Finally, in order to further validate Cxcl1/Cxcr2 and Il6/Il6R as mechanisms by which Pml regulates leukemic cells non-cell autonomously, we employed the HoxA9–Meis1 AML model, and we performed complementary treatments: we added anti-Cxcr2 and anti-Il6 blocking antibodies to the co-cultures with Pml+/+ MSCs, while on the contrary we added the recombinant proteins Il6 and Cxcl1 to the co-cultures with Pml−/− MSCs. The gene discussed is MEIS1; the disease is acute myeloid leukemia.