Examples of ABL1 methylation. The top panel is a representative composite Southern blot of 17 cases of CML restricted either with EcoRI alone (E) or EcoRI and Not I (EN). The band at 6.2 kb (arrow) in the EN lanes represents alleles methylated at the ABL1 Pa promoter. This methylation was quantitated by densitometric analysis of the 6.2-kb band relative to the density of all the bands in each lane. The relative methylation is indicated below each lane and ranges from 0% to 62% in these samples. The bottom panel shows examples of ABL1 methylation analysis of 8 cases of AML. None of these (and other) cases have the 6.2-kb band indicative of methylation of this CpG island.