RAC1 and osteosarcoma: ,23 Using network analyses of three published proteomic databases of integrin-associated complexes,17,34,35 we identified a putative link between IQGAP1, β1 integrin and Rac1 regulation (Fig. 2A) and demonstrated that, in fibroblast and osteosarcoma cells, suppression of IQGAP1 gene expression induces high, dysregulated Rac1 activity during cell spreading on fibronectin (FN) (Fig. 2B).23