 Methods We will classify the patients to rapid early responder RER and slow early responder SER, according to the treatment response after induction remission and risk factors at diagnosis. SER includes M2 5-25 or leukemic cells at bone marrow exam or M3 25 or more of leukemic cells at bone marrow exam response at the 14th day of the start of induction remission. If a patient showed total WBC count 100,000μL, had testis or CNS CNS 3 involvement at diagnosis and was diagnosed as T-ALL, the patients will also be included into the SER group. 