PDGFRB and gastrointestinal stromal tumor: Direct blockade of autocrine stimulation using inhibitors of PDGFR in cell lines and xenograft models show positive results in tumors such as lung cancer [21], hepatic cancer [22], gastrointestinal stromal tumor (GIST) [23], dermatofibrosarcoma protuberans [24], and osteosarcoma, which expressed PDGFR-α on the cell surface [25].