Breast cancer response to neoadjuvant chemotherapy (NACT) is influenced by the tumor microenvironment (TME), particularly the presence of specific immune or stromal cell subsets. Using a meta-analytical approach combining multiple transcriptomics datasets, QuantBioMed (QBM) has identified two novel cell subsets within the TME that are predictive of favorable responses to NACT. A biomarker panel, QBM-BrCa-1 has been developed to identify the cell subsets at a protein level from formalin fixed paraffin embedded (FFFPE) tissues. As a next step, we aim to validate the marker in pre-treatment breast tumors and build a scoring system to establish its translational utility in the clinic.Accurate prediction of NACT response can significantly improve treatment planning and outcomes in breast cancer. While several biomarkers have been proposed and used (4), few are directly linked to the stromal and immune architecture at the tissue level. This study aims to validate the spatial presence and abundance of two specific cell subsets using immunofluorescence (IF) and immunohistochemistry (IHC), correlating their presence with treatment response. If validated, these markers may serve as potential tools for clinical decision-making in the management of breast cancer.