Herein, in metformin-treated human osteosarcoma cells, for the first time, we identified miR-570-3p as a tumor suppressor gene, which inhibited the metastasis and autophagy by targeting LCMR1(lung cancer metastasis-related protein), known as Med19 in human, which is crucial in the metastasis of various human tumors49–51, and another gene, autophagy-related gene 12 (ATG12), which is an autophagy marker that is significant for the development of many types of tumors. This evidence concerns the gene MED19 and cancer.