Several biomarkers are reported for AKI, including neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule 1 (KIM-1), L-type fatty acid-binding protein (L-FABP), cystatin C, Clusterin, interleukin-18 (IL-18), Proenkephalin A 119–159 (Penkid), the product of insulin-like growth factor binding protein 7 (IGFBP-7), and the tissue inhibitor of metalloproteinase 2 (TIMP-2). This evidence concerns the gene TIMP2 and acute kidney injury.