In addition, Axl has been shown to mediate migration and invasion of glioblastoma, lung cancer and breast cancer cells by upregulating the expression of matrix metalloproteinases and promoting the transition of solid tumor cells from an epithelial to mesenchymal morphology [9, 35–38], and whether Mer functions by similar mechanisms in NSCLC remains to be investigated. Here, MERTK is linked to breast cancer.