PROX1 Was Associated with LGR5 and Wnt Signaling and Contributed to Poor Prognosis in Gastric Cancer.

INTRODUCTION: We investigated whether the expression of prospero homeobox protein-1 (PROX1) in gastric cancer (GC) could be a prognostic marker. We also focused on the relationship between PROX1 and LGR5 and Wnt/ß-catenin activity in GC. METHODS: A total of 196 patients who underwent potentially curative surgery were collected and reviewed retrospectively. Immunohistochemistry was conducted and evaluated the expression PROX1, LGR5, Wnt3a, and ß-catenin expression. And we evaluated the relationship between PROX1 expression and clinicopathological features. RESULTS: The PROX1 low-expression group consisted of 105 patients (53.6%) and the high-expression group consisted of 91 patients (46.4%). For LGR5 expression, 76 patients (38.8%) were classified as low-expression, and 120 patients (61.2%) were classified as high-expression. The PROX1 low-expression group was significantly younger (p = 0.0095), had more intestinal type (p = 0.014), and had smaller tumor size (p = 0.013). The PROX1 high-expression group was significantly correlated with high LGR5 expression (p < 0.0001) and high Wnt3a expression (p = 0.012). In addition, there were significantly more cases of postoperative recurrence in the PROX1 high-expression group (p = 0.013). CONCLUSION: Our findings demonstrate that PROX1 correlated with the cancer stemness markers LGR5 and Wnt3a signaling in GC and had a poor prognosis including postoperative recurrence.