Supplementary Material for: High MT2A Expression Predicts Worse Prognosis in Patients with Urothelial Carcinoma

Introduction: Dysregulation of metal ion homeostasis is associated with urothelial carcinogenesis. From a published urinary bladder urothelial carcinoma (UBUC) transcriptome, we identified metallothionein 2A (MT2A) as the most significantly upregulated gene implicated in cancer progression among metal ion binding-related genes. Therefore, we analyzed the association between MT2A expression and clinical significance in our well-characterized cohort of patients with upper tract urothelial carcinoma (UTUC) and UBUC.
Methods: We retrospectively reviewed the clinicopathological characteristics of 295 and 340 patients with UBUC and UTUC, respectively. MT2A expression was assessed using real-time reverse transcriptase-polymerase chain reaction and immunohistochemistry. We further correlated MT2A expression with clinicopathological factors, disease specific survival (DSS) and metastasis-free survival (MFS) using the Pearson's chi-square test, Kaplan-Meier analysis, and multivariate Cox proportional hazards model.
Results: High MT2A expression was significantly associated with aggressive pathological features including high tumor stage, lymph node metastasis, high tumor grade, vascular invasion, and perineural invasion. In the Kaplan-Meier analysis, high MT2A expression was significantly correlated with poor DSS (P < 0.0001) and MFS (P < 0.0001); in the multivariate analysis, it was an independent predictor of CSS (P < 0.001) and MFS (P = 0.001). Gene co-expression analysis demonstrated that MT2A overexpression promotes UC progression through complement activation.
Conclusion: High MT2A expression correlated with aggressive UC features and was an independent predictor of cancer metastasis and patient survival, suggesting its role in risk stratification and decision-making in patients with UTUC and UBUC.

引言：金属离子稳态失调与尿路上皮癌变密切相关。我们从已发表的膀胱尿路上皮癌（UBUC）转录组数据中，鉴定出金属硫蛋白2A（MT2A）是金属离子结合相关基因中与癌症进展关联最显著的上调基因。因此，我们在特征明确的上尿路尿路上皮癌（UTUC）和膀胱尿路上皮癌患者队列中，分析了MT2A表达与临床意义之间的关联。
方法：我们回顾性分析了295例膀胱尿路上皮癌患者及340例上尿路尿路上皮癌患者的临床病理特征。采用实时逆转录聚合酶链反应和免疫组织化学方法检测MT2A的表达水平。进一步通过Pearson卡方检验、Kaplan-Meier分析及多因素Cox比例风险模型，将MT2A表达与临床病理因素、疾病特异性生存（DSS）及无转移生存（MFS）进行相关性分析。
结果：MT2A高表达与多种侵袭性病理特征显著相关，包括高肿瘤分期、淋巴结转移、高肿瘤分级、血管侵犯及神经周围侵犯。Kaplan-Meier分析显示，MT2A高表达与较差的疾病特异性生存（P < 0.0001）和无转移生存（P < 0.0001）显著相关；多因素分析表明，MT2A高表达是疾病特异性生存（P < 0.001）及无转移生存（P = 0.001）的独立预测因子。基因共表达分析显示，MT2A过表达通过补体激活促进尿路上皮癌进展。
结论：MT2A高表达与尿路上皮癌的侵袭性特征相关，且是癌症转移及患者生存的独立预测因子，提示其可用于上尿路尿路上皮癌和膀胱尿路上皮癌患者的风险分层及临床决策制定。