José Roberto Vasconcelos de Podestá

Polymorphisms in methylenetetrahydrofolate reductase and cystathionine beta-synthase in oral cancer - a case-control study in southeastern Brazilians

INTRODUCTION Oral squamous cell carcinoma (OSCC) is a serious public health problem, due to its high mortality rate and worldwide rising incidence. OSCC susceptibility is mediated by interactions between genetic and environmental factors. Studies suggest that genetic variants encoding enzymes involved in folate metabolism may modulate OSCC risk by altering DNA synthesis/repair and methylation process. OBJECTIVE The goals of this study were to evaluate the association of three genotypic polymorphism (MTHFR C677T, MTHFR A1298C and CBS 844ins68) and oral cancer risk in southeastern Brazilians and evaluate the interactions between polymorphisms and clinical histopathological parameters. METHODS This case-control study included 101 cases and 102 controls in the state of Espírito Santo, Brazil. MTHFR genotyping was done by PCR-RFLP (polymerase chain reaction - restriction fragment length polymorphism) and CBS genotyping by PCR (polymerase chain reaction) analysis. RESULTS MTHFR C677T polymorphism was associated with lymph node involvement. Genotype CT+TT acted as a protective factor. MTHFR A1298C AC+CC genotype was associated with tumor differentiation, and possibly with a better prognosis. In risk analysis, no correlation was observed between genotypes and OSCC. CONCLUSION We concluded that MTHFR C677T, MTHFR A1298C and CBS 844ins68 polymorphisms were not associated with OSCC risk in southeastern Brazilians; however, we suggest a prognosis effect associated with MTHFR C677T and A1298C polymorphisms in OSCC.

Clinical features of oral and oropharyngeal squamous cell carcinoma HPV related.

Background The oral squamous cell carcinoma (OSCC) is a malignant neoplasm originating from the epithelial lining of the oral cavity, accounting for about 95% of malignant lesions in this region. In Brazil, the oral cavity is the fifth location of the highest incidence of cancer in men and the seventh in women. In 2012, Brazil was estimated at 9,990 new cases of oral cancer in men and 4,180 in women [1]. The oral cavity and oropharynx present in the epithelium coating a wide variety of tissue patterns occupying very close areas. Thus, the study of squamous cell carcinoma of the oral cavity and oropharynx should consider the anatomical site, size and pattern of tumor infiltration as characteristics that may influence the biological behavior of the tumor [2]. This study aimed to evaluate the clinical and pathological aspects related to human papillomavirus (HPV) in squamous cell carcinoma of oral and oropharyngeal.

Frequency of Human Papillomavirus infection in squamous cell carcinoma of the oral cavity and oropharynx

Background Squamous cell carcinoma of the oral cavity and oropharynx is a public health issue, with over 200,000 new cases worldwide each year [1]. Studies show that the incidence is higher in male individuals, aged between 40 and 55 years. The consumption of tobacco and alcohol are wellestablished risk factors for developing head and neck cancer, and studies have been shown synergism between these substances, which contributes to the increased risk [4]. Recently, persistent infection with high risk Human Papillomavirus (HPV) has been identified as a potential risk factor for the development of these tumors [2]. HPV is a DNA virus that features tropism to epithelial cells. The high risk HPV types, such as types 16 and 18 have the ability to integrate their DNA into the host cell DNA, immortalizing keratinocytes, with great possibilities of causing a cancer by infecting cells [3]. This study aims to evaluate the frequency of HPV infection, smoking and alcohol consumption related to the development of squamous cell carcinomas of the oral cavity and oropharynx.

PERFIL DE METILAÇÃO DO GENE P16 EM MUCOSA ORAL DE INDIVÍDUOS COM CARCINOMA EPIDERMOIDE DA CAVIDADE BUCAL

Oral cancer is the seventh most frequent type in our population and approximately 90% of these malignancies are squamous cell carcinoma. Genetic alterations in tumor suppressor genes increase the risk of tumor development, since these genes are associated with cycle cell control. Epigenetic changes involving cell cycle regulatory genes are related to the initiation and progression of various tumors. The hyper methylation of tumor suppressor gene p16 is found in many types of cancers and is associated with gene silencing. The aim of this study was to determine the methylation of the promoter region p16 in samples of normal oral mucosa from patients with oral squamous cell carcinoma. The technique of MS-PCR (Methylation-Specific Polymerase Chain Reaction), which allowed the distinction between methylated and non-methylated alleles in the promoter region p16, was used. This study analyzed 23 samples, and 17.4% tested positive for methylation. Among these, 50% were chronic users of tobacco and 25% alcohol. Aging may be associated with methylation of p16, since the average age of positive patients was 72 years and negative patients was 56 years. The results suggest that hyper methylation of the p16 can become important molecular marker for oral squamous cell carcinoma.