Background: Epstein-Barr-virus-associated gastric carcinoma (EBVaGC) is a distinct subset of gastric carcinoma (GC). The expressions of cytokeratins (CK)7, 8, 18, 19 and 20 and truncated basic hair keratin 1 (hHb1-deltaN) were investigated in GC to clarify the characteristics of EBVaGC.
Materials and methods: For immunohistochemical evaluation, 173 GC tissues were examined and 31 GC tissues and 5 GC cell lines were used for quantitative real-time RT-PCR (qrt-RT-PCR) and RT-PCR.
Results: EBVaGC showed significantly lower immunohistochemical positivity of CK7 (-/(+/-)/+/+ +/+ + +; 27/15/4/1/1) compared to EBV-negative GC (12/29/27/44/13), even after stratification by histological types. The qrt-RT-PCR test demonstrated decreased amounts of CK7, 18 and 19 mRNAs in EBVaGC. Two among 5 GC cell lines showed a decrease of CK7 mRNA level after recombinant EBV infection. hHb1-deltaN expression was not specific to EBVaGC.
Conclusion: Abnormalities of CK7, 18 and 19 expressions, especially a decreased amount of CK7 expression, are characteristics of EBV-associated epithelial malignancies and might be important in carcinogenesis.