KIT and neurofibromatosis type 1: On the other hand, NF1 patients, regardless of whether there is positive staining for KIT immunohistochemically, are known to have an absence of c-kit gene mutations, and the pathogenesis of GISTs among sporadic and NF1 populations is considered different; however, their distinctions in biological malignancy degree and survival prognosis remain to be elucidated [30].