AXL and lung cancer: As a result, while the AXL promoter activity was inversely correlated with the AXL mRNA levels in both lung cancer cell lines and breast cancer cell lines as determined by reporter assays (Fig. 1a,b and Supplementary Fig. 1), the AXL mRNA levels were positively correlated with its 5′-UTR reporter activity (Fig. 1c) but not its 3′-UTR reporter activity in our recent study32.