In addition, nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a carcinogen derived from nicotine, is an agonist of the α7-nicotinic acetylcholine receptor (nAChR) that, when activated, favors the release of adrenaline and noradrenaline inducing cancer progression through their interaction with the β-adrenergic receptors (β-ARs) [51]. The gene discussed is CHRNA4; the disease is cancer.