In in vitro experiment, downregulation of NR4A3 markedly restored the EMT, migration, and invasion of BC cells inhibited by miR-665 inhibitor; in BC metastasis model in nude mice, NR4A3 is significantly reduced in the metastatic nodules formed from BC cells with miR-665 overexpression (Fig. 6c), indicating that miR-665 promotes EMT, migration, invasion, and metastasis of BC cells by targeting NR4A3. Here, NR4A3 is linked to breast cancer.