The latent membrane protein-1 (LMP1) of Epstein-Barr virus (EBV) is a viral oncoprotein implicated in several EBV-associated pathologies. Many studies have characterized carboxy-terminal mutations within LMP1, errors in this area are critical since this portion contains sequences responsible for LMP1 targeting, half-life and association with host cell proteins. Although, data suggests that mutations in this area extend LMP1 half-life and increase its oncogenesis, some studies have not shown this to be true for all EBV-associated tumors. In order to evaluate 3'-end LMP1-DNA mutations in three different ethnic populations with nasopharyngeal carcinoma (NPC), we examined EBV-DNA in 34 patients of various origins (Caucasian, Chinese and Inuit). While 68% of the total group expressed EBV-antigens, only 56% of Caucasians but 86% of Inuit expressed this viral protein. Over 67% of Inuit NPC tissue contained the characteristic 30 bp deletion that was observed in only 20% of Caucasians and 33% of Chinese samples. DNA sequencing revealed that the Inuit population showed the most frequent DNA mutations and corresponding amino acid alterations in LMP1. Our results suggest that EBV-associated NPC-DNA mutations in LMP1 do not occur at equal rates in different racial groups and are more common at distinct sites in NPC tissue from Chinese and Inuit sources.