Lazarus response. a new study explains why Iressa clears lung tumors in a minority of patients.
Lung cancer is the leading cause of cancer death, killing about 0,000 people in the US each year. Recently, however, a new drug called gefitinib (Iressa) gave patients a glimmer of hope, while presenting a puzzle: Iressa shrinks tumors in only about 10% of patients who take it, but when it works not, clinicians say, it works surprisingly well. New research provides an explanation. - And can lead to better treatments for lung cancer and perhaps other cancers as well
In an article published online by Science April 29, researchers Harvard Dana-Farber Cancer Institute in Boston report that tumors of patients who respond to Iressa carrying mutations in one of their proteins, the receptor by which epidermal growth factor (EGF) triggers cell growth. In addition, Daniel Haber and Massachusetts General Hospital colleagues in Boston reported very similar results in a paper that will appear in the May 20 issue of The New England Journal of Medicine and is also published online this week. The work suggests that mutations stimulate the growth of lung cancer and Iressa - that inhibits the activity of the EGF receptor. - Checks growth
of the EGF receptor is a kinase, an enzyme that regulates protein by binding phosphate groups to them. Both groups discovered that mutations cluster near the catalytic active site of the receptor kinase, which is also the case Iressa binds. Experiments on cultured cells by Haber and his colleagues showed that the mutant receptors "signal at a higher level in response to EGF and do not turn off." Thus, the mutations may confer a growth advantage to tumor cells while making them much more susceptible to the mutant EGF receptor Iressa.If really means how well Iressa is likely to work, "it would be the single most important finding in genetic never lung cancer, "says David Carbone specialist lung cancer from Vanderbilt University school of medicine. clinicians should now be able to screen patients with newly diagnosed lung cancer to see if their tumors carry mutations in the EGF receptor and therefore are good candidates for Iressa therapy. patients could then take the medication immediately in hopes of staving off lethal tumor growth, instead of late in the disease as has often been the case so far that the new findings are good news for some patients with lung cancer, they are something of a mixed bag Iressa could be taken for life - a .. cost from $ 2,000 to $ 3,000 a month. And the market for Iressa seems likely to reduce - not what the manufacturers want to hear. On the positive side, however, the EGF receptors on other types of tumor cells could lead to similar changes, which Iressa case could be used to treat, too.
Related Sites
on science xpress paper
on NEJM article
Lung resources on cancer of the National cancer Institute
0 Komentar