CHRNA7 and non-small cell lung carcinoma: Nicotine as the main addictive and harmful chemical constituent of cigarette smoke plays a key role in lung carcinogenesis [5,6,7], which enhances proliferation, invasion, cell cycle progression, angiogenesis, and inhibition apoptosis through activation of the a7 subunit of the nicotine acetylcholine receptor (a7nAChR)-mediated signaling pathways implicated in NSCLC development [44,45,46].