Expression of Narcissus pseudonarcissus lectin and mannose receptor positive macrophages predict progression and prognosis of patients with gastric cancer

BACKGROUND: Mannose receptor (MR) is an immune adhesion molecule and is mainly expressed in macrophages and nonmature dendritic cells. The ligand mannose, one of the natural ligands of MR, is a monosaccharide, which is localized in the envelope or cytoplasm of macrophages. The aim of this study was to investigate expression of MR and its ligand mannose in tumor tissues of primary advanced gastric cancer and to evaluate the predictive and prognostic value of the positive cells in gastric cancer patients. METHODS: Histochemical staining for Narcissus pseudonarcissus lectin (NPL) and immunohistochemical envision two-step assay for MR were used to detect expression of NPL and MR in primary advanced gastric adenocarcinoma tissues. Adjacent non-cancerous gastric tissues of the patients were used as controls. Relationship of NPL and MR expression in the tumor tissues with clinicopathological features and survival time of the gastric cancer patients were analyzed. RESULTS: Numbers of NPL(+) and MR(+) macrophages in stromal tissues of gastric cancer were significantly higher than those in the adjacent non-cancerous gastric tissues (P=0.006; P<0.001). NPL expression in the primary tumor tissues was significantly more dominant than that in the adjacent non-cancerous gastric tissues (P=0.003). Expression of both the molecules in macrophages in tumor tissues was negatively correlated (r=−0.363, P=0.009). TNM stage of the patients was closely correlated to number of MR(+) macrophages and NPL expression in the stromal tissues of gastric cancer (P=0.009 and P=0.020). Kaplan-Meier survival model data showed that the patients with low counting of NPL(+) macrophages and high counting of MR(+) macrophages significantly led to worse disease progression and poorer prognosis (P=0.008). Cox regression analysis further demonstrated that high expression of MR(+) macrophages was an independent predictor of poor prognosis in patients with gastric cancer (P=0.033). CONCLUSIONS: Occurrence of mannose and MR in tumor tissues of gastric cancer might be prognostic factors for estimating risk of gastric cancer patients.