PDGFRB and gastrointestinal stromal tumor: Because MMP3 thought RAC1b can activate NF-kB and cyclin D1 but not AKT and STAT3 [19] and IGF1R not only activates AKT but also MEK/ERK pathway, our proposed immunophenotype may confer KIT-independent IM resistance, specially, in the subset of WT or PDGFR mutant GIST patients.