Hypermethylation Pattern of COX-2 and Rb1 in Head and Neck Squamous Cell Carcinomas

ABSTRACT

Head and neck cancer is among the ten most common human cancers worldwide, being 90% of all cases squamous cell carcinoma histological subtype. These tumors are always associated with high rates of mortality and patients with disease presenting in the same site with the same stage that under go the similar treatment, may have different oncologic outcomes. These aspects show the necessity of developing effective molecular markers that may be able to increase survival rates. Epigenetic mechanisms contribute to the carcinogenesis process, especially by the methylation of cytosines in CpG islands. The identification of aberrantly methylated DNA may help carcinogenesis understanding as well as potential clinical targets for studies in cancer. We analyzed genes RB1 and COX-2 methylation status by the quantitative, high-throughput Q-MSP assay in cell lines, 30 tumor samples and 10 normal oral cavity mucosa samples. These two genes evaluation was not informative because the incidence of hypermethylation was completely absent (RB1) or ubiquitous (COX-2), RB1, regardless of tissue type. These results suggest that the hypermethylation pattern of both RB1 and COX-2 might not be a reasonable biomarker for head and neck squamous cell carcinomas.