GUCD1 and hepatocellular carcinoma: circ_0005075 promotes HCC progression via miR-431 (Li et al., 2018), and exosomal circ-ZNF652 could transfer to HCC cells to promote cell proliferation, migration, invasion, and glycolysis in HCC via the miR-29a-3p/GUCD1 axis (Li Y. et al., 2020).