One such secretome biomarker present in the bile secreted by the cholangiocarcinoma is the neutrophil gelatinase-associated lipocalin (NGAL), a 25-kDa glycoprotein that forms a covalently linked complex with the 92-kDa type-IV gelatinase matrix metalloproteinase-9 (MMP9). Here, LCN2 is linked to cholangiocarcinoma.