摘要目的:评估信号素5B(SEMA5B)在胃腺癌组织中的表达及其与患者预后的关系。方法:2019年11月通过TCGA数据库收集341例胃腺癌患者的临床病理特征和SEMA5B mRNA表达数据，分析胃腺癌组织中SEMA5B表达与患者临床病理特征和生存时间的关系。通过基因富集分析明确SEMA5B调控的相关信号通路。结果:341例胃腺癌组织中SEMA5B mRNA的表达量为0.577±0.587，癌旁正常组织中SEMA5B mRNA的表达量为0.132±0.075，差异有统计学意义( P<0.001)。SEMA5B mRNA高表达组(109例)患者的中位生存时间为14.5个月，明显低于SEMA5B mRNA低表达组(232例)患者(17.9个月， P＝0.047)。单因素分析结果显示，SEMA5B mRNA的表达与胃腺癌的组织学分级和T分期有关(均 P<0.05)。多因素Cox回归分析显示，患者的年龄和SEMA5B mRNA表达水平是胃腺癌患者预后的独立影响因素，年龄<65岁患者的死亡风险是≥65岁患者的1.042倍(95% CI为1.021～1.064)，SEMA5B mRNA高表达患者的死亡风险是低表达患者的1.195倍(95% CI为0.925～2.551)。基因富集分析显示，恶性肿瘤信号通路( P＝0.008)、MAPK信号通路( P＝0.047)和NOTCH信号通路( P＝0.029)在SEMA5B mRNA高表达组中均有不同程度的富集。 结论:SEMA5B可能是判断胃腺癌患者预后的潜在分子标志物。在胃腺癌组织中，恶性肿瘤信号通路、MAPK信号通路和NOTCH信号通路可能通过SEMA5B基因调控。

abstractsObjective:To evaluate the expression of semaphorin 5B (SEMA5B) in gastric adenocarcinoma and its relationship with prognosis.Methods:In November 2019, the clinicopathological characteristics and SEMA5B mRNA expression data of 341 patients with gastric adenocarcinoma were collected through TCGA database. The relationship between SEMA5B expression in gastric adenocarcinoma tissues and clinical pathologic features and overall survival were analyzed. Gene Set Enrichment Analysis (GSEA) was used to analyze the signaling pathways regulated by SEMA5B.Results:The expression level of SEMA5B mRNA in 341 gastric adenocarcinoma tissues was 0.577±0.587, in adjacent normal tissues was 0.132±0.075, the difference was statistically significant ( P<0.001). The median survival time of 109 patients with high expression of SEMA5B mRNA was 14.5 months, 232 patients with low expression of SEMA5B mRNA was 17.9 months ( P=0.047). Univariate analysis showed that the expression of SEMA5B mRNA was correlated with histological grade and T stage ( P<0.05). The multivariate analysis revealed that age<65 years remained independently associated with overall survival, with a hazard ratio( HR) of 1.042 (95% CI: 1.021-1.064). The multivariate analysis revealed that high expression of SEMA5b mRNA remained independently associated with overall survival, with a HR of 1.195 (95% CI: 0.925-2.551). GSEA showed that malignant tumor signaling pathways ( P=0.008), MAPK signaling pathways ( P=0.047) and Notch signaling pathways ( P=0.029) were differentially enriched in SEMA5B highly expressed phenotype. Conclusions:SEMA5B expression may be a potential prognostic molecular marker for prognosis of GAC patients. Moreover, malignant tumor signaling pathway, MAPK signaling pathway and Notch signaling pathway may be the key pathway regulated by SEMA5B in GAC.