Tumor-infiltrating neutrophil is an independent prognostic factor in pancreatic ductal adenocarcinoma.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal malignancies. Tumor-infiltrating neutrophils (TINs) have been implicated in tumor progression and poor prognosis; however, their roles in PDAC remain unclear. TINs have been shown to granulocytic myeloid-derived suppressor cells (G-MDSCs) which inhibit adaptive immune responses and share morphological and functional features with classical neutrophils. G-MDSCs, unlike classical neutrophils, express myeloperoxidase (MPO). We evaluated the significance of TINs and MPO expression as a marker for prognosis in the PDAC. METHODS: We retrospectively analyzed 128 patients with surgically resected PDAC. The presence of TIN was assessed on hematoxylin and eosin-stained slides and immunohistochemistry was performed for MPO. RESULTS: TINs were identified in 61.7% of patients with PDAC. Their presence was significantly associated with worse overall survival and recurrence-free survival. After adjusting for clinicopathological variables, TIN remained an independent predictor of a poor prognosis. MPO was expressed in all TIN within PDAC, but was absent in neutrophils within benign inflammatory conditions. CONCLUSIONS: TIN in PDAC represents an independent adverse prognostic factor and is likely to be G-MDSCs based on MPO expression. Assessing TIN and MPO status in preoperative biopsy specimens may offer valuable prognostic information and guide future therapeutic strategies for PDAC.