Single Cell Spatial Transcriptomics Track the Evolutionary Hierarchy and Microenvironment Remodeling During Breast Carcinoma Invasion

The progression from ductal carcinoma in situ (DCIS) to invasive breast carcinoma (IBC) critically determines patient outcomes, yet its mechanisms remain incompletely understood. Integrating single-cell RNA sequencing, spatial transcriptomics, and genomics across 28 patients with synchronous DCIS and IBC, we delineate the spatial-molecular hierarchy of this transition. Invasion is primarily driven by clonal expansion of pre-existing DCIS subclones, emphasizing transcriptional reprogramming and tumor microenvironment (TME) remodeling over acquisition of additional driver alterations. IBC cells exhibit pronounced epithelial-mesenchymal transition and metabolic reprogramming. We uncover dynamic TME remodeling at the invasive front, identifying key ligand-receptor interactions (e.g., PPIA-BSG, MDK-LRP1, CXCL12-CXCR4) facilitating basement membrane disruption, angiogenesis and immunosuppression. Deconvolution of basement membrane breach reveals four molecularly defined stages (NMFT1-NMFT4) with progressively worsening patient survival. This study establishes a unified spatial-molecular atlas of DCIS-IBC progression, highlighting clonal expansion, transcriptional plasticity and TME remodeling as key drivers of invasion.