Lastly, we found that the interruption of FGF-signaling with neutralizing anti-FGF-2 mAbs in GIST T-1R cells also induced a moderate decrease in CLDN1 expression (Figure 5E), thereby revealing a close functional cross-talk between the FGFR pathway and CLDN1 in this particular IM-resistant GIST cell line. This evidence concerns the gene CLDN1 and gastrointestinal stromal tumor.