Moveover, it is believed that the treatment with both drugs have a higher efficiency on killing cancer cells than that with a single drug [18] which may be explained by the characteristics of SMAC and Caspase 8 (both upstream of Caspase 3), in that the improvement of fitness is mainly achieved under the treatment of both drugs (the last two columns of Table 4). The gene discussed is CASP8; the disease is cancer.