Intratumoral polymorphonuclear granulocyte is associated with poor prognosis in squamous esophageal cancer by promoting epithelial-mesenchymal transition

Aim: The role of polymorphonuclear granulocyte (PMN) infiltration in tumor remains unclear in esophageal cancer (EC). Materials & methods: We conducted a retrospective study on consecutive patients with primary squamous EC. The potential roles of PMN infiltration into tumor nests were assessed by immunohistochemistry. The interactions of PMNs and tumor cells were investigated in an in vitro coculture system. Results: Intratumoral PMN is an independent prognostic factor. PMN infiltration induces epithelial-mesenchymal transition of cancer cells with the initiation of TGF-beta/Smad signaling pathway. Conclusion: Our study demonstrates intratumoral PMN is an independent unfavorable predictor in squamous EC. PMN promotes cancer progression partly by its ability to induce epithelial-mesenchymal transition via TGF-beta/Smad signaling pathway.