Geographic variation in t(8;14) chromosomal breakpoint locations and EBV association in Burkitt's lymphoma

We have extended our analysis of the geographical variation in the pattern of t(8; 14) chromosomal breakpoint locations and EBV association in Burkitt 's lymphoma and conducted a more detailed analysis of the geography of the molecular subtypes of BL based on 120 tumors. Our data, overall, suggest th at chromosomal breakpoint locations on chromosome 8 fall into three main gr oups, and that each of these groups is variably represented in the countrie s studied so far. In Equatorial Africa (Ghana) and Brazil, the predominant breakpoint location is outside the HindIII fragment encompassing c-myc (74% and 50% respectively). In temperate South American tumors (from Argentina and Chile) breakpoints most often (48%) occur in the c-myc regulatory regio n immediately upstream of the major promoters, P1 and P2. In tumors from th e USA and North Africa (Algeria), most breakpoints are downstream of the ma jor promoters and result in truncation of c-myc (60% and 43% respectively). Ghanaian and North American tumors differ most dramatically from each othe r. Most breakpoints in Ghanaian tumors are outside HindIII (74%), while mos t of those in North American tumors are within HindIII (91%). EBV associati on also differs, being highest in Ghanaian and Algerian tumors (both 100%) lowest in US tumors (38%) and intermediate in South American countries. Our results suggest that environmental factors or lifestyle influence the mole cular subtype, in Burkitt's lymphoma, but do not support a relationship bet ween the presence of EBV and breakpoint locations - at least, as determined by Southern blotting.