Analysis of p15, p16, MGMT, and DAPK genes methylation by MSP in representative cases of DLBCL. The presence of a visible PCR product in lanes U indicates the presence of unmethylated allels (154, 151, 93, and 106 bp, respectively), while the presence of product in lanes M indicates the presence of methylated allels (148, 150, 81, and 98 bp, respectively). NL = normal lymphocytes as a positive control for unmethylated allels; PC = in vitro methylated DNA from normal lymphocytes as a positive control for methylated allels; MW = molecular weight marker (50 bp).