CHI3L1 and Cowden disease: Furthermore, a number of other faecal biomarkers of promising utility for discriminating endoscopic CD activity have been described in the literature with the potential to be incorporated more widely into routine clinical practice, including faecal lactoferrin (FL), faecal immunochemical test (FIT), neopterin, metalloprotease-9 (MMP-9), myeloperoxidase, faecal lipocalin-2 (FCLN-2), chitinase 3-like 1 (CHI3L1), polymorphonuclear neutrophil elastase (PMN-e), microRNA, S100A12, and alpha-1 antitrypsin.