With the advent of the cancer-focused Illumina GoldenGate methylation platform, several groups examined genome-wide differences in methylation patterns in smokers versus non-smokers. In lung tissue, Christensen and colleagues [43] found a significant effect of pack years smoked on human mutL homolog 1 (MLH1) and receptor-interacting serine-threonine kinase 3 (RIPK3) methylation, and 138 loci in total with altered methylation in lung tissues of ever versus never smokers. Breton and colleagues [44] found differences in global methylation of LINE-1 and validated hypermethylation at two loci (tyrosine-protein kinase receptor UFO, receptor-type tyrosine-protein phosphatase O) by confirmatory pyrosequencing in buccal samples of children exposed versus non-exposed to smoking during pregnancy.
