CD274 and neoplasm: Other studies have shown that circRNAs play a variety of roles in the TME, promote or inhibit the immune system and angiogenesis, improve the permeability of endothelial cells, promote tumor metastasis, lead to ECM remodeling, and jointly support tumor progression (14, 15)—for example, CAFs can release circEIF3k under hypoxia, upregulate miR-214, and downregulate the programmed death ligand-1 (PD-L1) expression in colorectal cancer, thus inhibiting the progression of colorectal cancer (16).