Department of Pathology, Centro Hospitalar de São João, Al. Prof. Hernâni Monteiro, 4200-319, Porto, Portugal.
Department of Pathology, Faculty of Medicine of the University of Porto (FMUP), Al. Prof. Hernâni Monteiro, 4200-319, Porto, Portugal.
Gastric Cancer. 2019 Jan;22(1):77-90. doi: 10.1007/s10120-018-0836-8. Epub 2018 May 19.
Gastric cancer with lymphoid stroma (GCLS) is characterized by prominent stromal infiltration of T-lymphocytes. The aim of this study was to investigate GCLS biology through analysis of clinicopathological features, EBV infection, microsatellite instability (MSI), immune gene-expression profiling and PD-L1 status in neoplastic cells and tumor immune microenvironment.
Twenty-four GCLSs were analyzed by RNA in situ hybridization for EBV (EBER), PCR/fragment analysis for MSI, immunohistochemistry (PD-L1, cytokeratin, CD3, CD8), co-immunofluorescence (CK/PD-L1, CD68/PD-L1), NanoString gene-expression assay for immune-related genes and PD-L1 copy number alterations. CD3+ and CD8+ T-cell densities were calculated by digital analysis. Fifty-four non-GCLSs were used as control group.
GCLSs displayed distinctive clinicopathological features, such as lower pTNM stage (p = 0.02) and better overall survival (p = 0.01). EBV+ or MSI-high phenotype was found in 66.7 and 16.7% cases, respectively. GCLSs harbored a cytotoxic T-cell-inflamed profile, particularly at the invasive front of tumors (p < 0.01) and in EBV+ cases (p = 0.01). EBV+ GCLSs, when compared to EBV- GCLSs, showed higher mRNA expression of genes related to Th1/cytotoxic and immunosuppressive biomarkers. PD-L1 protein expression, observed in neoplastic and immune stromal cells (33.3 and 91.7%, respectively), and PD-L1 amplification (18.8%) were restricted to EBV+/MSI-high tumors and correlated with high values of PD-L1 mRNA expression.
This study shows that GCLS has a distinctive clinico-pathological and molecular profile. Furthermore, through an in-depth study of tumor immune microenvironment-by digital analysis and mRNA expression profiling-it highlights the role of EBV infection in promoting an inflamed tumor microenvironment, with putative therapeutic implications.
富含淋巴细胞的胃癌（GCLS）的特征是 T 淋巴细胞显著浸润间质。本研究旨在通过分析临床病理特征、EBV 感染、微卫星不稳定性（MSI）、免疫基因表达谱以及肿瘤细胞和肿瘤免疫微环境中 PD-L1 状态，来研究 GCLS 生物学。
通过 RNA 原位杂交分析 24 例 GCLS 的 EBV（EBER），PCR/片段分析 MSI，免疫组化（PD-L1、细胞角蛋白、CD3、CD8），共免疫荧光（CK/PD-L1、CD68/PD-L1），NanoString 免疫相关基因表达谱和 PD-L1 拷贝数改变，用数字分析计算 CD3+和 CD8+T 细胞密度。54 例非 GCLS 作为对照组。
GCLS 表现出独特的临床病理特征，如较低的 pTNM 分期（p=0.02）和较好的总生存（p=0.01）。EBV+或 MSI-高表型分别占 66.7%和 16.7%。GCLS 具有细胞毒性 T 细胞浸润的特征，特别是在肿瘤的浸润前缘（p<0.01）和 EBV+病例中（p=0.01）。与 EBV-GCLS 相比，EBV+GCLS 中与 Th1/细胞毒性和免疫抑制生物标志物相关的基因表达更高。肿瘤细胞和免疫间质细胞中观察到 PD-L1 蛋白表达（分别为 33.3%和 91.7%）和 PD-L1 扩增（18.8%）仅限于 EBV+/MSI-高肿瘤，与 PD-L1 mRNA 表达的高值相关。
本研究表明 GCLS 具有独特的临床病理和分子特征。此外，通过对肿瘤免疫微环境的深入研究——通过数字分析和 mRNA 表达谱——它强调了 EBV 感染在促进炎症肿瘤微环境中的作用，具有潜在的治疗意义。
