CHRNA5 polymorphisms and risk of lung cancer in Chinese Han smokers

Lung cancer is the most frequent cancer among men in many countries. It is the result of interactions between genetic and environmental factors, among which tobacco smoking is a key environmental factor. CHRNA5, Cholinergic Receptor, Neuronal Nicotinic, Alpha Polypeptide-5, was previously reported to be associated with lung cancer risk. To identify the genetic susceptibility and tobacco smoking that influence lung cancer risk in Han population, we performed a case-control study in 228 patients and 301 controls. These data were compared using the x²-test, genetic model analysis, and haplotype analysis. rs495956, rs680244, rs601079, rs555018, 588765 and rs11637635 showed an increased risk of lung cancer in both allelic model and genetic mode analysis. The genotype G/A-A/A of rs11637635 was most strongly associated with a 2.17-fold increased risk of lung cancer in dominant model (p = 0.018). One SNP, rs684513, was associated with a 0.645-fold decreased risk (p = 0.033) in allelic model analysis. By haplotype association analysis, haplotype sequences CTTATCAAAGA and GA of CHRNA5 were found to be associated with a 2.03-fold and 1.91-fold increased lung cancer risk (p < 0.05). Our results, combined with those from previous studies, suggest that genetic variation in CHRNA5 may influence susceptibility to lung cancer among Han smokers.