Next, the qRT-PCR and IHC results also proved that the levels of PD-1, TIM3, LAG3, and CTLA4 were signally reduced in the AML model mice compared to the control mice, while this reduction could also be dramatically reserved by DC-CIK cells in the AML model mice; our results also testified that the elevations of PD-1, TIM3, LAG3, and CTLA4 expressions mediated by DC-CIK cells could be further strengthened by MMP9 or/and CCL1 knockdown in DC-CIK cells, in particular the cotransfection of MMP9 and CCL1 shRNAs in DC-CIK cells (Figures 9(d) and 9(e)). This evidence concerns the gene MMP9 and acute myeloid leukemia.