目的 ·研究 β-内酰胺酶（ lactamase β，LACTB）在胃癌中的表达及其对胃癌患者预后的影响。方法 ·用免疫组织化学法分析 LACTB在 90对配对的胃癌及癌旁组织中的表达差异。用 Kaplan-Meier Plotter数据库分析胃癌组织中 LACTB mRNA的表达变化与胃癌预后的关系。 Cox模型分析影响胃癌患者总生存期的因素并建立预后预测列线图模型。用 STRING数据库分析与 LACTB相互作用的蛋白，并对 LACTB及其相互作用蛋白标以显著关联的 GO（gene ontology）功能类标签和 KEGG（Kyoto encyclopedia of genes and genomes）通路。结果 · LACTB在胃癌组织中的表达显著低于癌旁组织（P0.000）。LACTB mRNA低表达预示胃癌患者不良预后，预后预测列线图的一致系数为 0.641；LACTB及与其相互作用的 38种蛋白参与了 5条信号通路， GO注释分类结果表明富集于 1类细胞学组分、9类分子功能和 2类生物学过程。结论 ·在胃癌中 LACTB低表达是一种不良预后因素。

Objective · To investigate the level of lactamase β (LACTB) in gastric cancer and its influence on the prognosis of gastric cancer patients. Methods · The varied of LACTB in 90 pairs of gastric cancer tissue and peritumor tissue was analyzedimmunohistochemistry. The prognostic role of LACTB mRNA in gastric cancer was analyzedthe Kaplan-Meier Plotter database. The factors affecting the overall survival of gastric cancer patients were analyzed with Cox survival model. The prognostic nomogram model was established to predict overall survival of gastric cancer patients. The proteins which interacted with LACTB were analyzedthe STRING database, and they were taggedthe noassociated functional cluster of GO (gene ontology) and KEGG (Kyoto encyclopedia of genes and genomes) pathway. Results · The of LACTB in gastric cancer tissue was obviously lower than that in peritumor tissue (P0.000). The low of LACTB mRNA may suggest that the prognosis of gastric cancer patient is poor, and the C-index of nomogram for predicting prognosis of gastric cancer patients was 0.641. A set of LACTB and 38 proteins which interacted with LACTB participated in five kinds of signaling pathway. Results for the classification of GO (gene ontology) annotation demonstrated that the proteins were involved in one kind of cellular component, nine kinds of molecular function and two kinds of biological process. Conclusion · The low of LACTB may be a poor-prognostic factor in gastric cancer.