Acetylcholine receptor pathway and lung cancer.

Genome-wide association studies revealed chromosome regions 15q24-25 were associated with a higher risk for development of lung cancer. The 15q24-25 region encompasses the nicotinic acetylcholine receptor subunit genes (nAchR alpha3, alpha5, and beta4) that play a role in nicotine addiction. This review reports information of the acetylcholine receptor and lung cancer. In patients diagnosed with smoking-related lung cancer and who continue smoking, a negative correlation with lung cancer survival has been shown. The reduced treatment efficacy may well be explained by the pluriform effect of nicotine on tumor cell proliferation, apoptosis, epithelialmesenchymal transition, proinvasive, and angiogenic effects, which are reenforced by an autocrine/paracrine loop. Overall, there is no evidence that nicotine itself induces cancer, but nicotine promotes in vivo the growth of cancer cells and the proliferation of endothelial cells. This suggests that nicotine after initiation may contribute to the progression phase of cancer development. Continuation of smoking after lung cancer has been diagnosed should be discouraged because smoking may not only support tumor growth but also interferes with treatment.