In this regard, the inhibition of c Kit gene expression by imatinib (STI 571, Glivec), which was initially shown to be effective in the treatment of chronic myeloid leukaemia (Kantarjian et al, 2002), has more recently been found effective also against c Kit-positive gastrointestinal stroma tumours (GIST) (Miettinen et al, 2001), suggesting that other c Kit-positive tumours, in particular breast carcinomas, may respond to imatinib therapy. The gene discussed is KIT; the disease is gastrointestinal stromal tumor.