Our third significant single-SNP finding is at the 5′ end of CHRNB3-CHRNA6, tagged by rs13277254, and here again the functional source of this signal is unclear. Interestingly, a study in non-small cell cancer tumors found higher expression of CHRNA6 and CHRNB3 in non-smokers compared to smokers (Lam et al., 2007), suggesting potential mechanisms of action related to exposure to smoking and nicotine dependence.
