MNX1 and acute myeloid leukemia: After a period of several weeks of leukemic growth in mice, allowing initial engraftment in the orthotopic niche and later following substantial proliferation within the BM and dissemination to extramedullary sites in the blood, cells with MNX1 knockdown showed a pronounced disadvantage compared with cells with control knockdown in all organs studied (Fig. 7B), suggesting that lack of MNX1 reduced fitness of PDX AML-661 cells in vivo.