MMP1 and hepatocellular carcinoma: It has been shown that circRNA DLC1 (circDLC1) is downregulated in HCC tissues, and knockdown of KIAA1429 is able to increase the expression level of circDLC1 and reduce the interaction between HuR and matrix metallopeptidase 1 (MMP1), thereby inhibiting MMP1 expression and ultimately contributing to the inhibition of HCC progression (Liu et al., 2021b).