NCL is a highly enriched protein in nucleoli, and its abnormal expression and localization in cancer often affect the generation, proliferation and metastasis of tumor cells, leading to the progression of cancer.[25] It was also verified that NCL can be markedly enriched by a circ0006646‐specific probe but not by an NC probe, in addition to a RIP assay that showed an obvious circ0006646 concentration by anti‐NCL (but not IgG) staining (Figure 3C,D). Here, NUCLEOLIN is linked to cancer.