HSPG2 and breast neoplasm: The ten most abundant core‐matrisome proteins present in the adECM included fibrillar collagens (COL12A1 and COL6A2), tenascin, fibronectin, and perlecan (HSPG2), all of which have been previously reported to be overexpressed in breast tumors.[32, 33, 34] A total of 44 differentially expressed proteins were identified in the adECM, where 25 were upregulated and 19 were downregulated compared to ndECM (Figure 5D).