI, 1.48-1.87).

CONCLUSION

Familial tendency of HNC proves the probable contribution of genetic factors to develop cancer. In areca quid endemic region, there is a high likelihood that both environmental and genetic factors work in synergy to develop HNC.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:806-812, 2021.

Familial cancer risk in family members and spouses of patients with early-onset head and neck cancer

BACKGROUND

Reported patterns of familial aggregation of head and neck cancer (HNC) vary greatly, with many studies hampered by the limited number of subjects.

METHODS

Altogether 923 early-onset (≤40 years old) HNC probands, their first-degree relatives, spouses, and siblings' offspring were ascertained. Cumulative risk and standardized incidence ratios (SIRs) were estimated.

RESULTS

Of all early-onset HNC families, only 21 (2.3%) had familial HNC cancers at any age and less than five familial early onset HNC cancers among first-degree relatives. The cumulative risk of HNC for siblings by age 60 (0.52%) was at population level (0.33%). No increased familial risk of early-onset HNC could be discerned in family members (SIR 2.68, 95% CI 0.32-9.68 for first-degree relatives).

CONCLUSIONS

Our study indicates that the cumulative and relative familial risk of early-onset HNC is modest in the Finnish population and, at most, only a minor proportion of early-onset HNCs are due solely to inherited genetic mutations.

Prognostic Value of a Family History of Oral Tongue Squamous Cell Carcinoma: A Matched-Pair Study

OBJECTIVES/HYPOTHESIS

To analyze the prognostic value of a family cancer history for predicting survival in patients with oral tongue squamous cell carcinoma (SCC).

STUDY DESIGN

Retrospective case series.

METHODS

Each patient with a family history was paired with one patient with sporadic oral tongue SCC without a family history. The primary endpoint was disease-specific survival (DSS).

RESULTS

In total, 124 patients were enrolled as participants with a family cancer history, and the 5-year DSS rate was 51%. In the matched group, the 5-year DSS rate was 40%. The difference was significant (P = .032). In the smoking patients with a family history, the 5-year DSS rate was 43%. In the smoking patients from the matched group, the 5-year DSS rate was 17%; the difference was significant (P = .028). In nonsmoking patients with a history of cancer, the 5-year DSS rate was 51%; in nonsmoking patients in the matched group, the 5-year DSS rate was 40%; the difference was not significant (P = .141).

CONCLUSIONS

A family cancer history is associated with improved DSS in surgically treated oral tongue SCC patients.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:E605-E610, 2020.

The rising rate of nonsmokers among laryngeal carcinoma patients: Are we facing a new disease?

OBJECTIVES/HYPOTHESIS

Laryngeal squamous cell carcinoma (SCC) is strongly associated with tobacco smoking. With the rising awareness of tobacco's adverse health effects, we have witnessed a global decrease in tobacco use. Nevertheless, laryngeal SCC remains prevalent and includes a subset of patients lacking the traditional risk factors.

STUDY DESIGN

A two-center retrospective cohort.

METHODS

Medical records of patients diagnosed with laryngeal SCC between 2009 and 2016 were reviewed. Data collected included demographics, smoking status, and tumor site. Patients who have never smoked were designated as nonsmokers.

RESULTS

The study included 330 patients with laryngeal SCC, of whom 75 (22.7%) were nonsmokers; this rate was relatively similar for each of the two institutions independently (21.9% and 25%). There were 285 patients with glottic SCC and 45 with supraglottic SCC. All nonsmoking patients in this cohort had glottic SCC, representing 26.3% (75/285) of the glottic SCC cases. The rate of female patients was significantly higher among nonsmokers. Of the patients with glottic SCC, females represented 25.3% (19/75) of the nonsmokers compared with 12.4% (26/210) of the smokers (P = .008). Mean age at diagnosis was 60.2 ± 17.5 years for nonsmoking glottic SCC patients and 63.6 ± 12.4 years for smokers (P = .280). However, nonsmokers demonstrated a distinct age distribution pattern. Nonsmoking females with glottic SCC demonstrated a bimodal age distribution pattern; 73.7% (14/19) were age <40 years or >75 years at diagnosis.

CONCLUSIONS

The rate of laryngeal SCC in nonsmokers is higher than what has previously been reported, representing a growing proportion, and may suggest a shift in etiology. Knowing that laryngeal SCC in nonsmokers predominantly affects the glottis, and that females and age extremities are more vulnerable, the traditional screening paradigm should be revised.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:E108-E115, 2020.

Tongue carcinoma in young adults: a review of the literature

SUMMARY

A recent reduction in the number of smoke-related tumours has been observed thanks to the diffusion of anti-tobacco campaigns carried out in the majority of developed countries. Nevertheless, as demonstrated by recent global epidemiologic studies, squamous cell carcinoma of the mobile tongue appears to be progressively increasing in incidence, particularly among young adults and especially in females. The driving mechanism responsible for such changes is still to be precisely defined. Several genetic studies have compared the mutational pattern of tongue squamous cell carcinoma in young adults to that of more elderly patients, without identifying significant differences that may help in better characterising this subgroup of subjects. Tongue squamous cell carcinomas in young adults have been historically considered as particularly aggressive clinical entities, with a high risk of loco-regional relapse, survival rates inferior to those of the general head and neck cancer group and need for a more aggressive therapy. However, considering the most recent studies, prognostic results in this patient group are heterogeneous and it is not possible to confirm this tendency. Thus, it is not justified to embrace different therapeutic approaches according to patient age. Eventually, an additional element to consider when examining young subjects affected by tongue cancer is the possibility of genetic predisposition. Alterations affecting pathways involved in DNA repair, surveillance of genetic stability or regulation of cellular growth may determine an increased likelihood of developing head and neck cancers.

Aberrant DNA methylation of the p16, APC, MGMT, TIMP3 and CDH1 gene promoters in tumours and the surgical margins of patients with oral cavity cancer

Oral cavity cancer is a type of head and neck squamous cell carcinoma (HNSCC) and contributes to significant morbidity and mortality each year. An epigenetic pathway of transcriptional inactivation for many genes has been described in various cancers, including HNSCC. For our study, we selected genes for which silencing caused by hypermethylation can promote cancer development. In 75 primary HNSCC tumours and paired surgical margins, we investigated the methylation status of the p16, APC, MGMT, TIMP3 and CDH1 gene promoters by methylation-specific PCR after bisulphite treatment. The promoter methylation rates of p16, APC, MGMT, TIMP3 and CDH1 in tumours were 58.67%, 49.33%, 58.67%, 50.67%, and 57.33% and 50.67%, 41.33%, 37.33%, 42.67%, and 25.33% in the surgical margin, respectively. Our observations confirm the presence of epigenetic changes not only in the cancer cells, but also in the surrounding mucosa and represent a basis for further analysis to unravel these complicated issues. Appropriate cancer risk assessment based on epigenetic alterations in surgical margins may influence a patient's diagnosis and cure.

Global incidence of oral and oropharynx cancer in patients younger than 45 years versus older patients: A systematic review

Head and neck squamous cell carcinoma (HNSCC) is typically regarded as a disease of elderly people. However, increasing numbers of patients worldwide with HNSCC at younger age (defined as <45 years old) have been reported in recent years. To assess geographical variations and trends worldwide in incidence of oral and oropharyngeal cancer in young patients, a systematic review was conducted in PubMed and Google scholar databases from 1975 to June 2016. Seventy-eight studies were selected for further study. Nineteen population-based studies on incidence rate were available from 13 countries, showing a prominent increase over time except for the Netherlands. A notable rise of oral (mobile) tongue cancer among white women and oropharyngeal cancer in white men was observed. Data suggest that cancer in young patients may be a distinct clinical entity and characterised by different aetiology and pathogenesis. Additionally, the relative proportion of oral and oropharyngeal cancer in young patients to total incidence revealed a significant difference between estimates from North America (5.5%) and both Africa (17.2%) and Middle East (14.5%). It is concluded that (i) a rising trend in oral and oropharynx cancers is observed in young patients worldwide; (ii) incidence studies should properly define outcomes in age cohorts and use a consensus cut-off for young patients; (iii) more population-based studies should be performed in non-Western regions to get accurate global measures of incidence for these cancers in young subpopulations and (iv) there is an urge to identify new aetiological factors in these young patients.

Effects of potentially functional polymorphisms in suppressor of cytokine signaling 3 (SOCS3) on the risk of head and neck squamous cancer

BACKGROUND

Suppressor of cytokine signaling 3 (SOCS3) has been identified as an inhibitor of JAK/STAT pathway that plays a significant role in carcinogenesis. SOCS3 and JAK2 polymorphisms may influence the gene expression or function, contributing to the disease susceptibility; however, such effect has not been evaluated in head and neck squamous cell carcinoma (HNSCC).

METHODS

A case-control study was performed to test the associations of SOCS3 and JAK2 polymorphisms with risk of HNSCC in 576 cases and 1552 cancer-free controls from China. Seven potentially functional polymorphisms predicted by bioinformatics tools were genotyped using Infinium BeadChip platform. The association between genotypes and HNSCC risk was estimated by computing odds ratios (ORs) and 95% confidence intervals (CIs) in univariate and multivariate logistic regression models.

RESULTS

We found that rs2280148 located at 3'-untranslated region of SOCS3 was significantly associated with an increased risk of HNSCC (additive model: adjusted OR = 1.21, 95% CI = 1.03-1.43, P = 0.021). Moreover, rs8064821 located in the promoter region of SOCS3 was linked with a decreased risk of the cancer (additive model: adjusted OR = 0.83, 95% CI = 0.71-0.97, P = 0.022). Combined analysis of these variants by the number of risk alleles showed a significant locus-dosage effect on the risk of HNSCC (P_trend = 0.006).

CONCLUSIONS

We provided the first evidence that SOCS3 polymorphisms may influence the risk of HNSCC, which could be applied as novel biomarkers to identify individuals at high risk of the disease.

[Cancer of the oral cavity in three brothers of the whole blood in Mauritania]

Les facteurs de risque majeurs pour les cancers de la cavité orale sont la consommation d'alcool et le tabac mais une composante héréditaire a également été évoquée. L’observation que nous vous présentons ci-dessous a pour objectif d’illustrer cette composante parmi les autres facteurs de risque plus connus. C’est l’histoire de trois frères germains ayant présenté chacun un cancer de la cavité orale avec une évolution très rapide en moins d’une année pour chacun d’entre eux. En plus du facteur familial, les facteurs de risque retrouvés chez ces patients étaient: le tabagisme, une mauvaise hygiène bucco-dentaire, une alimentation pauvre en légumes et en fruits. Le risque familial des cancers de la cavité orale était pendant très longtemps un sujet controversé mais plusieurs études récentes ont suggérées l’existence de ce risque ce qui concorde avec notre observation chez ces trois frères. Ces études ont montré aussi que bien que la composante héréditaire pour les carcinomes des voies aéro-digestives supérieures semble probable, il est important que les membres de la famille à risque comprennent que leur vulnérabilité à ces tumeurs peut être considérablement réduite par l'arrêt du tabac, la modération de la consommation d'alcool et la consommation fréquente de fruits et légumes crus. Des études plus poussées devront être réalisées dans notre pays pour préciser la place respective de ces différents facteurs de risque pour ce cancer. En attendant, la prévention et le diagnostic précoce restent les moyens les plus appropriées pour la lutte contre ce type de cancers.

Role of human papillomavirus and tumor suppressor genes in oral cancer

The incidence of oral cancer remains high and is associated with many deaths in both Western and Asian countries. Several risk factors for the development of oral cancer are now well known, including smoking, drinking and consumption of smokeless tobacco products. Genetic predisposition to oral cancer has been found in certain cases, but its components are not yet entirely clear. In accordance with the multi-step theory of carcinogenesis, the natural history of oral cancer seems to gradually evolve through transitional precursor lesions from normal epithelium to a full-blown metastatic phenotype. A number of genomic lesions accompany this transformation and a wealth of related results has appeared in recent literature and is being summarized here. Furthermore, several key genes have been implicated, especially well-known tumor suppressors such as the cyclin-dependent kinase inhibitors, TP53 and RB1 and oncogenes such as the cyclin family, epidermal growth factor receptor and RAS. Viral infections, particularly oncogenic human papillomavirus subtypes and Epstein-Barr virus, can have a tumorigenic effect on oral epithelia and their role is discussed, along with potential therapeutic interventions. A brief explanatory theoretical model of oral carcinogenesis is provided and potential avenues for further research are highlighted.

The Anatomic Distribution of Malignant and Premalignant Glottic Lesions and Its Relations to Smoking

Objective

To describe the anatomic location and distribution of glottic dysplasia and early glottic cancer.

Study Design

Case series with chart review.

Setting

Tertiary care referral center.

Subjects and Methods

Review of 167 glottic dysplasia or carcinoma patients between 2008 and 2013. Lesions were described in terms of location and size, and a novel grid system was used to map out anatomic distribution.

Results

Seventy-eight patients with dysplasia and 89 with early glottic carcinoma were included. One hundred twenty-eight were smokers and 39 nonsmokers. The medial aspect of the vocal fold was more involved than the superior aspect, 95% versus 71%, respectively ( P < .001). The superior aspect was more involved in smokers, 77% versus 51% in nonsmokers ( P = .0016). Using a grid system, the most involved area was the midpoint of the membranous vocal fold at the transition between the superior and medial aspects. Ninety-seven percent of the lesions occupied this specific area, with no difference between smokers and nonsmokers. The vocal process mucosa was involved in 48 patients. Exclusive vocal process involvement was limited to 2 cases. All other 46 patients demonstrated extensive disease, encompassing more than half of the vocal fold’s length. Carcinomatous lesions tended to be larger relative to dysplastic lesions. Otherwise, all lesion types showed a similar pattern of distribution.

Conclusions

Premalignant and malignant glottic lesions tend to involve the medial aspect of the vocal fold and the midpoint of the membranous part in particular. In smokers, lesions tend to be larger on presentation and are more likely to involve the superior aspect.

PHF21B as a candidate tumor suppressor gene in head and neck squamous cell carcinomas

A significant association between DNA losses on 22q13.31 and head and neck squamous cell carcinomas (HNSCC) was previously reported by our group. Our data indicated that PHF21B gene, mapped on 22q13.31 and encoding a protein with function of chromatin-mediated transcriptional regulation, might be a putative tumor suppressor gene. To test this hypothesis, gene copy number was assessed in 75 HNSCC and 49 matched peripheral blood samples. PHF21B losses were detected in 43 tumors and were significantly associated with patients with familial history of cancer (P < 0.0001); i.e., 36/43 cases showed a positive family history of cancer and 22/36 had first-degree relatives with cancer (P = 0.049). In attempt to investigate other mechanisms for PHF21B loss of function, DNA sequencing was performed and no mutations were detected. We next evaluated the gene expression levels after inhibition of DNA methylation in nine HNSCC and breast carcinoma cell lines. Additionally, PHF21B expression levels were evaluated in colon cancer HCT116 cells as well as in its counterpart DKO (double knockout of DNMT1 and DNMT3B). The higher expression levels of PHF21B gene detected in DKO cells were inversely correlated with the DNA methylation. Further, DNA methylation in the specific promoter-associated CpG Island was investigated. Interestingly, gene hypermethylation was detected in 13/37 tumors: 5/13 HNSCC cases had family history of cancer in first-degree relatives and 8/13 showed both, DNA methylation and PHF21B losses in the tumor sample. One patient had PHF21B loss in the peripheral blood cells and PHF21B methylation in the tumor sample. Additionally, overexpression of PHF21B in cell lines drastically reduces clonogenic and migratory abilities. These data suggest that PHF21B is a novel tumor suppressor gene that can be inactivated by genetic and epigenetic mechanisms in the human cancer.

Unraveling the molecular genetics of head and neck cancer through genome-wide approaches

The past decade has seen an unprecedented increase in our understanding of the biology and etiology of head and neck squamous cell carcinomas (HNSCC). Genome-wide sequencing projects have identified a number of recurrently mutated genes, including unexpected alterations in the NOTCH pathway and chromatin related genes. Gene-expression profiling has identified 4 distinct genetic subtypes which show some parallels to lung squamous cell carcinoma biology. The identification of the human papilloma virus as one causative agent in a subset of oropharyngeal cancers and their association with a favorable prognosis has opened up avenues for new therapeutic strategies. The expanding knowledge of the underlying molecular abnormalities in this once very poorly understood cancer should allow for increasingly rational clinical trial design and improved patient outcomes.

Oral cavity and oropharyngeal squamous cell carcinoma in young adults: a review of the literature

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is a disease of middle-aged to elderly adults. However, an increased incidence of HNSCC in young people under 45 years of age has been reported recently. In the present review, we focused on the epidemiology and aetiology of HNSCC in adults under 45 years of age.

METHODS

We reviewed literature related to HNSCC in adult patients less than 45 years of age and discussed current treatment options and prognosis.

RESULTS

HNSCC in young adults is associated with a higher incidence rate in nonsmokers, lower female-to-male ratio, a higher percentage of oral cavity and oropharynx tumours, and fewer second primary tumours. However, aside from traditional risk factors of tobacco and alcohol exposure, the causes of these cancers in young adults remain unclear. Agents that might contribute to risk include infection with high-risk human papillomavirus subtypes as well as genetic factors or immunodeficiency status. The expected increase in incidence and mortality of the young with HNSCC may become a major public health concern if current trends persist, particularly lifestyle habits that may contribute to this disease.

CONCLUSIONS

Given the younger age and potential long-term adverse sequelae of traditional HNSCC treatments, young adults should be treated on a case-by-case basis and post-therapy quality of life must be considered in any treatment-decision making process.

Head and neck cancer: past, present and future

Head and neck cancer consists of a diverse group of cancers that ranges from cutaneous, lip, salivary glands, sinuses, oral cavity, pharynx and larynx. Each group dictates different management. In this review, the primary focus is on head and neck squamous cell carcinoma (HNSCC) arising from the mucosal lining of the oral cavity and pharynx, excluding nasopharyngeal cancer. Presently, HNSCC is the sixth most prevalent neoplasm in the world, with approximately 900,000 cases diagnosed worldwide. Prognosis has improved little in the past 30 years. In those who have survived, pain, disfigurement and physical disability from treatment have had an enormous psychosocial impact on their lives. Management of these patients remains a challenge, especially in developing countries where this disease is most common. Of all human cancers, HNSCC is the most distressing since the head and neck is the site of the most complex functional anatomy in the human body. Its areas of responsibility include breathing, the CNS, vision, hearing, balance, olfaction, taste, swallowing, voice, endocrine and cosmesis. Cancers that occur in this area impact on these important human functions. Consequently, in treating cancers of the head and neck, the effects of the treatment on the functional outcome of the patient need the most serious consideration. In assessing the success of HNSCC treatment, consideration of both the survival and functional deficits that the patient may suffer as a consequence of their treatment are of paramount importance. For this reason, the modern-day management of head and neck patients should be carried out in a multidisciplinary head and neck clinic.

[Epidemiology of laryngeal and hypopharyngeal cancer in the period 1988-2012 in the material of the Otolaryngology Clinic of the Bialystok Medical University]

Malignant tumour is the second cause of death in Poland, behind cardiovascular disease. 26% of men and 23% of women die of it. Head and neck tumours are the fifth most frequent group of malignant tumours. These are mostly squamous cell carcinomas. The carcinogenic factors of tobacco smoke play an indisputable role in the pathogenesis of these tumours.

AIM OF WORK

Analysis comprising: number of patients, sex and age, site and stage of the primary tumour (T), clinical assessment of neck lymph nodes (N). The results underwent statistical analysis.

MATERIALS AND METHODS

The study involved 1313 patients who underwent surgery in the period 1988-2012 in the Otolaryngology Clinic in Bialystok (1199 men and 114 women, aged 32-86 years).

RESULTS

In the study group the proportion of men was 91.3% and women 8.7%. Histopathological verification confirmed squamous cell carcinomas in 99%. The primary tumour was most often located in the supraglottic area of the larynx (48.0%) and its clinical stage was T3 (33.5%). T1 tumours were statistically significantly more frequently found in the glottis and T4 tumours - in the hypopharynx and in the transglottic area. Swollen lymph nodes in the neck were found in 52.4% of the patients, most often N2 (37.4%). The highest percentage of patients with lymph node reaction was found in the youngest group (76.6%) and the lowest - in the eldest group (30.0%). Swollen lymph nodes were statistically relevantly more frequent in patients with supraglottic or hypopharynx tumour.

Head and neck squamous cell carcinoma in young patients

Epidemiologic analyses have shown disproportional increases of head and neck squamous cell carcinoma (HNSCC) incidence in a younger age group (younger than 45 years old), compared to patients above 45 years old. Although this group is small (5%), it includes a significant subset of the HNSCC patient population, and is characterized by a distinct clinical and etiological phenotype. HNSCC in young patients often presents without significant exposure to alcohol and tobacco and primarily affects the oropharynx and oral cavity. Exposure to human papilloma virus (HPV) has been identified as a major contributor to the pathogenesis of oropharyngeal carcinomas, and explains part of the observed incidence variation. Specific hereditary influences, including genetic predispositions accounting for an increased mutagen sensibility and inherited syndromes like Fanconi Anemia and Bloom's syndrome, have been identified as causative factors in a subgroup of young-onset HNSCC, but their cumulative influence remains at present likely underestimated. Circumstantial evidence suggests that young-onset HNSCC patients have a clinically different phenotype compared to older patients, however, the true impact of young age on HNSCC clinical behavior will remain difficult to determine unless multi-institutional databases will be combined. The rising incidence of young-onset HNSCC mandates intensification of research endeavors into its etiology, clinical phenotype and optimal management.

A pioneering epidemiological study investigating the incidence of squamous cell carcinoma of tongue in a Portuguese population

Objective: The purpose of this study was to investigate the incidence of squamous cell carcinoma (SCC) of the anterior two thirds of the tongue in a population living in central and southern Portugal, all treated at Portuguese Institute of Oncology of Lisbon, Francisco Gentil (IPOLFG). Study Design: This study was a retrospective review of all patients who had a histopathological diagnosis of SCC of the anterior two thirds of the tongue and had been treated in the Head and Neck Surgery Unit at the IPOLFG (Lisbon, Portugal), between 1st January 2001 and 31st December 2009. The risk factors evaluated were: gender; age; alcohol consumption; tobacco use; prosthesis use and the carcinoma site. Results: Of the 424 cases analyses, 71% were men. Mean age of occurrence was in 5th decade for males and the 6th decade for females, and the border of the tongue was the most common location. Alcohol consumption and tobacco had a lower impact in women, being the most common etiological factors in the male population. No significant association was observed between patients and the use of a prosthesis. Conclusions: In spite of the consumption of aohol and tobacco starting to decline in certain parts of the world, our findings showed both factors still have a significant impact in male population. Further research should be done to determine etiological factors in females.

Key words:Squamous cell carcinoma, tongue, epidemiology, Portuguese population.

Aurora kinase inhibition overcomes cetuximab resistance in squamous cell cancer of the head and neck

Squamous cell cancer of the head and neck (SCCHN) is the sixth leading cause for cancer deaths worldwide. Despite extense knowledge of risk factors and pathogenesis about 50 percent of all patients and essentially every patient with metastatic SCCHN eventually die from this disease. We analyzed the clinical data and performed immunohistochemistry for Epidermal growth factor receptor (EGFR) and Aurora kinase A (Aurora-A) expression in 180 SCCHN patients. Patients characterized by elevated EGFR and elevated Aurora-A protein expression in tumor tissue represent a risk group with poor disease-free and overall survival (EGFR(low)Aurora-A(low) versus EGFR(high)Aurora-A(high), p = 0.024). Treating SCCHN cell lines with a pan-Aurora kinase inhibitor resulted in defective cytokinesis, polyploidy and apoptosis, which was effective irrespective of the EGFR status. Combined Aurora kinase and EGFR targeting using a monoclonal anti-EGFR antibody was more effective compared to single EGFR and Aurora kinase inhibition. Comparing pan-Aurora kinase and Aurora-A targeting hints towards a strong and clinically relevant biological effect mediated via Aurora kinase B. Taken together, our findings characterize a new poor risk group in SCCHN patients defined by elevated EGFR and Aurora-A protein expression. Our results demonstrate that combined targeting of EGFR and Aurora kinases represents a therapeutic means to activate cell cycle checkpoints and apoptosis in SCCHN.

Novel germline CDKN2A mutation associated with head and neck squamous cell carcinomas and melanomas

BACKGROUND

The ability to identify individuals at increased risk of cancer is of immediate clinical relevance. Germline mutations in the CDKN2A locus, encoding the key tumor suppressor proteins p16/INK4A and p14/ARF, are frequently present in kindreds with hereditary cutaneous melanoma but have seldom been reported in families with genetic susceptibility to head and neck squamous cell carcinomas (HNSCC).

METHODS

We report the pedigree of a patient with an unusually high incidence of HNSCC and melanomas. CDKN2A mutation analysis was performed with standard capillary sequencing and multiplex ligation-dependent probe amplification.

RESULTS

A previously unreported germline CDKN2A mutation affecting only the p16/INK4A open reading frame, c.106delG (p.Ala36ArgfsX17), was detected in the proband. This mutation causes a premature termination codon.

CONCLUSIONS

Our report emphasizes the need to consider germinal CDKN2A mutations in the differential diagnosis of familial HNSCC and the importance of awareness of these tumors in carriers of CDKN2A mutations.

Transoral laser microsurgery for laryngeal cancer: a primer and review of laser dosimetry

Transoral laser microsurgery (TLM) is an emerging technique for the management of laryngeal and other head and neck malignancies. It is increasingly being used in place of traditional open surgery because of lower morbidity and improved organ preservation. Since the surgery is performed from the inside working outward as opposed to working from the outside in, there is less damage to the supporting structures that lie external to the tumor. Coupling the laser to a micromanipulator and a microscope allows precise tissue cutting and hemostasis; thereby improving visualization and precise ablation. The basic approach and principles of performing TLM, the devices currently in use, and the associated dosimetry parameters will be discussed. The benefits of using TLM over conventional surgery, common complications and the different settings used depending on the location of the tumor will also be discussed. Although the CO₂ laser is the most versatile and the best-suited laser for TLM applications, a variety of lasers and different parameters are used in the treatment of laryngeal cancer. Improved instrumentation has lead to an increased utilization of TLM by head and neck cancer surgeons and has resulted in improved outcomes. Laser energy levels and spot size are adjusted to vary the precision of cutting and amount of hemostasis obtained.

Relationship between a family history of malignancy and the incidence of laryngeal carcinoma in the Liaoning province of China

OBJECTIVE

The purpose of this study was to determine the contribution of family history of malignancy to the incidence of laryngeal squamous cell carcinoma.

DESIGN

We performed a retrospective review of classified statistics from the detailed information of cases and matched controls.

SETTING

First Hospital of China Medical University in the Liaoning province of China, between October 2005 and November 2007.

PARTICIPANTS

A total of 288 previously untreated patients with laryngeal cancer and 296 control subjects with non-malignant diseases were analysed by use of a hospital-based case-control study.

MAIN OUTCOME MEASURES

Incidence rates and family history of malignancy.

RESULTS

Single-factor logistic regression analysis indicated that the odds ratio value of a family history of malignancy was 2.0 (95% confidence interval: 1.3-3.2). Multiple logistic regression analysis confirmed this result, with an odds ratio value of 2.3 (95% confidence interval: 1.2-4.5). There was significant association between a family history of malignancy and the development of laryngeal squamous cell carcinoma.

CONCLUSIONS

A family history of malignancy plays an important role in and is an independent risk factor for the incidence of laryngeal carcinoma.

Analysis of 724 cases of primary head and neck squamous cell carcinoma (HNSCC) with a focus on young patients and p53 immunolocalization

This study evaluated 724 primary head and neck squamous cell carcinoma (HNSCC) in young and old patients, with regard to clinical profile and immunohistochemical expression of p53 protein. Associations among age, epidemiological and clinicopathological parameters, and survival analysis were evaluated. HNSCC in young people occurred in 14.5% (median age 40.7years; male-to-female ratio 5.9:1). A statistical association was demonstrated between age and family history of cancer, and between age and anatomical site. Among older patients, a higher presence of disease was noted in posterior sites. Expression of p53 was found in 71.7% of the samples and a higher expression was noted in lesions of young patients. Survival analysis showed that the age parameter is not a reliable prognostic factor for HNSCC. Among young patients, cervical metastasis was associated with worse survival. The presence of a family history of cancer in young patients could indicate genetic susceptibility and molecular disturbances in the p53 pathway in HNSCC of young and older patients seem to be distinct.

Family history of cancer: pooled analysis in the International Head and Neck Cancer Epidemiology Consortium

Alcohol and tobacco consumption are well-recognized risk factors for head and neck cancer (HNC). Evidence suggests that genetic predisposition may also play a role. Only a few epidemiologic studies, however, have considered the relation between HNC risk and family history of HNC and other cancers. We pooled individual-level data across 12 case-control studies including 8,967 HNC cases and 13,627 controls. We obtained pooled odds ratios (OR) using fixed and random effect models and adjusting for potential confounding factors. All statistical tests were two-sided. A family history of HNC in first-degree relatives increased the risk of HNC (OR=1.7, 95% confidence interval, CI, 1.2-2.3). The risk was higher when the affected relative was a sibling (OR=2.2, 95% CI 1.6-3.1) rather than a parent (OR=1.5, 95% CI 1.1-1.8) and for more distal HNC anatomic sites (hypopharynx and larynx). The risk was also higher, or limited to, in subjects exposed to tobacco. The OR rose to 7.2 (95% CI 5.5-9.5) among subjects with family history, who were alcohol and tobacco users. A weak but significant association (OR=1.1, 95% CI 1.0-1.2) emerged for family history of other tobacco-related neoplasms, particularly with laryngeal cancer (OR=1.3, 95% CI 1.1-1.5). No association was observed for family history of nontobacco-related neoplasms and the risk of HNC (OR=1.0, 95% CI 0.9-1.1). Familial factors play a role in the etiology of HNC. In both subjects with and without family history of HNC, avoidance of tobacco and alcohol exposure may be the best way to avoid HNC.

Molecular mechanisms of head and neck cancer

Despite advances in understanding the underlying genetics, squamous cell carcinoma of the head and neck (SCCHN) remains a major health risk and one of the leading causes of mortality in the world. Current standards of treatment have significantly improved long-term survival rates of patients, but second tumors and metastases still remain the most frequent cause of high mortality in SCCHN patients. A better understanding of the underlying genetic mechanisms of SCCHN tumorigenesis will help in developing better diagnostics and, hence, better cures. In this article we will briefly outline the current state of diagnostics and treatment and our understanding of the molecular causes of SCCHN.

Chromosomal radiosensitivity in head and neck cancer patients: evidence for genetic predisposition?

The association between chromosomal radiosensitivity and genetic predisposition to head and neck cancer was investigated in this study. In all, 101 head and neck cancer patients and 75 healthy control individuals were included in the study. The G(2) assay was used to measure chromosomal radiosensitivity. The results demonstrated that head and neck cancer patients had a statistically higher number of radiation-induced chromatid breaks than controls, with mean values of 1.23 and 1.10 breaks per cell, respectively (P<0.001). Using the 90th percentile of the G(2) scores of the healthy individuals as a cutoff value for chromosomal radiosensitivity, 26% of the cancer patients were radiosensitive compared with 9% of the healthy controls (P=0.008). The mean number of radiation-induced chromatid breaks and the proportion of radiosensitive individuals were highest for oral cavity cancer patients (1.26 breaks per cell, 38%) and pharynx cancer patients (1.27 breaks per cell, 35%). The difference between patients and controls was most pronounced in the lower age group (<or=50 years, 1.32 breaks per cell, 38%) and in the non- and light smoking patient group (<or=10 pack-years, 1.28 breaks per cell, 46%). In conclusion, enhanced chromosomal radiosensitivity is a marker of genetic predisposition to head and neck cancer, and the genetic contribution is highest for oral cavity and pharynx cancer patients and for early onset and non- and light smoking patients.

Genetic and environmental factors in head and neck cancer genesis

Head and neck squamous cell carcinoma (HNSCC) include squamous cell carcinomas of the oral cavity, pharynx, and larynx. Epidemiologic data suggest that the etiology and pathogenesis of HNSCC are influenced by environmental and lifestyle-related factors, such as tobacco use, ethanol consumption, papilloma virus infection, dietary factors and exposure to toxic substances. DNA repair systems and carcinogen-metabolizing enzymes can increase the risk for HNSCC but no definite causal mechanism has been demonstrated. There are several well-characterized entities that are associated with risk and prognosis of head and neck cancer, including Lynch-II syndrome, Bloom syndrome, Fanconi's anemia, xeroderma pigmentosum, ataxia telangiectasia, and Li-Fraumeni syndrome. This review aims to present the current status in our understanding of HNSCC and highlight controversies relating to the role of several factors in the genesis of the cancer.

Family history and the risk of oral and pharyngeal cancer

Scanty data are available on familial risk in oral and pharyngeal cancer. The relationship between oral and pharyngeal cancer and family history of cancer in first-degree relatives was investigated using data from a multicentric case-control study conducted in Italy and Switzerland between 1992 and 2005 on 956 cases aged less than 79 years, with histologically confirmed incident oral and pharyngeal cancer, and 2362 controls admitted to hospital for acute, nonneoplastic conditions. Logistic regression models conditioned on sex, age, study centre, and including terms for education, tobacco smoking, alcohol drinking, and number of siblings were used to estimate the odds ratios (OR) of oral and pharyngeal cancer. The multivariate ORs were similar for a family history of oral and pharyngeal cancer (2.6, 95% confidence interval, CI, 1.5-4.5) and laryngeal cancer (3.8, 95% CI, 2.0-7.2). The OR was 3.1 (95% CI, 2.0-4.8) for oral and pharyngeal cancer and laryngeal cancer combined. The OR was 7.1 (95% CI, 1.3-37.2) for subjects with 2 or more first-degree relatives with oral and pharyngeal/laryngeal cancers. Significant increases in risk were also observed for a family history of melanoma (OR = 5.8; 95% CI, 1.3-26.4) and lung cancer (OR = 1.4; 95% CI, 1.0-2.0). Compared to subjects without family history, nonsmokers, and non or moderate drinkers, the OR was 42.6 for current smokers, heavy drinkers with family history. History of oral and pharyngeal cancer and laryngeal cancer is a strong determinant of oral and pharyngeal cancer risk, independent from tobacco and alcohol.

Current topics in the epidemiology of oral cavity and oropharyngeal cancers

Oral cancer incidence rates rose dramatically during the twentieth century in the United States and Europe, especially among individuals under the age of 60 years. Although influenced by age, sex, and country of origin, incidence trends were most strongly affected by elevated risk among individuals born after approximately 1915. This cohort effect was indicative of strong behavioral influences on oral cancer risk. In this article, associations between oral cancer risk and established behavioral risk factors including alcohol and tobacco use are reviewed. Additionally, possible associations between oral cancer risk and oral hygiene, diet, nutritional status, and sexual behavior as well as the influence of genetic factors on oral cancer risk are considered. Special emphasis is placed on evaluating possible risk differences in individuals above and below the age of 45 and in users and nonusers of alcohol and tobacco.

Epidemiology of carcinogen metabolism genes and risk of squamous cell carcinoma of the head and neck

The risk association between tobacco and alcohol use with squamous cell carcinoma of the head and neck (SCCHN) is well recognized. However, clearly not all individuals who smoke or drink develop SCCHN. Individual genetic susceptibility differences in carcinogen-metabolizing enzyme function, mutagen sensitivity, apoptosis, and chromosomal aberrations either alone or in combination have been theorized to modify the risk of SCCHN. Nearly all carcinogens and procarcinogens require activation by metabolizing enzymes. Similarly, detoxifying enzymes exist and deactivate carcinogens as well as their intermediate by-products. Together these enzymes are termed xenobiotic-metabolizing enzymes; genetic polymorphisms of these enzymes can modify an individual's response to carcinogens and hence the carcinogenic potential of such exposures. In this review, we explore the available evidence in recent literature regarding the risk association between SCCHN and various xenobiotic-metabolizing enzymes, including cytochrome P450s, glutathione S-transferases, N-acetyltransferases, NAD(P)H:quinone oxidoreductase 1, alcohol dehydrogenase, and aldehyde dehydrogenase.

[The role of exogenous and epidemiological factors in etiology of squamous cell carcinoma of the head and neck in young adults]

Squamous cell carcinoma of the head and neck (HNSCC) is the malignant tumor arising most frequently in non-keratinized epithelial tissue of the upper part of the respiratory or gastrointestinal tracts. These tumors develop most commonly in the sixth or seventh decade of life and significantly less frequently in patients younger than 45 years defined as young adults. In literature, there are still many controversies concerning the origin of these tumors in this group of patients.

AIM

To estimate the role of exogenous and epidemiological factors in etiology of HNSCC in young adults.

MATERIAL AND METHODS

The study group consisted of 95 young adults (< or =< 45 years) with HNSCC and the control group of 95 older patients (> 45 years) with HNSCC, who were treated in the Department of Otolaryngology and Laryngological Oncology of Karol Marcinkowski University of Medical Sciences in Poznan during the period 2000-2004. The analysis was based on etiological questionnaires and the medical records of patients.

RESULTS AND CONCLUSIONS

1. A significant role of typical exogenous factors (active and passive exposure to tobacco smoke and alcohol abuse) was established in the etiology of HNSCC in young adults. 2. Daily active exposure to tobacco smoke in young adults is nearly the same as in older patients, but daily passive exposure is higher than in older patients. 3. Significantly higher alcohol consumption in young adults than in older patients, found in this study, may be one of the reasons of HNSCC onset in young age. 4. Occupational exposure to the HNSCC causative factors in young adults is not higher than in older patients. 5. A frequency of familial cancer in young adults with HNSCC seems to be higher than in older patients, but further observations are needed.

Chemoprevention of squamous cell carcinoma of the head and neck

PURPOSE OF REVIEW

The aim of this article is to summarize progress in understanding of the biology of squamous cell carcinoma of the head and neck and of trials to prevent malignant conversion of oral premalignant lesions and the development of second primary tumors in those already treated for squamous cell carcinoma of the head and neck.

RECENT FINDINGS

The understanding of squamous cell carcinoma of the head and neck biology is rapidly evolving. Clinical trials for chemoprevention are involving more diverse regimens, following disappointing results of retinoid monotherapy. In-vitro and animal studies form the rationale for the next generation of studies, employing combination, synergistic treatments.

SUMMARY

Based on trial data to date, no recommendation for intervention with a chemopreventive agent can be made. It is clear, however, that smoking cessation is an effective intervention for preventing oral premalignant lesions and second primary tumors. Promising trials are being conducted and designed currently. The future of this area of study will involve rational choice of multidrug regimens based on current understanding of the biology of squamous cell carcinoma of the head and neck.

Non-smoking and non-drinking patients with head and neck squamous cell carcinoma: a distinct population

OBJECTIVE

To recognize specific clinicopathological characteristics of non-smoking and non-drinking (NSND) head and neck squamous cell carcinoma (HNSCC) patients. This can increase our knowledge regarding a potentially different carcinogenesis in these patients.

STUDY DESIGN/METHODS

Retrospective analysis of data for 195 NSND patients with HNSCC and comparison with data for patients with HNSCC obtained from the Netherlands Cancer Registry.

RESULTS

Compared with all HNSCC patients in the Netherlands, our NSND patients with HNSCC were typically female (n = 142; 73%vs 26%), old at disease presentation (mean 73 years vs 64 years), and had tumors mainly of the oral cavity (n = 130; 66%vs 25%). Most tumors were stage I (n = 67; 34%) and stage IVA (n = 59; 30%). The incidence of second primary tumors (SPTs) was high (n = 32; 16%), mainly occurring in the oral cavity (n = 26; 13%).

DISCUSSION/CONCLUSION

Our study confirms that NSND HNSCC patients have different clinicopathological characteristics from those of the overall HNSCC population; however, the frequency of SPTs is as high in NSND patients as in patients who smoke and drink alcohol. More research, and particularly molecular data are needed to obtain a better understanding of head and neck cancer in NSND patients.

Advances in the biology of oral cancer

The incidence of oral cancer remains high and is associated with many deaths in both Western and Asian countries. Several risk factors for the development of oral cancer are now well known, including smoking, drinking and consumption of smokeless tobacco products. Genetic predisposition to oral cancer has been found in certain cases but its components are not yet entirely clear. In accordance with the multi-step theory of carcinogenesis, the natural history of oral cancer seems to gradually evolve through transitional precursor lesions from normal epithelium to a full-blown metastatic phenotype. A number of genomic lesions accompany this transformation and a wealth of related results has appeared in recent literature and is being summarized here. Furthermore, several key genes have been implicated, especially well-known tumor suppressors like the cyclin-dependent kinase inhibitors, TP53 and RB1 and oncogenes like the cyclin family, EGFR and ras. Viral infections, particularly with oncogenic HPV subtypes and EBV, can have a tumorigenic effect on oral epithelia and their role is discussed, along with potential therapeutic interventions. A brief explanatory theoretical model of oral carcinogenesis is provided and potential avenues for further research are highlighted.