Abstract B020: DNA methylation and pancreatic cancer in select gene promoter regions: A repeated measures case-control study of US military service members

Abstract Introduction: Pancreatic cancer (PC) is a devastating disease, its etiology is not fully understood, and there is a paucity of non-invasive biomarkers for early diagnosis. While DNA methylation (DNAm) holds promise, associations between DNAm and PC risk are poorly understood, especially regarding temporal changes in associations. Therefore, we aimed to evaluate potential associations between DNAm in pre-diagnostic serum on 9 genes (BNIP3, CDKN1C, CLDN4, LCN2, p16, RASSF1, SFN, SPARC, and TFPI-2) and 2 repetitive elements (Alu and LINE-1) and PC risk in a US Department of Defense cohort. Methods : The study population included 82 PC cases, diagnosed 1991 - 2007, and 229 controls individually- matched on age (within 5 years), sex, race, and serum draw time period. Cases had up to 3 pre- diagnostic serum samples. Controls had 1 serum sample collected 0-10 years before their selection date (date of case diagnosis). DNA was extracted from serum and the percentage of cytosines at a given CpG site that were methylated was quantified via Pyrosequencing. For serum samples within a time window (<2, 2-<5, and 5-10 years pre-diagnosis), we computed odds ratios (ORs) and 95% confidence intervals (95% CIs) for the association of each CpG site with PC risk (66 sites in total across all genes and repetitive elements) with conditional logistic regression models. DNAm was evaluated as both a binary variable and a continuous variable. Results : In samples collected 5-10 years before diagnosis, those with no DNAm (0% DNAm) had increased odds of PC compared to those with DNAm (>0% DNAm) in the promoter region of BNIP3 (Chr10:131982293 OR, 95% CI: 5.63, 1.16 – 27.28) and those with lower DNAm (<median) had increased odds of PC compared to those with higher DNAm (≥median) in the promoter regions of CDKN1C (Chr11:2886398 OR, 95% CI: 4.07, 1.16 – 14.31; Chr11:2886388 OR, 95% CI: 3.51, 1.24 – 9.96) and RASSF1 (Chr3:50340841 OR, 95% CI: 3.98, 1.15 – 17.45). Similarly, in samples collected 2 - <5 years before diagnosis, lower DNAm (<median) was associated with increased odds of PC compared to those with higher DNAm (≥median) in the promoter region of TFPI-2 (Chr7:93890717 OR, 95% CI: 3.82, 1.20 – 12.15). In models with DNAm as a continuous measure and in samples collected <2 years before diagnosis, a 1% increase in DNAm in the promoter region of SFN was associated with increased odds of PC (Chr1:26863188 OR, 95% CI: 1.23, 1.01 – 1.51). There was no evidence of associations between DNAm on Alu, CLDN4, LCN2, LINE-1, p16, or SPARC and PC risk. Conclusions : Our findings of increased risk of PC associated with lower DNAm on BNIP3, CDKN1C and TFPI-2 and higher DNAm on SFN genes suggest there may be molecular patterns occurring prior to PC diagnosis that could be considered further for developing non-invasive biomarkers for early diagnosis of this aggressive carcinoma. The opinions and assertions expressed herein do not reflect the official policy or position of the Uniformed Services University, the Department of Defense, or the National Cancer Institute. Citation Format: Jordan McAdam, Ruth M Pfeiffer, Alexander P Keil, Ann Meyer, Anwar E Ahmed, Dechang Chen, Jennifer Rusiecki. DNA methylation and pancreatic cancer in select gene promoter regions: A repeated measures case-control study of US military service members [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr B020.