AXL and triple-negative breast carcinoma: Moreover, these studies provide a rationale for the metastatic activity of Axl, whereby EGFR-Axl expressing cells preferentially activate a tumorigenic signature that promotes cytoskeletal reorganization, motility, invasion, and in vivo, Axl knock-out in the triple negative breast cancer cell line 4 T1 showed impaired tumor growth and subsequent decreased frequency of metastasis to the lung.