Consistently, flow cytometry analysis revealed the percentage of GFP+ cells was decreased in the peripheral blood, BM, spleen, liver, and lungs of the mice treated with the sh-circAF4 RS4;11 cells compared with that in the animals treated with the sh-NC-transfected cells (Fig. 3e, and Additional file 1: Figure S2b and c), suggesting that MLL-AF4 leukemia may depend on circAF4 for its maintenance and progression. This evidence concerns the gene AFF1 and leukemia.