KIT and gastrointestinal stromal tumor: In view of the evidence of KIT mutations in GIST and their possible prognostic value (as well as their relation to imatinib therapeutic response) (Lasota et al, 1999; Heinrich et al, 2003), exons 9, 11, 13, 17 of KIT (which are those related to prognosis in the literature) were analysed in the same methodological manner.