Studies have shown that exosomal circ-DB secreted by adipose cells can inhibit miR-34a by targeting miR-34a and activate deubiquitination-related USP7, reducing DNA damage and promoting the proliferation and migration of HCC cells by activating the USP7/Cyclin A2 signaling pathway, leading to tumor growth and metastasis in vivo [53]. This evidence concerns the gene USP7 and hepatocellular carcinoma.