PECAM1 and neoplasm: Lentivirus‐mediated knockdown of circ‐CUX1 significantly reduced the growth, tumor weight, Ki‐67 proliferation index, and CD31‐positive microvessels of subcutaneous xenograft tumors (Appendix Fig S11A and B), with altered expression of circ‐CUX1 target genes (Appendix Fig S11C).