Aims: Macrophage migration inhibitory factor (MIF) is implicated in tumorigenesis. This study was conducted to determine whether MIF expression is associated with gastric pathology and whether MIF expression is increased in malignant gastric cells in vitro. Materials and methods: Patients with a normal gastric mucosa, Helicobacter pylori infected gastritis, intestinal metaplasia, and gastric adenocarcinoma were included. Immunohistochemistry and enzyme linked immunosorbent assay (ELISA) were used to determine MIF expression in gastric epithelial cells and MIF levels in serum, respectively. Five gastric cancer cell lines (AGS, MKN-45, MKN-28, MGC-803, and SGC-7901) and one non-malignant gastric cell line (GES-1) were cultured for 24 hours. MIF protein in the supernatant and MIF mRNA in cultured cells were measured by ELISA and reverse transcriptionpolymerase chain reaction, respectively. Results: The percentage of MIF expressing epithelial cells was low in normal mucosa (12%) but substantially higher in gastritis (52%), intestinal metaplasia (66%), and gastric cancer (96%) (p,0.001, ANOVA). Serum MIF levels were low in patients with a normal mucosa (576 (82) pg/ml) but higher in patients with gastritis (2100 (349) pg/ml), intestinal metaplasia (4498 (253) pg/ml), and gastric cancer (9737 (1249) pg/ml) (p,0.001, ANOVA). There was a correlation between epithelial MIF expression and serum MIF levels (r = 0.776, p,0.001). In vitro, expression of MIF protein and mRNA was increased in malignant cells compared with non-malignant cells. Conclusions: Epithelial and serum MIF expression was progressively increased in H pylori induced gastritis, intestinal metaplasia, and gastric cancer, suggesting that MIF is involved in gastric carcinogenesis and may be a valuable biomarker for the early detection of gastric cancer.

Gastric cancer is the world's second most common malignancy and is a major threat to global health. IL-17, a CD4 T cell-derived mediator of angiogenesis, plays a major role in stimulating angiogenesis by regulating the production of a variety of proangiogenic factors, including the vascular endothelial growth factor (VEGF). The level of VEGF expression correlates with tumor progression and metastasis in gastric cancer tissues. Abnormal activation of signal transducer and activator of transcription 3 (Stat3) rendered the tumor cells highly angiogenic, which is manifested by an increased microvascular density (MVD) and considered it as a potential molecular marker for poor prognosis in gastric cancer angiogenesis. We determined that IL-17A-induced VEGF upregulation and neovascularization through a Stat3-mediated signaling pathway and hypothesized that blocking the Stat3 activation by using JSI-124, an inhibitor of phosphorylated Stat3, could significantly reduce the VEGF expression and can thus prevent angiogenesis. We showed an inhibition of angiogenesis and tumor progression when JSI-124 was treated with IL-17A in the cells and xenografts in an animal model and suggested that targeting the Stat pathway with JSI-124 could derive an effective therapeutic target for gastric cancers and could be a promising drug in gastric cancer treatment.