To unravel the potential connections between acidic niches and LIC activities, we established an MLL-AF9–induced murine acute myeloid leukemia (AML) model in which leukemia cells only express markers for myeloid lineages (Mac-1 and Gr-1) but not for lymphoid lineages (CD3 and B220), as described previously (12). This evidence concerns the gene PTPRC and acute myeloid leukemia.