Anthracycline resistance in breast cancer: clinical applications of current knowledge.

Anthracyclines are highly effective antineoplastic agents for the treatment of breast cancer. Nevertheless, essentially all breast cancer patients have tumours which are intrinsically resistant or which develop resistance during the course of therapy. Clinical trials provide indirect information on the nature of anthracycline resistance and work in the basic sciences has demonstrated molecular mechanisms which play a role. Initial clinical attempts to exploit and translate these mechanisms to predict, and interfere with, anthracycline resistance have met with mixed success, and have not yet led to accepted clinical applications.