Increased number of proliferating cells in oral epithelium from smokers and ex-smokers

Liquid Biopsy as a Tool for the Characterisation and Early Detection of the Field Cancerization Effect in Patients with Oral Cavity Carcinoma

Oral squamous cell carcinoma (OSCC) constitutes approximately 25% of all head and neck cancer, for which the consumption of tobacco and alcohol are the main associated risk factors. The field cancerization effect of OSCC is one of the main reasons for the poor survival rates associated with this disease. Despite some advances, its ccharacterization and early diagnosis continue to challenge modern oncology, and the goal of improving the prognosis remains to be achieved. Among new early diagnostic tools for OSCC that have been proposed, liquid biopsy appears to be an ideal candidate, as studies have shown that the analysis of blood and saliva provides promising data for the early detection of relapses or second tumours.

Promotion of cell proliferation by the proto-oncogene DEK enhances oral squamous cell carcinogenesis through field cancerization

Oral squamous cell carcinoma (OSCC) develops through a multistep carcinogenic process involving field cancerization. The DEK gene is a proto-oncogene with functions in genetic and epigenetic modifications, and has oncogenic functions, including cellular proliferation, differentiation, and senescence. DEK overexpression is associated with malignancies; however, the functional roles of DEK overexpression are unclear. We demonstrated that DEK-expressing cells were significantly increased in human dysplasia/carcinoma in situ and OSCC. Furthermore, we generated ubiquitous and squamous cell-specific doxycycline (DOX)-inducible Dek mice (iDek and iDek-e mice respectively). Both DOX+ iDek and iDek-e mice did not show differences in the oral mucosa compared with DOX- mice. In the environment exposed to carcinogen, DOX-treated (DOX+) iDek mice showed field cancerization and OSCC development. Microarray analysis revealed that DEK overexpression was mediated by the upregulation of DNA replication- and cell cycle-related genes, particularly those related to the G1 /S transition. Tongue tumors overexpressing DEK showed increased proliferating cell nuclear antigen and elongator complex protein 3 expression. Our data suggest that DEK overexpression enhanced carcinogenesis, including field cancerization, in OSCC by stimulating the G1 /S phase transition and promoting DNA replication, providing important insights into the potential applications of DEK as a target in the treatment and prevention of OSCC.

Laryngotracheal Stenosis: Risk Factors for Tracheostomy Dependence and Dilation Interval

Objective Laryngotracheal stenosis (LTS) is a fibrotic process that narrows the upper airway and has a significant impact on breathing and phonation. Iatrogenic injury from endotracheal and/or tracheostomy tubes is the most common etiology. This study investigates differences in LTS etiologies as they relate to tracheostomy dependence and dilation interval. Study Design Case series with chart review. Setting Single-center tertiary care facility. Subjects and Methods Review of adult patients with LTS was performed between 2004 and 2015. The association of patient demographics, comorbidities, disease etiology, and treatment modalities with patient outcomes was assessed. Multiple logistic regression analysis and Kaplan-Meier analysis were performed to determine factors associated with tracheostomy dependence and time to second procedure, respectively. Results A total of 262 patients met inclusion criteria. Iatrogenic patients presented with greater stenosis ( P = .023), greater length of stenosis ( P = .004), and stenosis farther from the vocal folds ( P < .001) as compared with other etiologies. Iatrogenic patients were more likely to be African American, use tobacco, and have obstructive sleep apnea, type II diabetes, hypertension, chronic obstructive pulmonary disease, or a history of stroke. Iatrogenic LTS (odds ratio [OR] = 3.1, 95% confidence interval [95% CI] = 1.2-8.2), Cotton-Myer grade 3-4 (OR = 2.6, 95% CI = 1.1-6.4), and lack of intraoperative steroids (OR = 2.9, 95% CI = 1.2-6.9) were associated with tracheostomy dependence. Nonsmokers, patients without tracheostomy, and idiopathic LTS patients had a significantly longer time to second dilation procedure. Conclusion Iatrogenic LTS presents with a greater disease burden and higher risk of tracheostomy dependence when compared with other etiologies of LTS. Comorbid conditions promoting microvascular injury-including smoking, COPD, and diabetes-were prevalent in the iatrogenic cohort. Changes in hospital practice patterns to promote earlier tracheostomy in high-risk patients could reduce the incidence of LTS.

Oral field cancerization: an update on current concepts

There always exists a field with genetically altered cells with a high risk of developing premalignant and malignant lesions. It may often happen that an individual stem cell is genetically altered and can cause the formation of a clone or a patch which is likely to turn into a tumor. This explains the higher recurrence rates following tumor resections. It is essential to identify and to treat this field in order to have greater chances to prevent cancer and achieve a better outcome. This article reports concepts, theories and markers for the assessment of field cancerization.

Targeting the epidermal growth factor receptor for head and neck cancer chemoprevention

The epidermal growth factor receptor (EGFR) has been implicated in head and neck squamous cell carcinoma (HNSCC) carcinogenesis. It is currently the only molecular target in head and neck cancers for which there are pharmacologic therapeutic interventions approved by regulatory agencies worldwide to treat advanced disease. Oral pre-malignant lesions have increased EGFR protein expression and increased egfr gene copy number compared to normal mucosa. Oral pre-malignant lesions with overexpression of EGFR or egfr gene copy number gain are at higher risk for malignant transformation. Inhibition of EGFR in pre-clinical models of oral pre-malignancies validates this approach as an effective way to reduce the incidence of oral cancer, and supports investigation of this strategy in the clinic. Clinical trials with EGFR targeted agents, including cetuximab, erlotinib, and vandetanib, are currently under way, some with promising preliminary results. If ultimately shown to reduce the risk of oral cancer, chemoprevention with EGFR inhibitors may significantly reduce morbidity and possibly mortality from HNSCC.

Oral field cancerization: current evidence and future perspectives

INTRODUCTION

Oral field cancerization implies that oral cancer does not arise as an isolated cellular phenomenon but rather as an anaplastic tendency involving many cells at once and results in the multifocal development of cancer at various rates within the entire field in response to a carcinogen especially tobacco. This concept has been frequently used to explain the occurrence of multiple primary cancers and recurrences following complete excision of oral cancer.

DISCUSSION

This review deals in detail with the origin, principle, various theories used to explain this effect and molecular, genetic, as well as cytogenetic findings related to oral field cancerization. Further, the clinical implications and future research directives are also discussed.

Characterization of a three-dimensional mucosal equivalent: similarities and differences with native oral mucosa

The aim of this study was to create and characterize a tissue-engineered mucosal equivalent (TEM) that closely resembles native mucosa. TEM consists of human primary keratinocytes and fibroblasts isolated from biopsies taken from healthy donors and seeded onto a de-epidermized dermis and cultured for 14 days at the air/liquid interface. The structure of TEM was examined and compared with native nonkeratinizing oral mucosa (NNOM). The various components of the newly formed epidermal layer, basement membrane and underlying connective tissue were analyzed using immunohistochemistry. The mucosal substitute presented in this study showed a mature stratified squamous epithelium that was similar to that of native oral mucosa, as demonstrated by K19, desmoglein-3 and involucrin staining. In addition, the expression of basement membrane components collagen type IV, laminin-5 and integrin α6 and β4 in TEM proved to be consistent with native oral mucosa. The expression of PAS, Ki67, K10 and K13, however, appeared to be different in TEM compared to NNOM. Nevertheless, the similarities with native oral mucosa makes TEM a promising tool for studying the biology of mucosal pathologies such as oral mucositis or fibrosis as well as the development of new therapies.

Effects of tobacco smoke on gene expression and cellular pathways in a cellular model of oral leukoplakia

In addition to being causally linked to the formation of multiple tumor types, tobacco use has been associated with decreased efficacy of anticancer treatment and reduced survival time. A detailed understanding of the cellular mechanisms that are affected by tobacco smoke (TS) should facilitate the development of improved preventive and therapeutic strategies. We have investigated the effects of a TS extract on the transcriptome of MSK-Leuk1 cells, a cellular model of oral leukoplakia. Using Affymetrix HGU133 Plus 2 arrays, 411 differentially expressed probe sets were identified. The observed transcriptome changes were grouped according to functional information and translated into molecular interaction network maps and signaling pathways. Pathways related to cellular proliferation, inflammation, apoptosis, and tissue injury seemed to be perturbed. Analysis of networks connecting the affected genes identified specific modulated molecular interactions, hubs, and key transcription regulators. Thus, TS was found to induce several epidermal growth factor receptor (EGFR) ligands forming an EGFR-centered molecular interaction network, as well as several aryl hydrocarbon receptor-dependent genes, including the xenobiotic metabolizing enzymes CYP1A1 and CYP1B1. Notably, the latter findings in vitro are consistent with our parallel finding that CYP1A1 and CYP1B1 levels were increased in oral mucosa of smokers. Collectively, these results offer insights into the mechanisms underlying the procarcinogenic effects of TS and raise the possibility that inhibitors of EGFR or aryl hydrocarbon receptor signaling will prevent or delay the development of TS-related tumors. Moreover, the inductive effects of TS on xenobiotic metabolizing enzymes may help explain the reduced efficacy of chemotherapy, and suggest targets for chemopreventive agents in smokers.

Effects of active non-smoking programmes on smoking behaviour in oral precancer patients

Smoking is the commonest risk factor for oral cancer and precancer. The objective of this study was to characterize smoking behaviour and attitude in a cohort of oral precancer patients in Newcastle upon Tyne, UK, and to determine changes in behaviour during diagnosis, treatment and follow-up. Twenty-seven consecutive, smoking patients with dysplastic oral lesions were recruited to the study and a detailed smoking history obtained, quantifying types and numbers of cigarettes smoked, length of smoking history, and changes in smoking behaviour during treatment episodes and long-term follow-up. All patients underwent an interventional management protocol comprising risk-factor education, histopathological diagnosis by incisional biopsy and laser excision of lesions. Patients were followed up for 5 years. Whilst there was a significant decrease in the number of cigarettes smoked at patients' most recent follow-up compared with initial presentation (p<0.001), 74% continued to smoke. Patients received advice from a smoking cessation adviser on support available to them from the local NHS (National Health Service) Stop Smoking services. Six out of 10 patients who set a 'quit date' and attended a programme had quit at the 4-week follow-up but only 5 remained non-smokers. Smoking remains a considerable problem in oral precancer patients even after interventional treatment, with the risk of further precancerous lesions and malignant transformation.

Cell proliferation and p53 expression in pseudoepitheliomatous hyperplasia of oral paracoccidioidomycosis

Paracoccidioidomycosis (PCMycosis) is a systemic mycosis frequently found in many regions of Latin America. Microscopically, it is characterised by granulomatous inflammation and pseudoepitheliomatous hyperplasia (PEH). This work describes the proliferation index and p53 expression by immunohistochemistry in PEH of PCMycosis, normal oral mucosa (NOM) and mild oral epithelial dysplasia (ED). Ki67 positive cells were present in the basal and parabasal layers in NOM and PEH, while in ED it was also observed in the spinous layer. Percentage of ki67 positive cells was 7.7, 28.2 and 46.0 in NOM, PEH and ED respectively. p53 was negative in NOM and in PEH it was expressed by few cells in the basal layer of only three cases. However, it was expressed in all cases of ED, in basal and parabasal layers. Although histologically PEH mimics well-differentiated squamous cell carcinoma, its proliferative pattern and p53 expression are more similar to NOM than to dysplasia. These findings, confirm PEH as a reactive process probably associated with the underlying chronic inflammation.

Effects of individual characteristics on healthy oral mucosa autofluorescence spectra

Autofluorescence spectroscopy is a tool for detecting tissue alterations in vivo. In a previous study, we found spectral differences between clinically normal mucosa of different patient groups. These are possibly caused by associated patient characteristics. In the present study, we explore the influences of volunteer characteristics on healthy oral mucosa autofluorescence. Autofluorescence spectra were recorded in 96 volunteers with no clinically observable oral lesions. We applied principal components analysis to extract the relevant information. We used multivariate linear regression techniques to estimate the effect of volunteer characteristics on principal component scores. Statistically significant differences were found for all factors but age. Skin color strongly affected autofluorescence intensity. Gender differences were found in blood absorption. Alcohol consumption was associated with porphyrin-like peaks. However, all differences but those associated with skin color were of the same order of magnitude as standard deviations within categories. The effects of volunteer characteristics on autofluorescence spectra of the oral mucosa are measurable. Only the effects of skin color were large. Therefore, in lesion classification, skin color should be taken into account.

Second head and neck cancers and tobacco usage

OBJECTIVES

To examine the relative incidence of second primary carcinomas in patients who continued smoking compared with those who had ceased smoking.

METHODS

This is a retrospective study based on review of the Wake Forest University-Baptist Medical Center Tumor Registry for the years 1985 through 2000. Ninety-one patients who had had an index head and neck tumor and who developed a second independent head and neck primary tumor, were identified. These cases were grouped into synchronous (different sites within 6 months) and metachronous (different site after 6 months or same site after 3 years) second tumors and were examined with respect to smoking history-specifically whether smoking had continued or ceased after the diagnosis of the index tumor.

RESULTS

Of the 91 patients identified with double head and neck tumors, 88 were tobacco users. Comprising the group of 54 patients with metachronous second primaries were 51 smokers-25 who had continued and 26 who had ceased tobacco use. Of the 26 patients who had quit smoking but had developed a second primary, 13 had stopped smoking even before the index primary had been diagnosed. The remaining 13 had stopped when the index primary was treated.

CONCLUSIONS

A review of 91 patients with double head and neck primary tumors indicate no difference in the frequency of second tumors developing in a group of patients who continued to smoke after diagnosis of their index cancers relative to patients who stopped smoking. This finding suggests a critical cellular level of cumulative and persistent damage. Methods to reverse this genetic alteration are hypothesized to be potentially more significant than smoking cessation efforts in preventing subsequent head and neck cancers.

Field change and oral cancer: new evidence for widespread carcinogenesis?

Patients with oral squamous cell carcinoma (OSCC) are at risk of developing second or multiple primary cancers as a result of field cancerization in the upper aerodigestive tract. In order to quantify the incidence of field change observable in oral mucosa, 26 consecutive new (untreated) patients presenting with a unilateral OSCC (18) or a premaligant lesion (eight) underwent 'mirror image' biopsies from clinically normal-looking mucosa at corresponding anatomical sites. A total of 15 patients (58%) demonstrated histologically abnormal tissue upon microscopic examination: six showed reactive change/cellular atypia associated with chronic irritation, seven exhibited frank dysplasia, whilst two displayed carcinoma-in-situ (CIS) or microinvasive SCC. Although not statistically significant, there was an observable trend for the lateral/ventral tongue and floor of mouth to display increased vulnerability to dysplastic change.

Long-term impact of smoking on lung epithelial proliferation in current and former smokers

BACKGROUND

Lung cancer risk remains elevated for many years after quitting smoking. To assess using proliferation indices in bronchial tissues as an intermediate endpoint biomarker in lung cancer chemoprevention trials, we determined the relationship between the extent, intensity, and cessation of tobacco smoking and proliferative changes in bronchial epithelial biopsy specimens.

METHODS

Bronchial biopsy specimens were obtained from up to six epithelial sites in 120 current smokers (median pack-years, 42) and 207 former smokers (median pack-years, 40; median quit-years, 8.1). Sections from the paraffin-embedded specimens were stained with hematoxylin--eosin to determine the metaplasia index and with an antibody to Ki-67 to determine the proliferative (labeling) index for the basal and parabasal (Ki-67 PLI) layers. All statistical tests were two-sided.

RESULTS

Biopsy sites with metaplasia had statistically significantly higher Ki-67-labeling indices than those without metaplasia (P<.001) in both current and former smokers. Increased proliferation was observed in multiple biopsy sites, with the average Ki-67 PLI of the subject strongly correlating with the metaplasia index (r =.72 for current smokers; P<.001), even in sites without metaplasia (r =.23 for current smokers; P<.001). In current smokers, the Ki-67 PLI was associated with the number of packs smoked/day (P =.02) but not with smoking years or pack-years. In subjects who had quit smoking, the Ki-67 PLI dropped statistically significantly within 1 year (P =.008) but remained detectable for more than 20 years, even in the absence of squamous metaplasia.

CONCLUSION

Smoking appears to elicit a dose-related proliferative response in the bronchial epithelia of active smokers. Although the proliferative response decreased gradually in former smokers, a subset of individuals had detectable proliferation for many years and may benefit from targeted chemoprevention. Bronchial epithelial proliferation, measured by Ki-67, may provide a useful biomarker in the assessment of lung cancer risk and in the response to chemopreventive interventions.

Evaluation of the nucleolar organizer region associated proteins in exfoliative cytology of normal buccal mucosa. Effect of smoking

An evaluation of cellular alterations in the smoker's oral mucosal cells was performed. The Exfoliative Cytology technique was applied and the cytological smears stained with silver for the enumeration of Argyrophilic nucleolar organizer regions (AgNORs). Cytological smears were collected from two anatomic sites: floor of the mouth and tongue border, in both groups, smokers and non smokers, with a purpose of correlating the smoking habit to possible cellular alterations. The enumeration of the AgNORs showed that the average number of AgNORs is higher in smokers. There is a significant difference (P=0.0001) between smears from the floor of the mouth and from tongue border in the smoking group. In this study, no correlation between number of cigarettes, age and gender was found, but the results suggest that there might be a correlation between the smoking habit and an increased rate of cellular proliferation in the oral mucosal cells.