CHRNA4 and lung carcinoma: Recently, several single nucleotide polymorphisms (SNPs) in two nAChR subunit-encoding gene clusters (rs1051730, rs16969968 and rs8034191 in CHRNA5-A3 and rs13280604 in CHRNB3-A6) were shown to be associated with lung cancer risk and smoking consumption in Caucasians by genome-wide association (GWA) studies [9–12].