In contrast, patients carrying the E2A-PBX1 and TEL-AML1 gene fusions displayed a decreased MTX-PG accumulation associated with the diminished expression of SLC19A1 in E2A-PBX1 and the elevated expression of ABCG2 in TEL-AML1 ALL patients [184]. This evidence concerns the gene SLC19A1 and acute lymphoblastic leukemia.