MMP9 and neoplasm: These shared hub genes—which include multiple collagens (e.g., COL1A1, COL1A2, COL3A1), extracellular matrix (ECM) glycoproteins (SPARC, THBS1, TGFBI), proteoglycans (BGN, LUM, VCAN), and matrix remodelers (MMP1, MMP9, TIMP1, SPP1, POSTN)—underscore a convergent biology centered on tumor–stroma interactions in both histological subtypes.