CD47 expression and CD163 + macrophages correlated with prognosis of pancreatic neuroendocrine tumor

Recent studies have suggested the important roles of CD47 and tumor-associated macrophages in the prognosis and immunotherapy of various human malignancies. However, the clinical significance of CD47 expression and CD163+ TAMs in pancreatic neuroendocrine tumor (PanNET) remains unclear. In this study, 47 well-differentiated PanNET resection specimens were collected. CD47 expression and CD163+ macrophages were evaluated using immunohistochemistry and correlated with clinicopathologic properties. Positive CD47 staining was seen in all PanNETs as well as adjacent normal islets. Compared to normal islets, CD47 overexpressed in PanNETs (p = 0.0015). In the cohort, lymph node metastasis (LNM), lymphovascular invasion (LVI), and perineural invasion (PNI) were found in 36.2, 59.6, and 48.9% of the cases, respectively. Interestingly, PanNETs with LNM, LVI, or PNI had significantly lower H-score of CD47 than those without LNM (p = 0.035), LVI (p = 0.0005), or PNI (p = 0.0035). PanNETs in patients with disease progression (recurrence/death) also showed a significantly lower expression of CD47 than those without progression (p = 0.022). In contrast, CD163+ macrophage counts were significantly higher in cases with LNM, LVI, and PNI. Our data suggest relative low CD47 expression and high CD163+ TAMs may act as indicators for poor prognosis of PanNETs.