Abstract P4-05-16: FATTY ACID PROFILE ON RED BLOOD CELL MEMBRANE PREDICT BREAST CANCER SUBTYPE

Abstract Introduction. Metabolic reprogramming is a hallmark of cancer development and progression. Regarding breast cancer (BC) limited evidence assert an association between metabolic changes and its impact on BC biology and subtype. Yet no clear data has evaluated the link between lipid metabolism, measured through red blood-cell membrane (RBCm) composition, and BC subtype determination. Because RBC are the main circulating cells and 90% of its surface is membrane, the fatty acid (FA) measurement on the RBCm seems to be a good marker for FA body status and BC cell relationship with systemic normal cells. Our study sought to determine if RBCm FA profiles, determined on a routine blood sample, could predictBC subtypes in non-metastatic BC patients. Methods. A prospective study assessing FA levels (Saturated:SFA; monounsaturated: MUFA, and polyunsaturated: PUFA) on RBCm from baseline peripheral blood samples obtained in BC patients, prior systemic or local treatments. The primary objective was to determine the relationship between FA lipidomic profiles measured in the RBCm and the four main BC subtypes, defined by the IHC of diagnostic biopsy. Subtypes were classified based on estrogen receptor positive (ER) and epidermal receptor growth factor type 2 (HER2) status determinations:ER+/ HER2-, ER+/HER2+, ER-/HER2+ and ER-/HER-. Results. A total of 77 stage I-III patients with BC were included. Regarding CcClinico pathological variables measured include (age, body mass index, histological grade, Ki67 andor stage). An elevated total SFA, and lower MUFA showed a significant association with ER+/HER2- BC (p= 0.0028). No differences for total FA values were found for other BC subtypes. Regarding specific FA analysis, the concentration of PUFAs alpha-linolenic acid (C18:2n6c, linoleic (ALA), p= 0.0001), C18:3n3 (a-linolenic, p= 0.0000), C20:5n3 (EPA, p= 0.0009) and C22:6n3 (DHA, p= 0.0000) were differentially expressed based on IHC subtypes. Conclusions: RBCm FA profile determination showed a significant diagnostic potential as a biomarker for BC subtype in non-metastatic BC. Measuring FAs in RBCm could offer a convenient, minimally invasive strategy to identify BC subtypes. Further research is needed necessary to validate the performance of FAs and their thresholds using an independent dataset for cross-validation to ensure robustness. Citation Format: Francisco Acevedo, Rodrigo Valenzuela, Benjamín Walbaum, Camila Farias, Catalina Vargas, Mauricio Camus, Francisco Dominguez, Marisa Abud, Lidia Medina, Tomas Merino, Carolina Ibañez, Alejandra Parada, Cesar Sanchez. FATTY ACID PROFILE ON RED BLOOD CELL MEMBRANE PREDICT BREAST CANCER SUBTYPE [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2024; 2024 Dec 10-13; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(12 Suppl):Abstract nr P4-05-16.