Abstract

The quantity of nuclear DNA in 90 tumours with a strong probability of being associated with Epstein-Barr virus (EBV) (11 cases with nasopharyngeal carcinomas, seven cases of endemic and 26 of non-endemic Burkitt's lymphoma, and 46 cases of Hodgkin's disease) were analysed by flow cytometry. Twenty three cases with benign lymphadenopathies were analysed in a similar way. Except for endemic Burkitt's lymphoma most of the tumours were diploid. Near-diploid aneuploidy (with a DNA index ranging from 1.06 to 1.26) was also found in endemic Burkitt's lymphoma as well as in six non-endemic Burkitt's lymphomas and in eight cases of Hodgkin's disease but was absent in nasopharyngeal carcinomas. Tetraploid aneuploidy was seen in three cases of nasopharyngeal carcinoma. Five of the 23 cases of lymphadenopathy also showed near-diploid DNA, one of which subsequently developed into a non-Hodgkin's lymphoma. It is concluded that near-diploid DNA content seems to be associated with the lymphatic origins of the tumours rather than with EBV.