Abstract C080: Neighborhood disadvantage and biological aging biomarkers among breast cancer survivors
Authors: Shen Jie , Zhao Hua , Fuemmeler Bernard , Sheppard Vanessa , Bear Harry 
Published: January 2023

Abstract
Living in a disadvantaged neighborhood is associated with adverse outcomes among breast cancer patients, but the underlying pathway is still unclear. Limited evidence has suggested that accelerated biological aging may play an important role. In this study, we attempted to take the first step by evaluating the relationship between neighborhood disadvantage and biological aging biomarkers among breast cancer patients. Using a sub-sample of 906 women with newly diagnosed breast cancer at M.D. Anderson, we examined whether levels of selected biological aging biomarkers (allostatic load (AL), telomere length, and global DNA methylation) were affected by neighborhood disadvantage. The Area Deprivation Index (ADI) was used to measure the levels of neighborhood disadvantage. Telomere length and global DNA methylation in leukocytes were measured by qPCR and ELISA, respectively. We used 17 factors that represent the activity of five physiological systems to construct the AL score. Based on the median ADI at the national level, the study population was divided into low and high ADI groups. Overall, breast cancer patients from the high ADI group were more likely to be younger and non-Hispanic Black than those from the low ADI group (P&lt;0.001, respectively). They were also more likely to have higher stage and poorly differentiated breast tumors (P=0.029 and 0.019, respectively). For the relationship with markers, compared to the low ADI group, high ADI group had higher median levels of AL (P=0.046) and lower median levels of global DNA methylation (P&lt;0.001). Compared to their counterparts, those from the high ADI group were 20% more likely to have increased AL and 51% less likely to have increased levels of global DNA methylation. Additionally, we found that the significant associations of AL and global DNA methylation with ADI group were observed in non-Hispanic Whites and Blacks, but not in Hispanics. Lastly, using the mediation analysis, we found that decreased global DNA methylation mediated 6.52 and 7.98% of the association between higher ADI group with stage III and poorly differentiated tumor (P = 0.037 and 0.023), respectively. In summary, we observed that neighborhood disadvantage was associated with more aggressive breast tumor characteristics, and influenced the levels of AL and global DNA methylation among breast cancer patients. Our findings suggest that neighborhood disadvantage is biologically embedded in molecular level and associated with accelerated biological aging among breast cancer patients.
Citation Format: Jie Shen, Hua Zhao, Bernard Fuemmeler, Vanessa Sheppard, Harry Bear. Neighborhood disadvantage and biological aging biomarkers among breast cancer survivors [abstract]. In: Proceedings of the 15th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2022 Sep 16-19; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr C080.