When EVs derived from highly metastatic 4THM (4T1 heart metastases) murine breast cancer are infused into mice bearing less metastatic EMT6 breast cancer tumors, the EMT6 tumors also become highly metastatic, a process thought to be facilitated through the enhanced secretion of IL-6 (Gorczynski et al., 2016). This evidence concerns the gene IL6 and breast cancer.