Presence of lytic Epstein‐Barr virus infection in nasopharyngeal carcinoma

• Published in: Head & neck 2018-07, Vol.40 (7), p.1515-1523
• Main Authors: Yu, Fenggang, Lu, Yanan, Petersson, Fredrik, Wang, De‐Yun, Loh, Kwok Seng
• Format: Article
• Language: English
• Subjects: BRLF1 gene; CD45 antigen; Cytokeratin; Epithelial cells; Epithelium; Epstein-Barr virus; Epstein‐Barr virus‐encoded RNA (EBER); Fibroblasts; Formaldehyde; Head and neck; Immunohistochemistry; Infections; Leukocytes; mRNA; Nasopharyngeal carcinoma; Nasopharynx; Nose; Paraffin; Phenotypes; RNA viruses; RNAscope in situ hybridization; Stroma; Throat cancer; Tumor cells; Tumors; Vimentin
• ISSN: 1043-3074; 1097-0347
• DOI: 10.1002/hed.25131

Background Chromogenic Epstein‐Barr virus‐encoded RNA (EBER) in situ hybridization (EBER‐ISH) is the gold standard to detect Epstein‐Barr virus (EBV) but it is difficult to use in conjunction with immunohistochemistry (IHC). In this study, our purpose was to validate the sensitivity and specificity of RNAscope in detection of EBV infection in nasal epithelium and its stroma. Methods Fluorescence‐based RNAscope EBER‐ISH, BRLF1‐ISH, and lineage marker‐IHC were performed on archived formalin‐fixed paraffin‐embedded tissues from normal nasal cavity (n = 5), nasopharynx (n = 8), and nasopharyngeal carcinoma (NPC) specimens (n = 10). Results The EBERs were detected in 10 of 10 NPC samples but was absent in all normal tissues from the nasal cavity and nasopharynx. The EBERs were exclusively located in pan‐cytokeratin (pan‐CK)‐positive tumor epithelial cells but not in CD45‐positive leukocytes and vimentin‐positive stromal fibroblasts. The level of EBER expression varied in tumor cells within patient and between patients as well. Additionally, 5 of 10 patients had positive BRLF‐ISH. Conclusion We developed a simple and reproducible method to simultaneously detect mRNA and protein in formalin‐fixed paraffin‐embedded tissues of NPC. As a single staining, traditional EBER continues to be useful; however, for interpretation of the phenotype of EBV‐infected cells, RNAscope is superior. Significantly, we showed that lytic EBV infection took place in NPC tumors.