IL6 and acute lymphoblastic leukemia: Cytokine array analysis using cytokine-directed antibodies (Table S3) and the NALM6 (IGH::DUX4) cell line, which is derived from ALL in relapse,35 revealed that 24 cytokines including IGFBP2, VEGF, IL6, and CXCL12 were enriched in MSC-ALL co-culture media compared to NALM6 mono-culture; conversely, no cytokines were enriched in co-culture media compared to MSC mono-culture, indicating that enriched cytokines in co-culture were secreted by MSCs (Figures 2A-2C).