Methylation characteristics of 15 Eph/ephrin family genes in normal controls, ALL patients, and leukemia cell lines. (A) Bisulfite pyrosequencing was performed to determine methylation density. N represents the number of cases in each group. Methylation (%) indicates methylation density levels. Each symbol represents a data point. (B) Survival analysis of patients with ALL based on number of methylated genes. Patients were grouped in 3 different sets: methylation of 1 to 3 genes, 4 to 7 genes, and 8 to 10 genes.