In vitro studies of B-cells immortalized by Epstein-Barr Virus (EBV) have shown that B-cell leukemia/lymphoma- 2 (bcl-2) protein expression is upregulated by the EBV-latency-associated antigen, latent membrane protein 1 (LMP1). The same phenomenon has also been observed in epithelial cells in vitro. However, such correlation between these 2 markers has not been shown in nasopharyngeal carcinoma (NPC), in which EBV infection is a well-known etiologic factor. This retrospective study examined 35 cases of undifferentiated NPC to answer the question of whether LMP1 and/or bcl-2 presence can be used as biomarkers at treatment response, as well as to see the relationship between bcl-2 and LMP in NPC. Of the 35 patients, 26 (74.3%) were bcl-2, and 10 (28.6%) were LMP1-positive. Although a significant correlation was observed between bcl-2 and LMP1 staining (P = .003), it appeared that bcl-2 expression could be independent of LMP1. Statistical analysis showed that cervical lymph node metastasis (P = .04) and cranial nerve involvement (P = .03) are the only variables that significantly affect patient survival. At this time, bcl-2 and LMP1 presence are not significant indicators of outcome; however, although they are not directly related to survival, expression of both bcl-2 and LMP1 was strongly correlated with cervical lymph node metastasis, which is a potent predictor of patient survival. Copyright (C) 2001 by W.B. Saunders Company.