Expression of MRP2 and MRP3 relative to cell line MCF7/CH1000 and expression of MRP4, MRP5, and SMRP relative to cell line K562 in 71 samples of precursor B-ALL, 32 samples of T-ALL, 8 samples of healthy peripheral blood mononuclear cells (PB), 6 samples of healthy bone marrow mononuclear cells (BM), 5 samples of healthy peripheral blood CD34⁺ stem cells (SC), 6 samples of healthy peripheral blood B lymphocytes (BL), and 6 samples of healthy peripheral blood T lymphocytes (TL). Mann-Whitney test for MRP3 in T-ALL versus precursor B-ALL: P < .001. Kruskal-Wallis test for MRP4 in PB versus BM versus SC: P = .002.