背景 与目的胃癌是我国常见的致死性胃肠道恶性肿瘤之一.RSAD2(radical SAM domain-containing 2,RSAD2)与胃癌的发生发展、诊断治疗及预后的相关性尚未见报道,本文旨在探讨RSAD2在胃癌患者中的表达情况,并阐明其对预后的影响.方法 采用实时定量逆转录聚合酶链式反应(reverse transcription polymerase chain reaction,RT-PCR)对17例胃癌及配对的癌旁正常组织中RSAD2的mRNA表达水平进行检测;采用蛋白质免疫印迹对5例胃癌及配对的癌旁正常组织中RSAD2的蛋白水平进行检测;采用免疫组织化学法(immunohistochemistry,IHC)对386例胃癌及配对的癌旁正常组织中RSAD2的蛋白表达水平进行检测;通过卡方检验分析RSAD2表达与不同临床因素之间的相关性,Kaplan-Meier法绘制生存曲线,log-rank检验比较生存曲线之间的差异,Cox比例风险回归模型分析预后因素.结果 胃癌组织中RSAD2的mRNA和蛋白表达水平高于配对的癌旁正常组织.IHC检测结果显示,RSDA2在胃癌组织中的表达明显高于配对的癌旁正常组织,其表达定位于癌细胞的细胞质;而且,RSAD2高表达与患者的年龄(P=0.011)和TNM分期(P=0.040)相关;RSAD2高表达患者的总生存(P=0.003)和无进展生存(P=0.019)时间显著短于低表达患者.多因素分析显示,RSAD2表达水平可作为胃癌患者的独立预后因素[风险比(HR,hazard ratio)=1.358,95％置信区间(CI,confidence interval):1.001-1.844;P=0.049)].随后在胃癌细胞AGS和HGC27中敲低RSAD2的表达后会抑制胃癌细胞的增殖和克隆形成能力.结论 RSAD2在胃癌组织中高表达,可作为潜在的胃癌预后生物标志物.

Background Epstein-Barr virus (EBV)-associated gastric carcinomas (EBVaGCs) present unique molecular signatures, but the tumorigenesis of EBVaGCs and the role EBV plays during this process remain poorly understood. Methods We applied whole-exome sequencing, EBV genome sequencing, and whole-genome bisulfite sequencing to multiple samples ( n = 123) derived from the same patients ( n = 25), which covered saliva samples and different histological stages from morphologically normal epithelial tissues to dysplasia and EBVaGCs. We compared the genomic landscape between EBVaGCs and their precursor lesions and traced the clonal evolution for each patient. We also analyzed genome sequences of EBV from samples of different histological types. Finally, the key molecular events promoting the tumor evolution were demonstrated by MTT, IC50, and colony formation assay in vitro experiments and in vivo xenograft experiments. Results Our analysis revealed increasing mutational burden and EBV load from normal tissues and low-grade dysplasia (LD) to high-grade dysplasia (HD) and EBVaGCs, and oncogenic amplifications occurred late in EBVaGCs. Interestingly, within each patient, EBVaGCs and HDs were monoclonal and harbored single-strain-originated EBV, but saliva or normal tissues/LDs had different EBV strains from that in EBVaGCs. Compared with precursor lesions, tumor cells showed incremental methylation in promotor regions, whereas EBV presented consistent hypermethylation. Dominant alterations targeting the PI3K-Akt and Wnt pathways were found in EBV-infected cells. The combinational inhibition of these two pathways in EBV-positive tumor cells confirmed their synergistic function. Conclusions We portrayed the (epi) genomic evolution process of EBVaGCs, revealed the extensive genomic diversity of EBV between tumors and normal tissue sites, and demonstrated the synergistic activation of the PI3K and Wnt pathways in EBVaGCs, offering a new potential treatment strategy for this disease.

Bmi1 is overexpressed in multiple human cancers. We previously reported the oncogenic function and the transcription regulation mechanisms of Bmi1 in nasopharyngeal carcinoma (NPC). In this study, we observed that the mRNA and the protein levels of Bmi1 were strictly inconsistent in NPC cell lines and cancer tissues. The inhibitors of proteasome and lysosome could not enhance the protein level of Bmi1, indicating that Bmi1 may be post-transcriptionally regulated. The IRESite analysis showed that there were two potential internal ribosome entry sites (IRESs) in the 5 '-untranslated region (5 '-UTR) of Bmi1. The luciferase assay demonstrated that the 5 '-UTR of Bmi1 has IRES activity, which may mediate cap-independent translation. The IRES activity of the Bmi1 5 '-UTR was significantly reduced after the mutation of the two IRES elements. Taken together, these results suggested that the IRES elements mediating translation is a novel post-transcriptional regulation mechanism of Bmi1.

Esophageal squamous cell carcinoma (ESCC) is a malignant epithelial tumor with a high incidence in East Asia and the Middle East. The outcomes for ESCC patients are usually not optimal due to the recurrence and metastasis. This study is aim to examine the expression and the prognostic value of LAG-3 in ESCC. We applied immunohistochemistry analysis to examine the expression of LAG-3, CD4 and CD8 in 287 ESCC cohorts. Our study demonstrated that the decreased LAG-3 expression was significantly associated with CD4 tumor-infiltrated lymphocytes (TILs) (p=0.000), CD8 TILs (p=0.000), and the advanced clinical stages (p=0.041) by Chi-square analysis. Kaplan-Meier survival analysis revealed that higher LAG-3 expression were positively correlated with a better overall survival (OS) (p=0.010) and better progression free survival (PFS) (p=0.006), especially in the patients at stages T1-2 status (p=0.001, OS; p=0.001, PFS), N0 status (p=0.036, OS; p=0.050, PFS), and early stages (I-II) (p=0.006, OS; p=0.008, PFS). Both high of CD4 TIL /CD8 TIL ratio and LAG-3 expression were correlated with longer OS and PFS. Cox proportional hazards regression analysis showed that LAG-3 is an independent biomarker of survival (HR, 0.724; 95% CI 0.526-0.995; p = 0.047) (p=0.036). Taken together, we found that high expression of LAG-3 was correlated with an improved survival and LAG-3 is an independent predictor of survival, suggesting that LAG-3 may serve as a useful immune marker for the prognosis of ESCC.