Because our data have shown that AML cells transduced only with 1 CD84 silencing sequence can overcome shCD84 in vivo, to enhance the efficiency of CD84 knockdown, and to conduct longer term in vivo studies, we transfected MLL-AF9 cells with both shCD84-1 and shCD84-2 targeting CD84. This evidence concerns the gene MLLT3 and acute myeloid leukemia.