Oral Cancerization Research Articles

Topical application of green tea polyphenol (−) epigallocatechin-3-gallate for prevention of recurrent oral neoplastic lesions

A preliminary study was conducted to investigate feasibility of using an oral cancer chemopreventive agent (-)-epigallocatechin-3-gallate (EGCG), the most biologically active component in the green tea extract, in a form of 'swish-and-spit' mouthwash. Such application of EGCG is beneficial as it maximizes exposure of the oral mucosa to the agent but minimizes systemic side effect. The study was conducted on individuals suspected to have oral field cancerization who are at a high risk for developing recurrent oral precancerous and carcinomatous lesions. EGCG was used as a daily mouthwash for 7 days. EGCG's ability to modulate target molecules implicated in oral carcinogenesis was assessed by measuring the change in expression level of biomarkers. Immunohistochemical expression of phosphoactivated epidermal growth factor receptor (pEGFR), cyclooxygenase-2 (cox-2) and ki-67 were evaluated at baseline and at the endpoint (day 8). Although not statistically significant, overall decrease in expression levels of pEGFR (27.5%), cox-2 (15.9%) and ki-67 positive cells (51.8%) were observed following EGCG treatment. Moreover, a detectable level of EGCG was found in saliva but not in plasma after the one-week treatment regime, demonstrating local availability of EGCG in oral mucosa without significant systemic absorption. To best of our knowledge this is the first study to explore use of oral cancer chemopreventive agent in a form of mouthwash in patients with oral field cancerization. Although a definitive conclusion was not reached due to limited sample size, if proven effective, EGCG therapy may offer a non-invasive preventive modality for oral field cancerization.

Oral field cancerization: Figure 1:

A 76-year-old man with chronic obstructive lung disease and a 60 pack-year history of smoking presented with diffuse lesions on his tongue that had been evolving for three years ([Figure 1][1]). After multiple biopsies showing a range of dysplasia, all lesions were surgically removed. He has stopped

Oral Field Cancerization: A Review

The concept of oral field cancerization (OFC) has been ever changing since its first description by Slaughter et al in 1953. The concept of OFC explains the mechanisms by which second primary tumors (OPTs) develop- OPTs are the tumor-, which develop in the oral cavity in succession to the primary malignant tumors, which might vary in duration ranging from few months to years. The classical mechanism, which was originally observed by Slaughter describes that in the individuals with adverse habits, large areas of the aerodigestive tissue are affected by long-term exposure to carcinogens. In this preconditioned epithelium, multifocal carcinomas can develop as a result of independent mutations, and thus would not be genetically related. Although this mechanism was accepted for a quite a long time, the controversies began with the advent of new mechanism called the theory-, which explains that a single cell, on exposure to carcinogens, is transformed and give- rise to one large extended premalignant field by clonal expansion and gradual replacement of normal mucosa. In this field of various subclones, two separate tumors can develop after accumulation of additional genetic alteration-. Both tumors have the same clonal origin, and would thus share at least one early genetic event, which occurred before the initial clonal expansion. Also, the molecular studies regarding OFC have been expanding exponentially since a few years. The need for chemoprevention and the management of OFC with its resultant effect of development of second primary tumors has been challenging till today. Hence, the article tries to explain the conflicting aspects of various mechanisms by which SPTs develop, the molecular techniques, chemoprevention and therapeutic implications for oral field cancerization.

Fibroblast growth factor‐2 expression during experimental oral carcinogenesis. Its possible role in the induction of pre‐malignant fibrosis

The fibroblastic growth factor (FGF)-2 has been shown to induce angiogenesis in several tumor types. To date, the activity of FGF during the development of oral pre-cancerous lesions has not been analyzed. We herein evaluated the role of FGF-2 in the pre-cancerous and cancerous lesions in the hamster cheek pouch oral cancer model. Expression of FGF-2 and its receptors FGFR-2 and FGFR-3 was assessed by immunohistochemistry at different stages of the carcinogenesis protocol. Activity of FGF-2 isoforms was analyzed by Western blots. Increase and abnormal localization of FGF-2 expression was evident in cancerized epithelium before it was possible to detect morphologic alterations. The changes in FGF-2 are concomitant with the evolution of subepithelial fibrosis. Immunolabeling of carcinomas was faint or completely negative. Increases of FGF-2 activity are mainly due to the increase in the 18 kDa isoform. Receptors 2 and 3 of FGF are present in epithelium, fibroblasts, and vascular endothelia of control samples and in all stages of malignant transformation. Our results would suggest a role for FGF-2 in the epithelium-connective interactions and a deregulation of its expression in the early stages of oral cancerization. In pre-cancerous tissue FGF-2 would play a central role in the development of fibrosis and a more collateral role in the induction of angiogenesis. The data would indicate its involvement in the process via the 18 kDa isoform.

From the chromosome to DNA: Restriction fragment length polymorphism analysis and its clinical application

Understanding how chromosomal alterations contribute to acquired and inherited human disease requires the ability to manage the enormous physical and informational complexity of the deoxyribonucleic acid (DNA) packaged within. Important concepts and techniques involved in the analysis of DNA include restriction enzymes, Southern blotting, and restriction fragment length polymorphism/linkage analysis. These techniques have been essential in the understanding and diagnosis of several syndromes associated with the head and neck. The purpose of this article is to introduce DNA structure, describe some techniques fundamental to DNA analysis, and provide a brief overview of the clinical applications of this technology with respect to dentinogenesis imperfecta and oral field cancerization. © 2001 American Association of Oral and Maxillofacial Surgeons