negative regulatory molecules PTP1B and Abi-1. Their inactivation is related with progression into blast crisis. BCR/ABL pathway could also active PI64K/Akt/STAT5 pathway which has anti-apoptotic activity. BCR/ABL induce cell adhesive and migratory abnormalities because the mutation will lead an abnormal response to chemokine SDF-1 MLL gene encode Histone-lysine N-methyltransferase (HRX), which is a histone methyltransferase. It is a positive regulator for gene transcription. It has been shown that associates with Host cell factor C1, CREB binding protein, WDR5, CTBP, MEN1, etc. The rearrangement of MLL are related with different kinds of aggressive acute leukemias. Most of biphenotypic leukemia in children is due to the rearrangement of MLL Besides them, other gene abnormalities has been reported. Such as t(8;21), t(15;17), del(6q), del(12p), t(x;12) and t(14;19). In BAL patients, it is prone to bruising, spotting, which is due to megakaryocytes that could produce platelets decrease, resulting in a lack of platelets. Anemia: reduction metrocytes that could produce red blood cells, resulting in a lack of red blood cells. Patients are prone to asthma and dizziness in walking or exercise. Persistent fever, infection prolonged healing: Most of the white blood cells are leukemia cells, no normal function, leading to decreased immunity, susceptible to infection. Diagnosis Following observation of the symptoms, the patients need to get complete blood counts and a bone marrow examination. If the patient has leukemia, the morphology and immunophenotype check is needed to make sure the type of leukemia. The morphology of the blast in BAL is not certain. The cells could display both myeloid lineage and lymphoid or undifferentiated morphology. Therefore, the diagnosis cannot based on the morphology result. The immunophenotype check is the most important basis of the diagnosis of BAL. Before 2008, the diagnosis of BAL was based on a score system proposed by the European Group for the Immunological Classification of Leukemias (EGIL) which could differentiate from other kinds of acute leukemia. The table shows this method. If the score of only one lineage is higher than 2, the acute leukemia could be acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL). According to the original EGIL scoring system BAL is defined when scores are over two points for both myeloid and T- or B- lymphoid lineages. In 2008, WHO established a new and strict criteria standard for diagnosis of BAL. The presence of specific T-lymphoid antigens, cytoplasmic CD3 (cCD3), MPO and CD 19 became the