SOX2 is really a core pluripotency-connected transcription factor causally associated with cancer initiation, aggressiveness, and drug resistance by driving the self-renewal and seeding capacity of cancer stem cells (CSC). Here, we tested ale the proven inhibitor from the lysine-specific demethylase 1 (LSD1/KDM1A) iadademstat (ORY-100) to focus on SOX2-driven CSC in cancer of the breast. Iadademstat blocked CSC-driven mammosphere formation in cancer of the breast cell lines which are determined by SOX2 expression to keep their CSC phenotype. Iadademstat avoided the activation of the LSD1-targeted stemness-specific SOX2 enhancer in CSC-enriched 3-dimensional spheroids. Using high-throughput transcriptional data offered by the METABRIC dataset, high expression of SOX2 was considerably more prevalent in luminal-B and HER2-enriched subtypes based on PAM50 classifier as well as in IntClust1 (high proliferating luminal-B) and IntClust 5 (luminal-B and HER2-amplified) based on integrative clustering. Iadademstat considerably reduced mammospheres formation by CSC-like cells from the multidrug-resistant luminal-B cancer of the breast patient-derived xenograft although not of individuals from the treatment-na?ve luminal-Someone. Iadademstat reduced the expression of SOX2 in luminal-B although not in luminal-A mammospheres, likely indicating a selective targeting of SOX2-driven CSC. The therapeutic relevance of targeting SOX2-driven breast CSC suggests the possibility clinical utilization of iadademstat being an epigenetic therapy in luminal-B and HER2-positive subtypes.