We used Molt-4 and CEM cells as T-ALL model cancer cells and assessed the mechanism of cell death by evaluating mitochondrial (ratio Bax-Bcl-2, ROS and TMRE) and nuclear (γ-H2Ax, cell cycle, and DNA degradation) alterations and the role of ROS and caspases in cell death mechanism. The gene discussed is BCL2; the disease is acute lymphoblastic leukemia.