CCND1 and central nervous system cancer: According to this theory, some circRNAs, such as hsa_circ_0000092/miR-338-3p in hepatocellular carcinoma (23), hsa_circ_0088732/miR-661 in glioma (24), circRNA-AKT1/miR-942-5p in cervical cancer (25), as well as circRASSF2/miR-302b-3p (26), and circ-CCND1/miR-646 in LSCC (27) can act as ceRNAs, interacting with miRNAs, thus reducing its negative regulatory effect on specific mRNA (28).