PPBP and nasopharyngeal carcinoma: Other chemokine, such as CXCL5 has been described to promote EMT of nasopharyngeal carcinoma cells by activating ERK/GSK-3β/snail signaling (50), and previous report mentioned that PPBP is able to promote proliferation and invasion of carcinoma cells (51), suggesting the possibility of an PPBP-regulated mesenchymal transition.