Monday, August 22, 2011 (Last Updated: 08/23/2011)
MONDAY, Aug. 22 (HealthDay News) -- Genetic variations in the CYP2A6 and CHRNA5-CHRNA3-CHRNB4 (CHRNA5-A3-B4) genes are together associated with an increase in cigarette consumption and nicotine dependence, and can independently and additively increase lung cancer risk, according to a study published online July 11 in the Journal of the National Cancer Institute.
Catherine A. Wassenaar, from the University of Toronto, and colleagues investigated the relative and combined associations of CYP2A6 and CHRNA5-A3-B4 polymorphisms with smoking behavior and lung cancer risk in 417 lung cancer patients and 443 control subjects. Smoking variables among different genotype groups were compared using Kruskal-Wallis tests, and logistic regression analysis was used to estimate odds ratio (ORs) for cancer risk. All statistical tests were two sided.
The investigators found that the combined CYP2A6 normal metabolizers and CHRNA5-A3-B4 AA risk group had the highest cigarette consumption and nicotine dependence. The lung cancer risk was greatest in the combined risk group (OR, 2.03), and it was even higher in those who smoked 20 or fewer cigarettes per day (OR, 3.03), suggesting that the genetic risk for lung cancer may remain high among lighter smokers.
"Variation in CYP2A6 and CHRNA5-A3-B4 was independently and additively associated with increased cigarette consumption, nicotine dependence, and lung cancer risk. CYP2A6 and CHRNA5-A3-B4 appear to be more strongly associated with smoking behaviors and lung cancer risk, respectively," the authors write.
Hematology & Oncology
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