Ed with imatinib and different concentrations of IGFBP3 blocking antibody (anti-IGFBP3) or control IgG and viability assessed with the MTS assay. Treatment with anti-IGFBP3 alone significantly reduced cell viability (p = 0.0018) relative to control IgG (Figure 4A). To determine the effects IGFBP3 neutralization on imatinib sensitivity, MTS data were analyzed with a two-way ANOVA (interaction: p