Table 1.

Characteristics of biomarkers.

Biomarkers	Discovery	Nature	Signaling pathways
Asymmetric dimethylarginine	Vallance et al., 1992 first reported the role of asymmetric dimethylarginine	It is a metabolic by-product chemical found in blood plasma	It involves in transforming growth factor-beta, nuclear factor-κB and Mitogen-activated protein kinase signaling pathways
Clusterin	Fritz et al., 1983 was first identified in ram rete testis fluid.	75–80 kDa disulfide-linked heterodimeric protein	It involves in transforming growth factor-beta, signaling pathway
Neutrophil gelatinase-associated lipocalin	Kjeldsen et al., 2000 first identified this protein as a component of neutrophil granules	25 kDa protein and expressed in neutrophils	It involves in Epidermal growth factor receptor and Mitogen-activated protein kinase signaling pathways
Hepatocyte growth factor	Nakamura et al., 1984 first identified and purified Hepatocyte growth factor in rat	It is secreted as a single inactive polypeptide and consists of 69-kDa alpha-chain and 34-kDa beta-chain	It involves in phosphatidylinositol 3-kinase-Akt, growth factor-beta, nuclear factor-κB and the Stat3 signaling pathways