LCN2 and adenoma: NGAL is a part of the lipocalin protein family and is a 23 kDa low molecular weight protein secreted by various types of human cells, which include not only activated neutrophils85 but also other tissues such as the kidneys, and cells of the gastro-intestinal and respiratory tracts.86–91 NGAL is also strongly expressed by various types of carcinomas and adenomas.