CHRNA5 and lung carcinoma: Genetic variants in CHRNA5-A3-B4, encoding the α5, α3, and β4 nicotinic acetylcholine receptor subunits, are robustly associated with smoking behaviors such as cigarettes smoked per day and nicotine dependence, as well as risks for smoking-related diseases, including lung cancer and chronic obstructive pulmonary disease [4–10].