Abstract 2521: New predictive markers for dasatinib responsiveness in triple-negative breast cancer: A biomarker discovery study

Abstract Triple negative breast cancer is the most heterogeneous and aggressive type of breast tumor type and is characterized by the lack of expression of clinical biomarkers (ER, PR, and HER2) and targeted therapies. In this regard, different clinical trials have failed, unable to stratify these patients to find an effective response to specific therapy. This study aimed to identify biomarkers exclusively expressed in the basal mammary compartment that can help us to subclassify the triple-negative breast cancer subtype. Based on computational analysis from single-cell RNA sequencing data, we have identified a list of basal identity-associated genes (BC-markers). Subsequent histological validation confirmed the expression pattern of these markers in a cohort of 50 samples, which has allowed us to stratify triple-negative breast cancer patients into BC-TNBC and luminal-like subtypes. Importantly, the expression of these markers correlated with poorer prognosis in TNBC patients. Functional analysis revealed that TAGLN played a significant role in cell proliferation and migration, potentially impacting tumor aggressiveness. Moreover, the expression of these BC-markers is associated with a mesenchymal phenotype which corresponds to the previously described Lehmannn’s mesenchymal-like signature. In this study, TAGLN appeared to influence dasatinib sensitivity, suggesting its potential as a predictive biomarker for dasatinib response in TNBC patients. Citation Format: Daniel Ortega-Álvarez, David Tebar, Marta Casado, Elena Castillo, Cristina Guardia, David Olivares-Osuna, Eva Musulén, Elisabetta Mereu, Ginés Luengo, Eva M. Galán-Moya, Veronica Rodilla. New predictive markers for dasatinib responsiveness in triple-negative breast cancer: A biomarker discovery study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2521.