COL1A1 and neoplasm: Circulating levels of extracellular matrix proteins (collagen α-1 chain (COL1A1), lumican (LUM), and extracellular matrix protein 1 (ECM1) may also be differentially affected by E+P compared with E-alone, whereas MMP2, a metalloproteinase that breaks down COL1A1, may be increased with E+P compared with E. The extracellular matrix plays a variety of physiological roles, many of which are related to cancer, including tumor invasion.