USP1 and cancer: Recently, abnormal circRNA expressions have been demonstrated in various cardiovascular diseases and cancers, which are related to vascular dysfunction.6, 7, 8 Knockdown of cZNF609, which is highly enriched in endothelial cells, diminished retinal vessel loss and inhibited pathological angiogenesis in vivo.9 CircRNA USP1 (circ‐USP1, also known as hsa_circ_0000080 according to circBase), which is located at chr1p31, is derived from the back‐splicing of exon 6‐8 of ubiquitin‐specific peptidase 1 (USP1) gene.