- CYP2A6 polymorphisms are associated with nicotine dependence and influence withdrawal symptoms in smoking cessation. Kubota, T., Nakajima-Taniguchi, C., Fukuda, T., Funamoto, M., Maeda, M., Tange, E., Ueki, R., Kawashima, K., Hara, H., Fujio, Y., Azuma, J. Pharmacogenomics J. (2006)