While DOG1 has been shown to be a somewhat more sensitive marker for GIST than KIT and is useful in evaluating KIT-negative tumors, one report has demonstrated that just over 1/3 of KIT-negative GIST stain positive for DOG1 [41], and evaluation of large GIST series for both markers have identified cases, including those harboring mutations in PDGFRA, that are both KIT- and DOG1-negative [42, 43]. This evidence concerns the gene KIT and gastrointestinal stromal tumor.