文章基本信息

标题：PD-L1 overexpression in EBV-positive gastric cancer is caused by unique genomic or epigenomic mechanisms
本地全文：下载
作者：Hiroshi Nakano ; Motonobu Saito ; Shotaro Nakajima 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2021
卷号：11
期号：1
页码：1982
DOI：10.1038/s41598-021-81667-w
出版社：Springer Nature
摘要：Abstract Epstein-Barr virus-positive gastric cancer [EBV ( ) GC] is a distinct GC subtype with unique genetic and epigenetic aberrations. Here, we examined resected GC samples and publicly available microarray data and The Cancer Genome Atlas (TCGA) database to identify the mechanism underlying overexpression of PD-L1 in EBV ( ) GC. We found that high levels of PD-L1 overexpression in EBV ( ) GC were caused by focal amplification of CD274 . By contrast, relatively high expression of PD-L1 in tumor tissue and infiltrating immune cells correlated with CD8 lymphocyte infiltration and IFN-γ expression via IRF3 activation. Since we reported previously that PD-L1 expression is associated both with the presence of CD8 T cells in the tumor microenvironment and with IFN-γ expression in GC, we examined a database to see whether IFN-γ-associated overexpression of PD-L1 plays a significant role in EBV ( ) GC. Immunohistochemical staining showed that expression of the IRF3 signature in clinical GC samples was higher in EBV ( ) than in EBV (−) cases. The data presented herein reveal a unique dual mechanism underlying PD-L1 overexpression in EBV ( ) GC: high focal amplification of CD274 or IFN-γ-mediated signaling via activation of IRF3.