Promiscuous expression of Epstein-Barr virus genes in Burkitt's lymphoma from the central African country Malawi.

Primary BL in Malawian children has a very high frequency association, approaching 100%, with the human herpesvirus EBV. A detailed study carried out on viral gene expression in these tumours, using both fresh material and methanol-fixed FNAs, showed, contrary to prediction, that most belong to a variant "class II" latency category, with lytic cycle-related genes also expressed. That is, in addition to EBNA1 expression, membrane proteins (LMP1/2A), immediate early (BZLF1) and early (IR2 and IR4) genes, a putative viral oncogene (BARF1), CST (BART) antisense transcripts and the viral bcl-2 homologue are expressed in a high proportion of the BLs.