Targeted molecules in small cell lung cancer.

Because small cell lung cancer is decreasing in frequency in North America, the tempo of clinical trials in general and investigation of molecular-targeted therapy is less active than for non-small cell lung cancer. Nevertheless, progress in the understanding of the molecular pathogenesis of small cell lung cancer has been substantial. Potentially relevant molecular targets have been identified and drugs have been developed to exploit them. This article discusses the common expression of c-Kit receptor tyrosine kinases in small cell lung cancer and its potential to serve as an effective target for small-molecule inhibitors such as imatinib mesylate. Another innovation described is the development of an immunoconjugate (BB-10901) that links an antibody targeting the CD56 antigen of the neural cell adhesion molecule family with a potent maytansinoid cytotoxic component. These novel strategies are currently in clinical trials and potentially will allow additional therapeutic options for patients resistant to conventional strategies. Should these proof-of-concept studies show promise, integration of these agents with conventional modalities in previously untreated patients will follow.