NC10 stands for Non-helical region 10 and is taken from COL15A1. A mutation in this region in COL18A1 is associated with an increased risk of prostate cancer. This domain is cleaved from the precursor and forms endostatin. Endostatin is a key tumor suppressor and has been used highly successfully to treat cancer. It is a potent angiogenesis inhibitor. Endostatin also binds a zinc ion near the N-terminus; this is likely to be of structural rather than functional importance according to.