Significant correlations of methylation levels with tumor grade were found for APC, CDKN2A, EFEMP1, L1RE1, MGMT, PTEN, RARB, and RASSF1. CDKN2A and PTEN showed minimal to absent methylation, therefore, an analysis regarding tumor grade was deemed to be not meaningful (data not shown). This evidence concerns the gene APC and neoplasm.