Personalized medicine for smoking cessation will require the optimal combination of multiple genetic predictors. We previously reported genetic variants in CHRNA5 as robust predictors of cessation success and response to pharmacotherapy (1), and similar associations have been reported by a large pharmacogenetic consortium (6) which includes 8 trials including the current study. This current study shows that CYP2A6 on chromosome 19 has an effect independent of CHRNA5 on chromosome 15, suggesting that these two genetic markers represent distinct biological pathways that influence smoking behaviors. Our findings extend the recent report of an additive effect of these two genes on smoking quantity (cigarettes smoked per day) and risk for lung cancer (27).
