CD274 and colorectal cancer: hsa_circ_0020397 has been shown to increase the expression of miR-138 targets, TERT and PD-L1, to regulate the growth of colorectal cancer cells [14], while hsa_circ_0008305 (circPTK2) has been shown to function as a sponge for miR-429/miR-200b-3p that directly targets the TIF1 3′-UTR region in non-small cell lung cancer [25].