CHRNA5 and lung cancer: Genes significantly contributing to the neuroactive ligand-receptor interaction pathway are highly relevant to lung cancer and have diverse functions, such as CHRNA3 (cholinergic receptor nicotinic alpha 3 subunit), CHRNA5, GRPR (gastrin-releasing peptide receptor), SSTR2 (somatostatin receptor 2), and CHRNB4 (cholinergic receptor nicotinic beta 4 subunit).