COL2A1 and neoplasm: Col1a1, Col1a2, Col2a1, Col3a1, and Col5a2, which were commonly found in normal ECM of mouse, pig, and human breast tissues (Figure 3), were also identified in tumor ECM (Figure 5b) in addition to Col4a2, Col5a1, Col6a1, Col6a2, Col6a3, and Col7a1.