Epithelial-mesenchymal transition-induced metastasis could be a bait for natural killer cells

Recent research has shown that several mechanisms induce tumor progression and a novel cause is the escape of tumor cells from immune surveillance (1). Natural killer (NK) cells play an important role in immunosurveillance against cancer cells (2), and the immunosurveillance by NK cells involves NK cell-mediated tumor cytotoxicity, which depends on the balance between NK cell-activating and -inhibiting ligands expressed in tumor cells (3).