Abstract 4961: Cell type-specific adipokine signaling networks in the breast tumor microenvironment uncovered by high-plex spatial imaging

Abstract Background: Adiposity is linked to adverse breast cancer outcomes, but mechanisms connecting adipose signaling to tumor progression remain unclear. Adipokines like leptin and adiponectin, and their receptors, may influence tumor behavior via paracrine and autocrine interactions across tumor, stromal, and immune cells in the breast tumor microenvironment (TME). Using high-plex spatial molecular imaging, we mapped adipokine expression and cell type-specific signaling networks to reveal adiposity-related differences in tumor biology. Methods: Single-cell spatial transcriptomics was performed using the CosMx Spatial Molecular Imager (Human 6K Panel) on breast tumors and matched adjacent tissues. Cells were segmented and classified into tumor epithelium, stroma, and immune compartments via an AI framework. LEP, LEPR, ADIPOQ, ADIPOR1, and ADIPOR2 were quantified to derive compartment-specific positivity rates, mean/very high expression, potential 5-gene co-expression, and composite adipokine signature scores and expression was compared with non-tumor cells and cells from adjacent tissues, and correlated with select clinical variables. Results: In 259 women with stage II-III breast cancer (49% postmenopausal, 47% Black, 53% Hispanic, 62% ER-positive, 17% HER2-positive), adipokine and receptor expression was consistently higher in tumor cells than stromal or immune cells. All five adiposity genes showed elevated expression in tumor cells versus stroma and immune cells. In the tumor epithelial compartment, ADIPOR1, ADIPOR2, and LEPR exhibited markedly high-end expression versus adjacent epithelium (P <10−16), defining a tumor-intrinsic adipokine receptor program. Tumor epithelial 5-gene signature scores and co-expression of ≥2 adipokine genes were enriched in a subset of tumors and modestly inversely associated with tumor size. In stroma, ADIPOR1, ADIPOR2, and LEPR formed a tightly coordinated module; stromal ADIPOR1 positivity and higher stromal adipokine signature scores were enriched in higher-grade and ER-negative tumors, indicating a grade- and subtype-linked stromal adipokine phenotype. In the immune compartment, ADIPOR1 and ADIPOR2 were broadly detectable at lower intensity, correlated with LEPR and immune-specific adipokine scores, consistent with a distinct immune-focused axis. Across compartments, 5-gene signatures captured coherent TME-wide adipokine programs remodeled in tumor versus adjacent tissue and showing compartment-specific associations with BMI, grade, ER status, and tumor size. Conclusion: Single-cell spatial profiling reveals a compartmentalized adipokine architecture in the breast TME, including a heightened tumor epithelial receptor program, a grade-linked stromal module, and an immune-associated axis that together form integrated adipokine signatures strongly connected to clinicopathologic features. Citation Format: Samarth Singhal, Amber Rockson, Hanina Hibshoosh, Parin Shah, Fatemeh Derakhshan, Diane Chen, Alireza Salem, Benjamin Izar, Kevin L. Gardner, Coral O. Omene, Daniel Fernandez, Adrienne L. Castillo, Emma Armstrong, Ijeamaka Anyene Fumagalli, Elizabeth M. Cespedes Feliciano, Sandeep K. Singhal, Adana A. M. Llanos. Cell type-specific adipokine signaling networks in the breast tumor microenvironment uncovered by high-plex spatial imaging [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 4961.