Multiple-Drug Resistance in Human Cancer

Abstract
THE intensive use of chemotherapeutic agents for the treatment of cancer has resulted in the cure of many patients. Unfortunately, many cancers still do not respond to chemotherapy, and other cancers that initially do respond later become resistant. If the molecular basis of drug resistance could be understood, new types of treatment might be developed to cure these drug-resistant cancers.Drug resistance has been studied in cancer cells grown in tissue culture and selected for resistance to various therapeutic agents. With this approach, the mechanism of methotrexate resistance in cultured cells has been shown to be an increase in the . . .