by Jung-Chen Su, Chen-Ling Lee, Fan-Wei Yang, Yan-Chih Chen, Te-Lun MaiTriple-negative breast cancer (TNBC) is an aggressive and heterogeneous subtype of breast cancer, with limited treatment options due to the absence of estrogen receptors, progesterone receptors, and human epidermal growth factor receptor 2 (HER2) expression. This characteristic renders TNBC resistant to hormone-based and HER2-targeted therapies, leaving cytotoxic chemotherapy as the predominant strategy and highlighting the urgency for novel interventions. In this study, we investigated the mechanism of action of GL24, a potent 4-(phenylsulfonyl)morpholine-based small molecule with selective tumor suppression effects on metastatic TNBC cells, while being ineffective against TNBC cells derived from the primary tumor site, using gene co-expression analysis. By considering the distinct phenotypic responses induced by GL24, we tailored our co-expression analysis approach, selecting gene pairs that exhibited differential co-expression in effective cells while excluding gene pairs that also showed differential patterns in non-effective cells. Constructing a co-expression network from these differential pairs, followed by enrichment analysis and functional annotation, revealed specific gene interactions and molecular pathways associated with GL24-mediated TNBC inhibition. These insights supported the previously established findings that showed convergence on apoptosis based on differentially expressed genes, while also providing complementary information by highlighting pathways involved in metabolic alterations, proliferation, and migration or invasion. This expanded understanding advances the knowledge of the mechanisms of GL24 in combating TNBC.