Many tumor suppressor genes (such asp16, Rb, VHL, E-cadherin, andhMLH1) that are silenced by mutation are also inactivated by gene silencing through DNA methylation. Characterization of genes hypermethylated in human cancers but not in normal tissues not only provides insights into cancer biology but also permits the use of methylation-specific polymerase chain reaction-based assays that could serve as diagnostic tests for the early detection and early diagnosis of this disease. To this end, research aimed at the identification and characterization of the methylation status of known and candidate tumor suppressor genes is one strategy for finding putative diagnostic markers. This chapter describes several methods of methylation analysis.
