Absence of Epstein-Barr virus (EBV) in intrahepatic cholangiocarcinoma confirmed by lack of EBV-coded nuclear RNA and latent membrane protein-1

Lymphoepithelioma-like cholangiocarcinoma not associated with EBV

Reported herein is an unusual case of intrahepatic cholangiocarcinoma with lymphoepithelioma-like appearance in a 64-year-old man who was found to have an intrahepatic mass without cirrhosis. The tumor had two distinct histological patterns with dense lymphoplasmacytic infiltrate. The first was similar to nasopharyngeal undifferentiated carcinoma; the second pattern was a well-differentiated adenocarcinoma. Transition between the two components was observed in the same duct. Immunohistochemistry indicated that the tumor was immunoreactive with AE1/AE3 and cytokeratin (CK) 7, but negative for CEA and CK20. Stromal inflammatory infiltrate primarily consisted of plasma cells and lymphocytes. Immunohistochemical examination and in situ hybridization for EBV showed no integration of the virus in the tumor cells. Intrahepatic lymphoepithelioma-like carcinoma is rare, and most are associated with EBV. Only three cases were not associated with EBV. The authors would like to add one more example of the tumors not associated with EBV.

Vitamin E inhibits cyclosporin A and H2O2 promoted Epstein-Barr virus (EBV) transformation of human B cells as assayed by EBV oncogene LMP1 expression

BACKGROUND

We have previously shown that oxidative stress induced by H2O2 or cyclosporin A (CsA) can promote Epstein-Barr virus (EBV) transformation of human B cells as analyzed by colony formation, cell number, and by 3H-thymidine incorporation. In this report, we used EBV oncogene LMP1 as a marker to analyze H2O2 or CsA promotion of EBV transformation of human B cells and to test whether antioxidant vitamin E could inhibit H2O2 or CsA promoted LMP1 expression in the EBV-infected cells.

MATERIALS AND METHODS

Human splenocytes were prepared by centrifugation and plating technique to provide a greater than 80% pure preparation of B cells and were used for EBV infection. The EBV infected cells were treated with H2O2 (0.1 mM, 10 min), or with CsA (500 ng/ml) with or with out vitamin E (40 microM). The cells were cultured for up to 4 weeks. Samples were taken every week and were stained with phycoerythrin-conjugated mouse anti-LMP1 monoclonal antibody to assay LMP1 positive population by flow cytometry.

RESULTS

In EBV-infected cells, the LMP1-positive cell population reached 14% after 4 weeks of culture. CsA or H2O2 treatment promoted LMP1 positive population to 43% and 41% after 4 weeks of culture. Vitamin E (40 microM) completely inhibited LMP1 expression in EBV-infected cells and in CsA- or H2O2-treated cells.

CONCLUSION

In agreement with our previous observation, CsA or H2O2 can promote EBV transformation of human B cells. This oxidative stress induced promotion of EBV transformation can be blocked by antioxidant Vitamin E. This finding may have future therapeutic implications for post-transplant lymphoproliferative disorder.

Intrahepatic cholangiocarcinoma with lymphoepithelioma-like component

We present two cases of intrahepatic cholangiocarcinoma with lymphoepithelioma-like component. The patients included one woman and one man, aged 67 and 41 years, respectively. They presented with right upper quadrant pain and epigastralgia. Histologically, both tumors showed two distinct histological patterns with dense lymphoplasma cell infiltration. The first pattern was a well to moderately differentiated adenocarcinoma; the second component showed a feature similar to lymphoepithelioma-like carcinoma. Granulomatous reaction was noted in one case. Immunohistochemical study revealed that both tumors were immunoreactive with AE1/AE3, cytokeratin 7, and cytokeratin 19 but negative for carcinoembryonic antigen and cytokeratin 20. The stromal lymphocytes were composed of predominantly CD3(+) T cells. In situ hybridization for Epstein-Barr virus (EBV)-encoded RNA (EBER) showed positive nuclear signal in tumor cells but not in inflammatory cells in one case. The presence or absence of EBV genome was confirmed by polymerase chain reaction of LMP-1 gene in both cases. The LMP-1 gene also had a 30-bp deletion in Exon 3 as compared with the products from B95-8 cells. We further sequenced the PCR product and confirmed a 30-bp deletion between Nucleotide (nt) 168,282 and nt 168,253 corresponding to the B95-8 sequence. The clinical significance of 30-bp deletion in Exon 3 of the LMP-1 gene in lymphoepithelioma-like carcinoma of the liver warrants further investigation.

Lymphoepithelioma-like cholangiocarcinoma: an Epstein-Barr virus-associated tumor

Epstein-Barr virus (EBV) has been linked to carcinomas of several body sites, especially of the nasopharynx, salivary gland, lung, and stomach. We present five cases of lymphoepithelioma-like cholangiocarcinoma, including one that had been previously reported. Two patients were men and three were women. Their ages ranged from 42 to 66 years. Histologically, all five tumors were composed of variable proportions of undifferentiated epithelial cells and glandular components in a lymphocyte-rich stroma. EBV was detected in all five tumors by in situ hybridization for EBER-1 in both lymphoepithelioma-like carcinoma (LELC) and glandular parts, but not in 36 cases of cholangiocarcinoma without the LELC component. Taken together, these observations indicate that lymphoepithelioma-like cholangiocarcinoma is strongly linked to EBV. The LELC type of cholangiocarcinoma, like LELC of other body sites, may be more common in areas with endemic EBV infection.