CHRNA3 and lung cancer: There are many common genetic variants in the loci of chromosomes 4 (HHIP and FAM13A) [21] and 15 (CHRNA3/5 and IREB2) [6,29] that display roles in the development of COPD, and the CHRNA3/5 locus that is associated with smoking addiction [10] which results in smoking-related lung diseases, such as COPD and lung cancer.