Cancer biology: Summing up cancer stem cells

Are current cancer drugs targeted at the wrong kinds of cells? A pioneering approach to the development of treatments uses a mathematical model to follow how different types of tumour cells respond to therapy.The kinetics of a cancerChronic myeloid leukaemia is associated with the oncogene BCR-ABL. The tyrosine kinase inhibitor imatinib (Gleevec), in the news as the first molecularly targeted anticancer drug, acts by impairing the function of this oncogene. A study of 169 patients receiving imatinib followed the kinetics of BCR-ABL in order to develop a mathematical model of the in vivo kinetics of a cancer. Imatinib reduced the rate of leukaemic cell production, but did not appear to deplete a population of leukaemic stem cells. The model also indicates when multiple drug therapy might be more effective than imatinib alone.