Resistance mechanisms in human lung cancer.

Drug resistance is an important problem in the treatment of lung cancer. Patients become resistant not only to the drugs used initially, but also to those to which they have not yet been exposed. Multiple mechanisms contribute to drug resistance in this disease, all or any combination of which may occur simultaneously within each cell, producing an overall drug-resistant phenotype. The limited success of hitherto applied strategies in their ability to circumvent drug resistance in lung cancer suggests that new approaches are required.