Imatinib (Glivec®, formerly STI571), in the US imatinib mesylate (GleevecTM), the selective inhibitor of KIT BCR-ABL and PDGFR tyrosine kinases, is the only effective and approved systemic therapy for the treatment of patients with advanced gastrointestinal stromal tumours (GISTs) (van Oosterom et al, 2001; Demetri et al, 2002). The gene discussed is KIT; the disease is gastrointestinal stromal tumor.