Similarly, tobacco smoke, a complex environmental mixture, has been linked to DNA methylation alterations in genes implicated in lung cancer susceptibility, such as those coding for Kruppel-like factor 6 (KLF6), serine/threonine kinase 32A (STK32A), telomerase reverse transcriptase (TERT), MutS homologue 5 (MSH5), actin alpha 2 (ACTA2), GATA binding protein 3 (GATA3), vesicle transport through interaction with T-SNAREs homologue 1A (VTI1A), and cholinergic receptor nicotinic alpha 5 subunit (CHRNA5) [175]. The gene discussed is CHRNA5; the disease is lung cancer.