Extraneous chemerin activates CMKLR1 and releases PTEN, then the recovered PTEN regains tumour suppressor activity and inhibits Akt, resulting in suppressed migration, invasion and metastasis of HCC cells, at least partially through downregulation of MMP1.25–27 This hypothesis is supported by our observation in clinical samples, HCC cells, and animal models of HCC metastasis. This evidence concerns the gene MMP1 and neoplasm.