The association between undifferentiated nasopharyngeal carcinoma and Epstein-Barr virus shown by correlated nucleic acid hybridization and histopathological studies.

All of 51 undifferentiated carcinomas of the nasopharynx were EBV-DNA-positive and, in the few tests performed, EBNA-positive as well. Most of these patients also had high anti-EBV [VCA and EA (D)] antibody titres. Of four patients that had somewhat differentiated NPCs, two were EBV-DNA-positive with a corresponding serological picture, whereas two were negative with an EBV serology comparable to that of healthy donors. Of seven lymphomas localized in the nasopharynx, one was EBV-DNA-positive and corresponded histologically to Burkitt's lymphoma, whereas six others were EBV-DNA-negative. Fourteen head and neck carcinomas outside the nasopharynx were all EBV-DNA-negative. These results confirm the consistent and unique association of EBV DNA with undifferentiated carcinomas of the nasopharynx.