Simultaneously, we suggested that compared with the DC-CIK cell treatment group, the viability of the cocultured leukemia cells with activated T cells was markedly decreased after treatment with MMP9- and CCL1-silenced DC-CIK cells alone or in combination, especially the MMP9 and CCL1 joint treatment group (Figure 7(a)). This evidence concerns the gene MMP9 and leukemia.