Extracellular matrix protein 1 is an extracellular protein that containing motifs with a cysteine pattern characteristic of the cysteine pattern of the ligand-binding "double-loop" domains of the albumin protein family. ECM1 is implicated in breast cancer, thyroid cancer, hepatocellular carcinoma, and other cancers, and also in ulcerative colitis Germline mutations in ECM-1 cause the genetic disease lipoid proteinosis. Autoimmune attack on ECM-1 is responsible for lichen sclerosus.