NTSR1 and fibrosis: PCPE-1, a 55-kDa ECM glycoprotein without intrinsic proteolytic activity, containing two N-terminal CUB (complement-Uegf-BMP1) domains and a C-terminal NTR (netrin-like) domain, was found to be one of proteins related to fibrosis,[38,39] but no mass-based studies have reported on the relationship between PCPE-1 and skin fibrosis so far.