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Differences in gastric carcinoma microenvironment stratify according to EBV infection intensity: implications for possible immune adjuvant therapy.

Strong MJ, Xu G, Coco J, Baribault C, Vinay DS, Lacey MR, Strong AL, Lehman TA, Seddon MB, Lin Z, Concha M, Baddoo M, Ferris M, Swan KF, Sullivan DE, Burow ME, Taylor CM, Flemington EK - PLoS Pathog. (2013)

Bottom Line: Epstein-Barr virus (EBV) is associated with roughly 10% of gastric carcinomas worldwide (EBVaGC).In four samples with the highest EBV coverage (hiEBVaGC - high EBV associated gastric carcinoma), transcripts from the BamHI A region comprised the majority of EBV reads.These results were confirmed in a separate cohort of 21 Vietnamese gastric carcinoma samples using qRT-PCR and on tissue samples using in situ hybridization and immunohistochemistry.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Tulane University, New Orleans, Louisiana, United States of America.

ABSTRACT
Epstein-Barr virus (EBV) is associated with roughly 10% of gastric carcinomas worldwide (EBVaGC). Although previous investigations provide a strong link between EBV and gastric carcinomas, these studies were performed using selected EBV gene probes. Using a cohort of gastric carcinoma RNA-seq data sets from The Cancer Genome Atlas (TCGA), we performed a quantitative and global assessment of EBV gene expression in gastric carcinomas and assessed EBV associated cellular pathway alterations. EBV transcripts were detected in 17% of samples but these samples varied significantly in EBV coverage depth. In four samples with the highest EBV coverage (hiEBVaGC - high EBV associated gastric carcinoma), transcripts from the BamHI A region comprised the majority of EBV reads. Expression of LMP2, and to a lesser extent, LMP1 were also observed as was evidence of abortive lytic replication. Analysis of cellular gene expression indicated significant immune cell infiltration and a predominant IFNG response in samples expressing high levels of EBV transcripts relative to samples expressing low or no EBV transcripts. Despite the apparent immune cell infiltration, high levels of the cytotoxic T-cell (CTL) and natural killer (NK) cell inhibitor, IDO1, was observed in the hiEBVaGCs samples suggesting an active tolerance inducing pathway in this subgroup. These results were confirmed in a separate cohort of 21 Vietnamese gastric carcinoma samples using qRT-PCR and on tissue samples using in situ hybridization and immunohistochemistry. Lastly, a panel of tumor suppressors and candidate oncogenes were expressed at lower levels in hiEBVaGC versus EBV-low and EBV-negative gastric cancers suggesting the direct regulation of tumor pathways by EBV.

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High levels of IDO1 in high EBV positive gastric carcinomas.(A) Gene expression profile of the cohort of 32 gastric carcinoma samples (12 EBV-positive and 20 EBV-negative). Both total EBV reads and IDO1 expression (RPKM-reads per kilobase of exon model per million mapped reads) are represented as red and blue columns, respectively. (B) Gene expression profile of the cohort of 21 Vietnamese gastric carcinomas and 5 normal adjacent samples. Both relative RPMS1 expression (-fold) and relative IDO1 expression (-fold) are represented as red and blue columns and are the fold difference compared to the average of normal adjacent control values. (C) Images of paraffin-embedded human gastric carcinoma probed for EBER using in situ hybridization or IDO1 staining with immunohistochemistry. F8 and A15 each represent a specific gastric carcinoma on the tissue array selected to be closely matched with respect to age, tumor grade and stage. Scale bar represents 50 µm.
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ppat-1003341-g009: High levels of IDO1 in high EBV positive gastric carcinomas.(A) Gene expression profile of the cohort of 32 gastric carcinoma samples (12 EBV-positive and 20 EBV-negative). Both total EBV reads and IDO1 expression (RPKM-reads per kilobase of exon model per million mapped reads) are represented as red and blue columns, respectively. (B) Gene expression profile of the cohort of 21 Vietnamese gastric carcinomas and 5 normal adjacent samples. Both relative RPMS1 expression (-fold) and relative IDO1 expression (-fold) are represented as red and blue columns and are the fold difference compared to the average of normal adjacent control values. (C) Images of paraffin-embedded human gastric carcinoma probed for EBER using in situ hybridization or IDO1 staining with immunohistochemistry. F8 and A15 each represent a specific gastric carcinoma on the tissue array selected to be closely matched with respect to age, tumor grade and stage. Scale bar represents 50 µm.

Mentions: The analysis of IDO1 levels for each of the 32 gastric carcinomas showed that the samples with the highest number of EBV reads had the highest levels of IDO1 expression (Figure 9A). To further explore the link between EBV and IDO1, we analyzed a separate cohort of Vietnamese gastric carcinoma samples by real time RT-PCR. RPMS1 was detected in two of these samples (CZRDPREA and WZQ1TALM) (Figure 9B) and these samples ranked among the highest for expression of IDO1 (27 and 17 fold relative to the average of the 5 normal adjacent tissue samples). Further, in these samples, normal adjacent tissue showed lower RPMS1 expression and lower IDO1 expression compared to their tumor counterparts. Notably, one of the EBV negative samples, W31AB410, showed the highest level of IDO1 (43 fold). Nevertheless, this sample was notable in that like the two EBV positive samples, the pathology report for this sample similarly noted high levels of immune cell infiltration which may result from the presence of another infectious agent.


Differences in gastric carcinoma microenvironment stratify according to EBV infection intensity: implications for possible immune adjuvant therapy.

Strong MJ, Xu G, Coco J, Baribault C, Vinay DS, Lacey MR, Strong AL, Lehman TA, Seddon MB, Lin Z, Concha M, Baddoo M, Ferris M, Swan KF, Sullivan DE, Burow ME, Taylor CM, Flemington EK - PLoS Pathog. (2013)

High levels of IDO1 in high EBV positive gastric carcinomas.(A) Gene expression profile of the cohort of 32 gastric carcinoma samples (12 EBV-positive and 20 EBV-negative). Both total EBV reads and IDO1 expression (RPKM-reads per kilobase of exon model per million mapped reads) are represented as red and blue columns, respectively. (B) Gene expression profile of the cohort of 21 Vietnamese gastric carcinomas and 5 normal adjacent samples. Both relative RPMS1 expression (-fold) and relative IDO1 expression (-fold) are represented as red and blue columns and are the fold difference compared to the average of normal adjacent control values. (C) Images of paraffin-embedded human gastric carcinoma probed for EBER using in situ hybridization or IDO1 staining with immunohistochemistry. F8 and A15 each represent a specific gastric carcinoma on the tissue array selected to be closely matched with respect to age, tumor grade and stage. Scale bar represents 50 µm.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3649992&req=5

ppat-1003341-g009: High levels of IDO1 in high EBV positive gastric carcinomas.(A) Gene expression profile of the cohort of 32 gastric carcinoma samples (12 EBV-positive and 20 EBV-negative). Both total EBV reads and IDO1 expression (RPKM-reads per kilobase of exon model per million mapped reads) are represented as red and blue columns, respectively. (B) Gene expression profile of the cohort of 21 Vietnamese gastric carcinomas and 5 normal adjacent samples. Both relative RPMS1 expression (-fold) and relative IDO1 expression (-fold) are represented as red and blue columns and are the fold difference compared to the average of normal adjacent control values. (C) Images of paraffin-embedded human gastric carcinoma probed for EBER using in situ hybridization or IDO1 staining with immunohistochemistry. F8 and A15 each represent a specific gastric carcinoma on the tissue array selected to be closely matched with respect to age, tumor grade and stage. Scale bar represents 50 µm.
Mentions: The analysis of IDO1 levels for each of the 32 gastric carcinomas showed that the samples with the highest number of EBV reads had the highest levels of IDO1 expression (Figure 9A). To further explore the link between EBV and IDO1, we analyzed a separate cohort of Vietnamese gastric carcinoma samples by real time RT-PCR. RPMS1 was detected in two of these samples (CZRDPREA and WZQ1TALM) (Figure 9B) and these samples ranked among the highest for expression of IDO1 (27 and 17 fold relative to the average of the 5 normal adjacent tissue samples). Further, in these samples, normal adjacent tissue showed lower RPMS1 expression and lower IDO1 expression compared to their tumor counterparts. Notably, one of the EBV negative samples, W31AB410, showed the highest level of IDO1 (43 fold). Nevertheless, this sample was notable in that like the two EBV positive samples, the pathology report for this sample similarly noted high levels of immune cell infiltration which may result from the presence of another infectious agent.

Bottom Line: Epstein-Barr virus (EBV) is associated with roughly 10% of gastric carcinomas worldwide (EBVaGC).In four samples with the highest EBV coverage (hiEBVaGC - high EBV associated gastric carcinoma), transcripts from the BamHI A region comprised the majority of EBV reads.These results were confirmed in a separate cohort of 21 Vietnamese gastric carcinoma samples using qRT-PCR and on tissue samples using in situ hybridization and immunohistochemistry.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Tulane University, New Orleans, Louisiana, United States of America.

ABSTRACT
Epstein-Barr virus (EBV) is associated with roughly 10% of gastric carcinomas worldwide (EBVaGC). Although previous investigations provide a strong link between EBV and gastric carcinomas, these studies were performed using selected EBV gene probes. Using a cohort of gastric carcinoma RNA-seq data sets from The Cancer Genome Atlas (TCGA), we performed a quantitative and global assessment of EBV gene expression in gastric carcinomas and assessed EBV associated cellular pathway alterations. EBV transcripts were detected in 17% of samples but these samples varied significantly in EBV coverage depth. In four samples with the highest EBV coverage (hiEBVaGC - high EBV associated gastric carcinoma), transcripts from the BamHI A region comprised the majority of EBV reads. Expression of LMP2, and to a lesser extent, LMP1 were also observed as was evidence of abortive lytic replication. Analysis of cellular gene expression indicated significant immune cell infiltration and a predominant IFNG response in samples expressing high levels of EBV transcripts relative to samples expressing low or no EBV transcripts. Despite the apparent immune cell infiltration, high levels of the cytotoxic T-cell (CTL) and natural killer (NK) cell inhibitor, IDO1, was observed in the hiEBVaGCs samples suggesting an active tolerance inducing pathway in this subgroup. These results were confirmed in a separate cohort of 21 Vietnamese gastric carcinoma samples using qRT-PCR and on tissue samples using in situ hybridization and immunohistochemistry. Lastly, a panel of tumor suppressors and candidate oncogenes were expressed at lower levels in hiEBVaGC versus EBV-low and EBV-negative gastric cancers suggesting the direct regulation of tumor pathways by EBV.

Show MeSH
Related in: MedlinePlus