In addition, nAChR subunit-encoding gene cluster CHRNA5-A3 may have function in chemotherapy resistance to gemcitabine, cisplatin, and paclitaxel in NSCLC through the Akt-dependent proliferation and the NF-kappaB-dependent survival pathways under the stimulation of NNK [16–18]. This evidence concerns the gene CHRNA5 and non-small cell lung carcinoma.