Lung Cancer Drug, Who Can It Help?

The Question: The drug Iressa shows a rapid and often dramatic response in onlyaminority of people (about 10%)with the most common type of lung cancer -- non-small-cell lung cancer. Whyisthis drugonlyeffective for justa few people, but not most?

The Answer: It appears that people with lung cancerwho respond well to Iressahave a mutation in the gene for epidermal growth factor receptor (EGFR).

Explanation: Many cells have receptors on their surfaces for epidermal growth factor (EGF), a protein that promotes cell growth. When EGF attaches to the epidermal growth factor receptor (EGFR), it stimulates cells to grow. Iressa attaches to EGFR and thereby inhibits the attachment of EGF and stops cell growth. The mutation in EGFR corresponds to an increased signal that there is enough growth factor and this makes the cells susceptible to the drug Iressa.

Comment: This remarkable finding has already been confirmed as correct. In addition to the report in Science (see below), the same result has beenfrom a separate studyin the New England Journal of Medicine.

Barbara K. Hecht, Ph.D.
Frederick Hecht, M.D.
Medical Editors, MedicineNet.com