Lymphoepithelial carcinoma of the salivary gland: in situ detection of Epstein-Barr virus.

AIM To examine the role of Epstein-Barr virus (EBV) in lymphoepithelial carcinoma of the salivary gland in Hong Kong Chinese. METHODS Ten cases of lymphoepithelial carcinoma of the salivary gland (eight parotid and two submandibular) were examined. In situ hybridisation was used to localise EBER RNA, immunohistochemical methods to detect expression of latent membrane protein 1 (LMP-1) in EBV positive tumours, and Southern blot analysis to examine the clonality of EBV in the two cases where frozen tissue was available. RESULTS None of the cases had a history of Sjögren's syndrome or histological evidence of a benign lymphoepithelial lesion. The IgA antibody titre against EBV viral capsid antigen was elevated in four cases. All cases were EBV positive by in situ hybridisation, with a strong uniform positive signal in the epithelial cells, and all cases expressed LMP-1. Southern blot analysis revealed that the clonal episomal form of the virus was present. Two of the three female patients in this series also developed carcinoma of cervix. One of these carcinomas had histological features of a lymphoepithelioma-like carcinoma but was EBV negative. CONCLUSIONS A consistent association between EBV and lymphoepithelial carcinoma of the salivary gland was found. The presence of the virus in a clonal episomal form, and the expression of LMP-1 viral oncoprotein is further evidence of the role of EBV in the oncogenesis of this tumour.