CD74 and breast ductal adenocarcinoma: Following data preprocessing, we clustered cells based on their gene expression profiles using K-means clustering, as illustrated in Figure 1A. Figure 1B–E depicts the normalized expression levels of CD68 (a macrophage marker), CD74 (a marker for myeloid-derived suppressor cells [MDSCs]), LAMP1, and FXYD3 (a ductal carcinoma marker) across all cells.