As an essential nutrient that facilitates DNA synthesis, cell proliferation and metabolism, iron is involved in carcinogenesis. While epidemiological studies suggest a J-shaped model for the relationship of serum iron level and cancer risk with both too low and too high levels associated with increased cancer risks, the effect of genetic variants related to intracellular iron regulatory pathway and dietary iron intake on non-small cell lung cancer (NSCLC) risk is little known. In this study, we evaluated a panel of miRNA related genetic variants in iron regulatory pathway genes on the risk of NSCLC. In discovery phrase, 157 miRNA related single nucleotide polymorphisms (SNPs) from 81 genes of iron regulatory pathway were genotyped in 1656 NSCLC cases and 1486 healthy controls. Eight SNPs in 6 genes were significantly associated with risk of NSCLC. A SNP in 3’ UTR of Iron-Responsive Element Binding Protein 2 (IREB2) gene at 15q25 region was subsequently replicated in dbGaP lung cancer GWAS dataset. Combining all subjects (7,352 cases, 7,296 controls), the overall P-value was 4.9 × 10−9 (Odds ratio (OR) = 0.86). eQTL analysis showed that the SNP on IREB2 alters IREB2 gene expression (P = 3.0 × 10−11). The SNP is predicted to alter a miR-29 binding site on IREB2 gene and indeed the expression of miR-29 is inversely correlated with IREB2 expression in tumor tissues. We then determined the expression of serum miR-29a in 150 early-stage NSCLC patients and 172 healthy controls and found that miR-29a was significantly associated with higher risk of cancer (OR = 1.78, P = 0.03). By analyzing dietary intake information of the discovery population, iron intake was significantly associated with risk of NSCLC in logistic regression analysis and there was also evidence of a synergistic interaction with between the SNP and iron intake in modulating NSCLC risk (P for interaction = 0.01). Taken together, SNPs at miRNA binding sites of iron regulatory pathway genes and dietary iron intake may modify risk of NSCLC individually and jointly.
Citation Format: Liren Zhang, Yuanquing Ye, Huakang Tu, Michelle A.t. Hildebrandt, John V. Heymach, Jack A. Roth, Jian Gu, Xifeng Wu. Dietary iron intake, genetic variants in microRNA related iron regulatory pathway genes, and the risk of non-small cell lung cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 809.