In this study we understood the contribution of ZAP70 gene missense mutation (rs104893674 (C > A)) in development of both lymphoid and myeloid leukemia and verified the possibility of using the rs104893674 (C > A) variant as an indicator for predicting both ALL and AML as well as mixed lineage leukemia. The gene discussed is ZAP70; the disease is acute lymphoblastic leukemia.