Abstract Introduction: Comorbidities such as obesity, Type-2 diabetes (T2D), and hypertension (HTN) are highly prevalent among under-resourced African Americans (AA) and Latinx, and they are associated with breast cancer (BC) risks and outcomes. Social determinants of health (SDOH) also have been found related to BC incidence, stage, and survival. In addition, elevated inflammatory cytokines may be an underlying factor in comorbidities that contribute to tumorigenesis and adverse cancer outcomes. Limited research has been conducted to explore the process and associations among SDOH, comorbidities, and inflammation cytokines related to BC. The purpose of this study was to fill this research gap using a sample recruited from AA and Latinx communities. Methods: This was a cross-sectional study conducted in South LA. A total of 570 AA and Latinx women with or without BC were recruited. A panel of 19 cytokines from serum samples were measured by Luminex assay. Demographic information, body mass index, comorbidities, and diagnosis/stage of BC were collected from patients’ medical records. SDOH factors were selected from the social vulnerability index (e.g., percentage of persons in poverty, unemployed, with no high school diploma) obtained through Geographic Information Systems. Chi-square tests, independent sample Mann-Whitney U tests, and Cox regression were employed to examine the associations between BC diagnosis/stages, comorbidities, and cytokines. Path analyses were adopted to further explore the associations between SDOH, comorbidities, and cytokines. Results: Among the 570 women, 45.79% had a diagnosis of BC. Over half (50.97%) had ER/PR+, HER2-, and 27.80% had triple negative BC. Results from Chi-square tests showed that a higher percentage of women with obesity (p=.001), HTN (p<.0001), and T2D (p=.024) had a BC diagnosis than those without the comorbidity. Women with obesity had significantly higher levels of Leptin, VEGFα, and MIP1b; women with HTN had significantly higher levels of VEGFα and MIP1b; and women with T2D had significantly higher levels of Leptin and TGFβ1/β2. Leptin was found significantly higher in ER/PR+ BC (p<.0001) and VEGFα was significantly higher in triple negative BC (p=.001). Increasing VEGFα and TGFβ1/β2 reduced BC disease-free survival significantly. The path model showed community poverty and education level did not affect TGFβ1/β2 directly but were indirectly associated with them through obesity and T2D status (p<.01). Community poverty level was indirectly associated with the level of MIP1b through HTN status (p<.01). Conclusions: To eliminate breast cancer disparities, effective interventions are needed that account for the social and community contexts in which women live and are treated. Interventions that target comorbidities of T2D, HTN, and obesity are important to reduce the disparities. Citation Format: Weizhou Tang, Yanyuan Wu, Jaydutt Vadgama. Social determinants of health and comorbidities increasing inflammation cytokines related to breast cancer in African American and Latinx women [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr B150.