We determined piR-823 expression levels in the serum samples of 47 male and 37 female CRC patients of age 59.12 ± 2.61, 40 male and 35 female healthy controls of age 61.22 ± 3.31, and in biological tissues specimens obtained from the 84 patients with colorectal cancer including core tumor tissues and neighboring normal healthy tissues to detect the expression level of piR-823 and test the feasibility of using it as a tumor marker. This evidence concerns the gene PIR and colorectal cancer.