AXL and breast cancer: In the presence of 10 μM DAPT, a concentration at which the activity of γ-secretase is blocked, we observed a specific accumulation of a ∼55-kDa AXL-CTF in all types of cancer cells tested (Fig. 1)—that is, NSCLC cells (H1299 and A549), pancreatic cancer cells (AsPC-1, Panc-1, and Panc-28), glioma cells (LN-18 and LN-229), gastric cancer cells (SGC7901 and AGS), breast cancer cells (MDA-MB-231), colon cancer cells (HCT116), and human cervical carcinoma cells (HeLa).