Imatinib (STI571), a receptor tyrosine kinase inhibitor with effects on the bcr-abl tyrosine kinase, platelet-derived growth factor receptor (PDGFR) and c-KIT is now standard treatment in patients with chronic myeloid leukaemia and the rare gastrointestinal stromal tumours (GIST) (Druker et al, 2001; Demetri et al, 2002). The gene discussed is PDGFRB; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.