Background: Transglutaminase 2 (TG2), a member of the transglutaminase family, also known as tissue transglutaminase, plays a fundamental role in cancer growth and progression. In this study, we aimed to comprehensively review the evidence of TG2 as a prognostic biomarker in solid tumors. Methods: PubMed, Embase, and Cochrane databases were searched for human studies with clearly described cancer types if they presented the relationship between TG2 expression and prognostic indicators from inception to February 2022. Two authors independently screened the eligible studies and extracted the relevant data. The association between TG2 and overall survival (OS), disease-free survival (DFS), and relapse-free survival (RFS) were described as hazard ratios (HR) and their corresponding 95% confidence intervals (CIs). Statistical heterogeneity was assessed using Cochrane Q-test and Higgins I-squared statistic. A sensitivity analysis was conducted by sequentially omitting the impact of each study. Publication bias was assessed by Egger's funnel plot. Results: A total of 2864 patients with various cancers from 11 individual studies were enrolled. Results showed that elevated TG2 protein expression and mRNA expression predicted a shorter OS, with a combined HR of 1.93 (95% CI: 1.41-2.63) or HR of 1.95 (95% CI: 1.27-2.99), respectively. Moreover, data suggested that elevated TG2 protein expression was correlated with a shorter DFS (HR = 1.76, 95% CI: 1.36-2.29); whereas elevated TG2 mRNA expression was associated with a shorter DFS (HR = 1.71, 95% CI: 1.30-2.24). Conclusions: Our meta-analysis indicated that TG2 might serve as a promising biomarker of cancer prognosis.

中文翻译：

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转谷氨酰胺酶 2 在实体瘤患者中的预后价值：一项荟萃分析。

背景：转谷氨酰胺酶 2 (TG2) 是转谷氨酰胺酶家族的一员，也称为组织转谷氨酰胺酶，在癌症的生长和进展中起着重要作用。在这项研究中，我们旨在全面审查 TG2 作为实体瘤预后生物标志物的证据。方法：在 PubMed、Embase 和 Cochrane 数据库中搜索明确描述癌症类型的人类研究，如果它们提供了从开始到 2022 年 2 月之间 TG2 表达与预后指标之间的关系。两位作者独立筛选符合条件的研究并提取相关数据。TG2 与总生存期 (OS)、无病生存期 (DFS) 和无复发生存期 (RFS) 之间的关联被描述为风险比 (HR) 及其相应的 95% 置信区间 (CI)。使用 Cochrane Q 检验和 Higgins I 平方统计评估统计异质性。通过依次忽略每项研究的影响进行敏感性分析。通过 Egger 的漏斗图评估发表偏倚。结果：共纳入来自 11 项研究的 2864 名患有各种癌症的患者。结果显示，升高的 TG2 蛋白表达和 mRNA 表达预示着较短的 OS，联合 HR 为 1.93（95% CI：1.41-2.63）或 HR 为 1.95（95% CI：1.27-2.99）。此外，数据表明，升高的 TG2 蛋白表达与较短的 DFS 相关（HR = 1.76，95% CI：1.36-2.29）；而升高的 TG2 mRNA 表达与较短的 DFS 相关（HR = 1.71，95% CI：1.30-2.24）。结论：