CCND1 and osteosarcoma: Growing evidence indicates that miR‐646 plays a tumour‐suppressive role in a variety of human cancers, including osteosarcoma,22 hepatocellular carcinoma23 and gastric cancer.24 Likewise, we found that miR‐646 was remarkably up‐regulated after oncogenic circ‐CCND1 depletion, and knockdown of miR‐646 significantly rescued the decreased proliferation rate induced by circ‐CCND1 silencing, implying that miR‐646 may be also an anti‐cancer gene in LSCC.