Abstract 6140: Gene-environment interactions for lifetime water arsenic exposure and bladder cancer risk in the New England Bladder Cancer study
Authors: Pomares-Millan Hugo , Koutros Stella , Rothman Nathaniel , Baris Dalsu , Schwenn Molly , Johnson Alison , Silverman Debra T. , Karagas Margaret R. , Passarelli Michael N. 
Published: March 2024

Abstract
Environmental arsenic and genetic susceptibility have both been shown to increase bladder cancer risk, yet little is known about their respective interaction. We conducted a gene-environment interaction (GxE) study to characterize lifetime arsenic exposure from drinking water, inherited susceptibility, and bladder cancer risk in the New England Bladder Cancer Study. Exposures were estimated from arsenic measured in water samples collected at home and workplace. We evaluated common single-nucleotide polymorphisms (SNPs) i) from the latest bladder cancer genome-wide association study (n= 28), ii) from candidate gene studies of arsenic or bladder cancer (n= 16 SNPs), and iii) SNPs from a large genome-wide association study of arsenic metabolism (n = 4 SNPs) as potential effect modifiers of the arsenic-bladder cancer relationship. We coded SNPs as the absence or presence of a risk/effect allele for bladder cancer or arsenic metabolism in 2,019 adults (928 bladder cancer cases and 1,091 controls) and arsenic exposures as tertiles. Odds ratios (OR) with 95% confidence intervals (CI) adjusted for age, sex, smoking status, high-risk occupation, and principal components of genetic ancestry were estimated using logistic regression models. P-values for multiplicative interaction were calculated. Out of 48 SNPs, we found evidence of interaction for 7 SNPs at the statistical significance level of P&lt;0.05. Most SNPs involved in GxE interactions are mapped to genomic regions known or suspected to function in arsenic metabolism. For the association between cumulative lifetime water arsenic (mg) and bladder cancer, the strongest evidence of an interaction was with rs1046428 (near GSTZ1 on 14q23); among those with one or two copies of the T risk allele, ORT2vsT1: 1.52, CI: 1.11 - 2.07; ORT3 vsT1: 1.44, CI: 1.05 - 1.98, Pinteraction = 0.01; among those with no risk allele copy, ORT2vsT1: 0.91, CI: 0.62 - 1.35; ORT3 vsT1: 0.97, CI: 0.65 - 1.44. For average daily water arsenic (µg/day), we found evidence of interaction among those with risk allele for rs1801133 (A/A, A/G; MTHFR on 1p36) ORT2 vsT1: 1.70, CI: 1.18 - 2.44; ORT3 vsT1: 1.53, CI: 1.06 - 2.23, Pinteraction = 0.02, in those with no copies of risk allele ORT2vsT1: 0.85, CI: 0.61 - 1.17; ORT3 vsT1: 1.11, CI: 0.79 - 1.54; and rs1801131 (G/G; G/T; MTHFR ) ORT2 vsT1: 1.59, CI: 1.14 - 2.22; ORT3 vsT1: 1.63, CI: 1.16 - 2.29, Pinteraction = 0.01, whereas in those with no risk allele ORT2vsT1: 0.84, CI: 0.59 - 1.19; ORT3 vsT1: 1, CI: 0.69 - 1.44. For 40-year lagged cumulative lifetime water arsenic (mg) and average daily water arsenic (µg/day), we found suggestive interactions with rs2234636 (SLC39A2 on 14q11), and rs1495741 (NAT2 on 8p22). Our study provides evidence of interactions between lifetime arsenic exposure and genetic variants that function in xenobiotic metabolism on bladder cancer occurrence.
Citation Format: Hugo Pomares-Millan, Stella Koutros, Nathaniel Rothman, Dalsu Baris, Molly Schwenn, Alison Johnson, Debra T. Silverman, Margaret R. Karagas, Michael N. Passarelli. Gene-environment interactions for lifetime water arsenic exposure and bladder cancer risk in the New England Bladder Cancer study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6140.