CHRNB4 and lung carcinoma: In 2012, Ito et al. demonstrated that variants located in the CHRNA5-CHRNA3-CHRNB4 cluster on chromosome 15q25 (rs12914385, rs1317286, and rs931794) modified the impact of cigarette smoking on lung cancer risk in a Japanese population but demonstrated no statistically significant primary effects on lung cancer risk [11].