Exosomal circ-ZNF652 is upregulated in the serum and cells of patients with HCC, promoting HCC cell proliferation, invasion, and metastasis through targeting the miR-29a-3p/guanylyl cyclase domain containing 1 (GUCD1) axis (Li et al., 2020). This evidence concerns the gene GUCD1 and hepatocellular carcinoma.