The concept of molecular targeting as a tool in the development of cancer therapies is gaining increasing prominence, and the tyrosine kinase inhibitor STI 571 ['Glivec'] seems to have become a poster child for the concept. The results seen with STI 571 in clinical studies have borne out the viability of the molecular targeting approach. Positive data from numerous studies involving the agent were presented at the 42nd Annual Meeting of the American Society of Hematology*(ASH) [San Francisco, US; December 2000]. In particular, researchers were proclaiming the potential importance of STI 571 for the treatment of chronic myeloid leukaemia (CML), following on from the promising results presented at the 1999 ASH meeting.**