Study Supports Cigarette - Cancer Link

WASHINGTON: Prices of tobacco shares tumbled Friday as investors reacted to a report of new scientific evidence linking cigarettes to lung cancer. The study, published in the journal Science strongly linked cigarettes to lung cancer and may force the tobacco industry to rethink its argument that no clear connection has been established between smoking and the disease. The research found a tobacco carcinogen called BPDE bonds to three molecular sites on a gene crucial to the development of cancer. The gene, known as P53, monitors DNA copying during cell division and destroys cells with defective copies of genetic material. When BPDE adheres to the gene through cigarette smoking, however, it becomes damaged and cannot eliminate abnormal cells. As a result, cells with incorrect DNA divide and produce cancer. Although BPDE has long been viewed as a possible carcinogen, its role is now firmly established, said Moon-shon Tang, the study's lead author. "Until now we did not know (BPDE) binds with the spots on the P53 gene that are associated with lung cancer," he said. "In essence, our study provides a direct link between a defined cigarette-smoke carcinogen and human cancer mutations." Cigarette companies have maintained no firm correlation between cigarettes and cancer exists. But many anti-smoking activists say this new study, in combination with earlier research, makes the industry's argument implausible. "(The study) provides the last link, the smoking gun, if you will, on the issue that smoking causes lung cancer," said John Banzhaf, director of the anti-tobacco group Action on Smoking and Health. Banzhaf also said the study represents a powerful weapon in lawsuits against the tobacco companies. The FDA and representatives from the tobacco institute declined comment on the findings. -->