DNA methylation changes measured in pre‐diagnostic peripheral blood samples are associated with smoking and lung cancer risk

Abstract

DNA methylation changes are associated with cigarette smoking. We used the Illumina Infinium HumanMethylation450 array to determine whether methylation in DNA from pre‐diagnostic, peripheral blood samples is associated with lung cancer risk. We used a case‐control study nested within the EPIC‐Italy cohort and a study within the MCCS cohort as discovery sets (a total of 552 case‐control pairs). We validated the top signals in 429 case‐control pairs from another 3 studies. We identified six CpGs for which hypomethylation was associated with lung cancer risk: cg05575921 in the AHRR gene (p‐valuepooled = 4 × 10−17), cg03636183 in the F2RL3 gene (p‐valuepooled = 2 × 10 − 13), cg21566642 and cg05951221 in 2q37.1 (p‐valuepooled = 7 × 10−16 and 1 × 10−11 respectively), cg06126421 in 6p21.33 (p‐valuepooled = 2 × 10−15) and cg23387569 in 12q14.1 (p‐valuepooled = 5 × 10−7). For cg05951221 and cg23387569 the strength of association was virtually identical in never and current smokers. For all these CpGs except for cg23387569, the methylation levels were different across smoking categories in controls (p‐valuesheterogeneity ≤ 1.8 x10 − 7), were lowest for current smokers and increased with time since quitting for former smokers. We observed a gain in discrimination between cases and controls measured by the area under the ROC curve of at least 8% (p‐values ≥ 0.003) in former smokers by adding methylation at the 6 CpGs into risk prediction models including smoking status and number of pack‐years. Our findings provide convincing evidence that smoking and possibly other factors lead to DNA methylation changes measurable in peripheral blood that may improve prediction of lung cancer risk.

Performance of urine cotinine and hypomethylation of AHRR and F2RL3 as biomarkers for smoking exposure in a population-based cohort

“…Several epigenome-wide studies have consistently shown that the methylation levels of AHRR and F2RL3 were the top-ranked signals associated with tobacco smoking [7, 10] and smoking-related health risks such as lung cancer[11, 12] or cardiovascular disease[13]. Therefore, in the present study, we aimed to validate the previously identified association of the methylation levels of those genes with smoking.…”

DNA methylation‐based biological aging and cancer risk and survival: Pooled analysis of seven prospective studies

“…A series of case–control studies nested within the MCCS of breast, colorectal, gastric, kidney, lung, mature B‐cell lymphoma, prostate and urothelial cancer were conducted . Cancer diagnoses were identified by linkage with the Victorian Cancer Registry and the Australian Cancer Database (Australian Institute of Health and Welfare).…”

“…A series of case-control studies nested within the MCCS of breast, colorectal, gastric, kidney, lung, mature B-cell lymphoma, prostate and urothelial cancer were conducted. [32][33][34][35] Cancer diagnoses were identified by linkage with the Victorian Cancer Registry and the Australian Cancer Database (Australian Institute of Health and Welfare). For each nested casecontrol study, controls were individually matched to incident cases (diagnosed after blood sample collection) on age using incidence density sampling (i.e.…”

“…Methods relating to DNA extraction and bisulfite conversion, and DNA methylation data processing have been described previously [32][33][34][35][36][37] and are detailed in Supporting Information.…”

Is Cellular Heterogeneity Merely a Confounder to be Removed from Epigenome-Wide Association Studies?

“…Some of the best evidence for the later life effect of the environment on DNA methylation is from Fasanelli and colleagues, who showed (by EWAS) that smoking reversibly caused hypomethylation of the AHRR and FR2L3 genes in adults and that approximately 37% of the total effect of smoking on lung cancer risk is mediated by methylation at these loci [15]. Importantly, these findings have recently been independently replicated [16]. Other EWAS have also shown that genetic predisposition to adult onset phenotypes may be mediated by DNA methylation [17,18].…”