Acute lymphoblastic leukemia is a malignant process occurring in the developing or mature lymphocyte and may be classified as B-cell precursor ALL (early pre-B and pre-B), mature B-cell, or T-cell disease. The malignant process of ALL results from a multiple-step model of carcinogenesis. This process may begin with the overexpression of protooncogenes, chromosomal translocations producing fusion genes encoding active kinases, or altered transcription factors. However, for the malignant process to progress secondary mutations are required to alter normal differentiation leading to the development of leukemia . Many of the described initial events leading to the onset of ALL have been found to originate in utero, explaining the early onset of childhood ALL . In a retrospective study, 12 of 17 patients diagnosed with ALL between the ages of 18 months and 13 years were found to have their leukemia clone in their neonatal blood spot .