Consistent with these studies, our data indicated increased DDR1 expression in breast cancer liver metastasis mice, which was decreased after EFL1 treatment via T lymphocytes infiltration; however, overexpression of DDR1 abolished EFL1-induced anti-liver metastasis function in breast cancer, suggesting that EFL1-induced anti-liver metastasis effect relies on DDR1 inhibition in mice with breast cancer. Here, EFL1 is linked to breast cancer.