Cigarette Smoke Linked to Lung Cancer Mutation

Researchers have found that benzo(a)pyrene diol expoxide (BPDE), a known carcinogen in cigarette smoke, causes mutations in the RAS gene, a finding that demonstrates a direct molecular link between smoking and lung cancer. The finding was reported in the October 16, 2002, issue of the Journal of the National Cancer Institute.

RAS is a family of genes that have many biological functions but mainly control cell growth and development. Mutations in a RAS gene can lead to uncontrolled cell growth, and more than 30% of lung cancers, 90% of pancreatic cancers, and 50% of colon cancers are associated with mutations at a specific site in the K-RAS gene.

Using a sensitive gene mapping technique, investigators from New York University School of Medicine (NYU, USA) showed that BPDE preferentially bound to the K-RAS gene at codon 12, an area especially vulnerable to mutation and only marginally repairable. In addition, they found that BPDE did not bind significantly to other members of the RAS gene family.

Dr. Eric Moon-shong Tang, professor of environmental medicine at NYU School of Medicine, explained that the findings provide further proof that smoking does cause lung cancer because the carcinogen bound most strongly to the precise site in the K-RAS gene that is frequently mutated in lung cancer.



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New York University Med. Center