The results showed that exosomes released by highly metastatic HCC cells with a high abundance of circPTGR1 could down-regulate the expression of miR449a in recipient cells and thus promoted the expression of MET, enhance the migration and invasion of HCC cells with low or no metastasis, and lead to destruction of the tumor microenvironment homeostasis and promote HCC progression. The gene discussed is MET; the disease is neoplasm.