Advance in the understanding of the role of tobacco carcinogenesis

Tobacco smoke causes the production of COX-2, a related to the development and progression of cancer cell protein, according to a study published in the journal "Cancer Research".

Andrew J. Dannenberg and colleagues at Cornell University in Philadelphia have found that the amount of COX-2 was higher in the oral mucosa of smokers than in non-smokers. To understand the mechanism underlying this phenomenon, the researchers exposed in vitro cells to cigarette smoke.

They were able to determine that higher levels of COX-2 induced by cigarette smoke lead to an activation of the EGFR receptor cell growth factor also associated with several types of cancers.

Tobacco smoke also appears to stimulate the cells of the oral mucosa to produce two proteins that activate the EGFR, initiating a cascade of reactions resulting in the production of COX-2 protein.

"We were able to block the induction of COX-2 with either a small molecule inhibitor of the EGFR activity or an antibody preventing ligands bind and activate EGFR. These findings lead us to ask if tobacco smoke initiates the process or increase the production of COX-2 by stimulating the production of first protein controlling the activity of the EGF receptor, "says Dr. Dannenberg.

Both proteins are produced Amphiregulin and TGF-alpha. Based on the work of researchers, production occurs shortly after exposure to cigarette smoke, seems to confirm the hypothesis that oral biopsies from smokers, they have revealed the presence of two proteins.

"These results provide new insights into the mechanism by which tobacco smoke causes cancer development. Mutations occur only in proliferating cells and activation of the EGFR signaling enhances cell proliferation" says Dr. Dannenberg.

According to him, the approaches to reduce the risk of malignant tumors of the mouth and throat associated with smoking should therefore not target only COX-2 but also EGFR.