Epstein-Barr virus-enhancing plant promoters in east Africa.

: The extracts of a certain African plant species, Euphorbia tirucalli, were found to have markedly enhancing effects on the activation of latent Epstein-Barr virus (EBV) genomes in the EBV carrying lymphoblastoid cells and also on EBV-induced transformation of human lymphocytes. The Euphorbia tirucalli was especially noticeable in highly endemic areas of Burkitt's lymphoma (BL), an EBV-associated malignancy, in Kenya and Tanzania. The activation of the latent EBV genome and the EBV-induced transformation enhancement were also observed with the soil and drinking water taken around the plants, strongly indicating that the people living in BL endemic areas are frequently exposed to such an EBV-enhancing plant promoter substance.