KITWT/PDGFRAWT GIST can be divided into two main groups according to the succinate dehydrogenase subunit B (SDHB) immunohistochemical status (IHC): SDHB positive (SDHBIHC+), or type 1 GIST which, includes neurofibromatosis type 1 (NF1)-mutated GIST and some sporadic KITWT/PDGFRAWT GIST. This evidence concerns the gene NF1 and gastrointestinal stromal tumor.