MMP9 and breast cancer: reported that the high expression of LSECtin on TAMs interacts with the receptor butyrophilin subfamily 3 member A3 (BTN3A3) on cancer cells and enhances cancer stemness and growth of xenografted breast tumors.[25] Animal experiments and clinical data also show that the high expression of various factors in TAMs, including lipocalin‐2 (LCN2), matrix metallopeptidase 9 (MMP9), macrophage inflammatory protein‐1β (MIP‐1β), chitinase‐3‐like protein 1 (CHI3L1), and cyclooxygenase‐2 (COX‐2), stimulate breast cancer cell migration and invasion.[26, 27, 28, 29, 30]