In addition to tumor genetic, the individual genetic variability is important in the delivery of the most efficacious treatment plan. Germ line polymorphisms, in genes of drug-metabolizing enzymes, transporters, receptors, and drug targets, can greatly affect the individual’s response to therapy. It is estimated that germ line polymorphisms in genes involved in antileukemia drug metabolism are common, with the frequency of the variant allele ranging from 5% to 50%