Hypermethylation at CpG islands of promoter regions of many ephrins, including EfnA5, and Eph receptors have been demonstrated in acute lymphoblastic leukaemia [48] and miRNAs, such as miR-210 and miR-26b, have been shown to downregulate the expression of EfnA1 in hepatic ischaemia [49] and EphA2 in gliomas [50]. This evidence concerns the gene EFNA1 and acute lymphoblastic leukemia.