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Estrogen may increase the movement of precancerous cells in the mouth and thus promote the spread of the disease within the oral cavity, according to an article in the January issue of Cancer Prevention Research by a team from Fox Chase Cancer Center.


As described in a news release, Margie Clapper, PhD, Co-leader of the Cancer Prevention and Control Program there, and colleagues reported earlier this year (in the June 3rd issue of the same journal) that estrogen metabolism changes after smoke exposure in the lungs and may contribute to lung cancer. To find out if estrogen influences the development of head and neck cancer, Ekaterina Shatalova, PhD, a postdoctoral fellow and first author on the paper, examined the impact of estrogen on precancerous and cancerous cells.


Estrogen was found to induce the expression of the cytochrome P450 1B1 (CYP1B1) enzyme, which is responsible for breaking down toxins and metabolizing estrogen. Interestingly, the researchers said, CYP1B1 induction occurred only in precancerous cells, not in cancer cells.


Depleting the expression of CYP1B1 diminished the ability of precancerous cells to move and divide, as compared with similar cells with normal levels of CYP1B1. Estrogen also reduced cell death in the precancerous cells, irrespective of the amount of CYP1B1 present.


"In the future we would like to find a natural or dietary agent to deplete the CYP1B1 enzyme and see if we can prevent oral cancer at the precancerous stage," Dr. Shatalova said.


"Our previous studies showed that the CYP1B1 enzyme sits at the hub of changes that occur in the lungs after smoke exposure, and we were now able to look at its role in a more direct fashion by removing it from precancerous cells of the oral cavity," Dr. Clapper said.


"We found that cells lacking it move slower. CYP1B1 could be a wonderful target in precancerous lesions of the head and neck, because by attacking it, we might stop these lesions from progressing or moving to a more advanced stage." In addition, patients diagnosed with head and neck cancer are at a high risk of developing a second primary tumor, which is associated with poorer overall survival. Finding a way to reduce these subsequent tumors could extend patients' survival.