For example, as observed in this systematic review, the level of fecal miR-451 increased significantly in the presence of blood even at low concentrations (0.1 mg Hb/g stool), and miR-451 achieved a high diagnostic performance for CRC with an AUC of 0.97 (88% sensitivity, 100% specificity). This evidence concerns the gene GSTM1 and colorectal carcinoma.