FGF2 and gastrointestinal stromal tumor: In concordance with this data, we found a significant increase of FGF-2 levels in the serum of IM-treated mice bearing IM-resistant GIST xenografts (Figure 6E), thereby revealing the activation of the autocrine FGF-2/FGFR loop in IM-resistant GISTs after initiation of IM-based therapy.