Simultaneous methylation profiling of tumor suppressor genes in head and neck cancer

Head and neck cancer (HNC) is a common cancer, and its prognosis has not changed during the last decades. Detection of the disease at an early stage is crucial for successful treatment, as early diagnosis can significantly increase the survival rate. Methylation of tumor suppressor genes is an early event in cancer responsible for incorrect gene silencing. Since methylation changes are reversible, they also provide a promising target for therapy. So far, only individual genes have been analyzed for aberrant methylation in HNC. In this study, we analyzed the methylation status of 24 tumor suppressor genes simultaneously by methylation-specific multiplex ligation-dependent probe amplification in matched tumor and normal tissue samples from patients with HNC. CHFR, RARβ, DAPK1, and RASFF1 genes were the most frequently methylated genes in tumor tissue. Eight genes were not methylated in any sample. The methylation frequencies for individual genes ranged from 0% to 19%. Our results indicate that methylation of tumor suppressor genes is not high as previously reported by methylation-specific polymerase chain reaction and is confined to a smaller but significant fraction of the tumors. Whether this group represents a unique entity in the disease spectrum warrants further studies.