AXL and lung carcinoma: H1299 (human lung epithelial-like adenocarcinoma line) cells, Hela (human cervical carcinoma cell line) cells, and BEAS2B (immortalized non-tumorigenic lung cancer cell line) cells were used as controls for antibody reactivity for Mertk, Axl, and Tyro3, respectively, based on previous observations in our laboratory.