According to the studies of circRNAs in CRC, hsa_circ_0001649, hsa_circ_0004585, hsa-circ-0004771, circ-CCDC66, circ-ABCC1, and circ-STIL are non-invasive diagnostic biomarkers for CRC, and hsa_circ_0007534, hsa_circ_0000370, hsa_circ_0082182 hsa_circ_0035445, hsa_circ_0002320 and circVAPA can be applied for CRC diagnosis and prognosis. This evidence concerns the gene CCDC66 and colorectal carcinoma.