ABSTRACT

Background: DNA methylation markers have been associated with lung cancer risk and may identify aetiologically relevant genomic regions, or alternatively, be markers of disease risk factors or biological processes associated with disease development.

Methods: In a nested case–control study, we measured blood leukocyte DNA methylation levels in pre-diagnostic samples collected from 430 participants (208 cases; 222 controls) in the 1989 CLUE II cohort. We compared DNA methylation levels with case/control status to identify novel genomic regions, both single CpG sites and differentially methylated regions (DMRs), while controlling for known DNA methylation changes associated with smoking using a previously described pack-years-based smoking methylation score. Stratification analyses were conducted over time from blood draw to diagnosis, histology, and smoking status.

Results: We identified 16 single CpG sites and 40 DMRs significantly associated with lung cancer risk (q < 0.05). The identified genomic regions were associated with genes including H19, HOXA3/HOXA4, RUNX3, BRICD5, PLXNB2, and RP13. For the single CpG sites, the strongest association was noted for cg09736286 in the DIABLO gene (OR [for 1 SD] = 2.99, 95% CI: 1.95–4.59, P-value = 4.81 × 10–7). We found that CpG sites in the HOXA3/HOXA4 region were hypermethylated in cases compared to controls.

Conclusion: The single CpG sites and DMRs that we identified represented significant measurable differences in lung cancer risk, providing potential biomarkers for lung cancer risk stratification. Future studies will need to examine whether these regions are causally related to lung cancer.

摘要

背景：DNA 甲基化标志物与肺癌风险相关，可以识别与病原学相关的基因组区域，或者是与疾病发展相关的疾病风险因素或生物学过程的标志物。

方法：在一项嵌套病例对照研究中，我们测量了从 1989 年 CLUE II 队列中的 430 名参与者（208 名病例；222 名对照）收集的诊断前样本中的血液白细胞 DNA 甲基化水平。我们将 DNA 甲基化水平与病例/对照状态进行比较，以识别新的基因组区域，包括单个 CpG 位点和差异甲基化区域 (DMR)，同时使用先前描述的基于包年的吸烟甲基化评分控制与吸烟相关的已知 DNA 甲基化变化. 从抽血到诊断、组织学和吸烟状况，随时间进行分层分析。

结果：我们确定了与肺癌风险显着相关的 16 个单一 CpG 位点和 40 个 DMR（q < 0.05）。确定的基因组区域与包括 H19、HOXA3/HOXA4、RUNX3、BRICD5、PLXNB2 和 RP13 在内的基因相关。对于单个 CpG 位点，在 DIABLO 基因中 cg09736286 的关联最强（OR [for 1 SD] = 2.99, 95% CI: 1.95–4.59, P-value = 4.81 × 10–7）。我们发现与对照组相比，HOXA3/HOXA4 区域中的 CpG 位点在病例中被高甲基化。

结论：我们确定的单个 CpG 位点和 DMR 代表了肺癌风险的显着可测量差异，为肺癌风险分层提供了潜在的生物标志物。未来的研究将需要检查这些区域是否与肺癌有因果关系。