In the co-culture system, several leukemia cells were hidden in the matrix fiber layer formed by the intersection of stromal cell fibers, and the number of leukemia cells attached to TGF-β conditioned MSCs seemed to be more than that of the co-culture system of MSCs, but decreased after AMD3100 was added to the co-culture system (Figure 4D). Here, TGFB1 is linked to leukemia.