Affiliation: Dept of Pharmaceutical and Biological Chemistry, School of Pharmacy, University of London, 29-39Brunswick Square, London WC1N 1AX.
Resistance remains a major problem in the clinical utility of cancer chemotherapy. However, it also represents a tumour cell phenotype that is in many ways different, and thus distinguishable, from the majority of normal cells. Two approaches to the targeting of resistant cells are described involving intratumoral P450 expression, mechanisms of drugefflux and defective DNA repair. It is suggested that the view of the solid tumour as a complex organ rather than a collection of individual cells will inform future drug development and both overcome and target multiple resistance mechanisms.