Here we report the analysis of activating mutations in codon 816 of c-KIT in 31 patients with a GB and/or dysgerminoma by LightCycler analysis, together with conventional sequence analysis of c-KIT exons 8, 9, 11, 13 and 17, and PDGFRA exons 12, 14 and 18, mutations in which are frequently found in GIST. The gene discussed is KIT; the disease is gastrointestinal stromal tumor.