Expression of Epstein-Barr virus in carcinomas of major salivary glands: A strong association with lymphoepithelioma-like carcinoma

To elucidate the role of Epstein-Barr virus (EBV) in salivary gland carcinomas, 56 cases of carcinomas of major salivary glands were investigated. These included 14 mucoepidermoid carcinomas, 13 adenoid cystic carcinomas, seven malignant mixed tumors, four adenocarcinomas, four salivary duct carcinomas, two acinic cell carcinomas, two undifferentiated carcinomas without lymphoid stroma, seven lymphoepithelioma-like carcinomas (LELCs), two squamous cell carcinomas, and one small cell carcinoma. EBV transcripts were examined by in situ hybridization using digoxigenin-labeled oligonucleotide antisense probe for EBV-encoded RNA 1 (EBER1) on formalin-fixed paraffin- embedded tissue sections. EBER1 was detected in the malignant epithelial cells in all seven cases of LELC, but not in any of the other carcinomas and the neighboring normal salivary gland tissue. Because all the EBV-negative cases showed satisfactory labeling with the poly d(T) probe, the negative reaction with EBER1 was unlikely to be caused by poor RNA preservation in the tissues. The seven cases of LELC, which were histologically indistinguishable from undifferentiated nasopharyngeal carcinoma (NPC), had a disease-free 4- year survival rate of 85.7%. The results suggest that LELC of the salivary gland in Taiwanese Chinese may share similar EBV-related pathogenesis with that of NPC.