Genotypic analysis of epstein‐barr virus isolates associated with nasopharyngeal carcinoma in chinese immigrants to the united states

EBV genotypes of first‐ and second‐generation Chinese diagnosed with nasopharyngeal carcinoma in the United States were analyzed by PCR techniques. Previous studies showed a geographical distribution of genotypically distinct sub‐types of EBV. Viruses detected at a higher frequency among Chinese NPC patients (Cf) were distinguished from those found in the majority of Caucasian NPC patients (DF) in the United States by polymorphisms in the BamHI F and I regions. Exploiting this distinction, we analyzed the biopsies of Chinese immigrants in the United States for their C/D and F/f genotypes to evaluate the importance of retention of the Cf virus among Chinese NPC patients in a geographical area where the DF virus prevails. This study shows that approximately 45.5 to 50% of first‐ and second‐generation Chinese NPC patients in California harbor the Cf virus, which is present in only 8% of Caucasian NPC patients in California. It is interesting that, while only 48% of the viral isolates from immigrant Chinese to California harbor the “f” variant, 96% harbor the type‐C viruses.