Increased Expression of POSTN Predicts Poor Prognosis: a Potential Therapeutic Target for Gastric Cancer.

ABSTRACT

BACKGROUND: Periostin (POSTN) is involved in many biological processes and is associated with the occurrence and development of several cancers, while its role in gastric cancer is not clear. We aimed to demonstrate the relationship between POSTN and gastric cancer based on publicly available data from The Cancer Genome Atlas (TCGA) database. METHODS: POSTN expression data and corresponding clinical information were downloaded from TCGA database. We compared the expression of POSTN in gastric cancer samples and normal samples. POSTN-related differentially expressed genes (DEGs) were identified for further functional enrichment analysis. In addition, the relationships between POSTN expression and clinicopathological features and survival in patients with gastric cancer were also investigated through univariate and multivariate Cox regression analyses. Furthermore, a nomogram was constructed to predict the survival probability of gastric cancer patients. RESULTS: POSTN expression in gastric cancer was significantly higher than that in normal gastric tissues (p < 0.001). High POSTN expression in gastric cancer was significantly related to poor prognostic features, including greater tumor extent (odds ratio [OR] = 1.638 for T3 and T4 vs. T1 and T2), worse histological type (OR = 0.329 for diffuse type vs. tubular type), and advanced histological grade (OR = 1.646 for grade 3 vs. grades 1 and 2) (all p < 0.05). The 118 identified DEGs were primarily enriched in pathways related to tumorigenesis and tumor progression, including the TGF-ß signaling pathway, the WNT signaling pathway, and the signaling by VEGF. POSTN expression was positively correlated with the enrichment of the macrophages (r = 0.599, p < 0.001), helper T2 cells (r = 0.146, p = 0.005), and CD8 + T cells (r = 0.190, p < 0.001), but negatively correlated with the enrichment of Th17 cells (r = - 0.130, p = 0.012) and NK CD56bright cells. Kaplan-Meier survival analysis showed that high POSTN expression is associated with a short overall survival (hazard ratio [HR] = 1.54; p = 0.011). In the multivariate cox regression analysis, high POSTN expression was confirmed to be an independent predictor of poor overall survival (HR = 1.681; p = 0.017). The constructed nomogram can well predict the 1 and 3 years overall survival probability of patients with GC (0.696 [95% CI, 0.671-0.721]). CONCLUSION: POSTN plays an important role in the progression and prognosis of gastric cancer, and it may serve as a useful biomarker to predict survival in gastric cancer patients.