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Abstract

Tracing the rise of tumor chemotherapy from the discovery of the first anticancer drug, nitrogen mustard, 1 to the advent of molecular approaches sheds light on the problem of drug resistance which has dogged oncology for the past half century. A number of strategies have been advised to combat the war against cancer, eg modulators of drug resistance, noncross-resistant drug derivatives, high-dose therapy, hematopoietic stem cell transplantation, and supportive gene therapy protocols. Another way is the a priori diagnosis of drug-resistant tumors. In the past three decades efforts have been undertaken to determine the resistance profiles of tumors by testing drug response in vitro. 2,3 The advances in cell and molecular biology have opened new avenues for the characterization of drug-resistant tumors. Among the plethora of resistance mechanisms, MDR1, MRP, LRP and TOPO II attracted the attention of oncologists and the transfer from the bench to the bed is a straightforward requirement. Several laboratories from the United States and Europe have teamed up under the leadership of WT Beck (University of Illinois at Chicago, USA) and JP Marie (Hô pital d'Hotel-Dieu, Paris, France), respectively, in an effort to advise a suitable methodology for the detection of MDR in clinical routine laboratory diagnostics. 4,5 In contrast to cells with high levels of drug resistance, the balance of results presented from these workshops did rather not speak Correspondence: T