IGF1 and medulloblastoma: However, the low baseline phosphorylation/activity of the IGF1R in BON1 and H727 cells might not have been sufficient to show the effects of specific IGF1R inhibition by NVP-AEW541; moreover, another group stimulated their cells with IGF1 to demonstrate the dependence of GSK3 phosphorylation on IGF1R activity in medulloblastoma cells [49],.