In contrast, a total of 43 genes were identified with significantly increased expression in metastases (≥ 2-fold compared with kidney tumors), including upregulation of genes involved in extracellular matrix (ECM) reorganization, including collagen/proteoglycan assembly (i.e., ASPN, DCN, COL6A3, and COL11A1) and disassembly processes (i.e., HTRA3, MMP2, and MMP6) in most metastatic sites, with the exception of lymph node and endocrine metastases (Figure 5B). This evidence concerns the gene MMP2 and kidney neoplasm.