Our major goal is to understand the pathogenesis of undifferentiated lymphomas in terms of the environmental factors predisposing to these diseases and also the molecular changes responsible for neoplastic behaviour. We have focused predominantly on a comparison of Equitorial African and North American Burkitt's lymphoma. We have embarked upon an extensive characterization (immunologic and molecular genetics) of a series of cell lines derived predominantly from patients treated in the PB. We have focused particularly on the breakpoints related to the specific chromosomal translocations associated with these tumors, and the regulation of the c-myc gene, an oncogene adjacent to the breakpoint (or including the breakpoint) on chromosome 8. A number of systems have been established in which expression of either c-myc or the Ig gene is affected. These systems are used to gain information regarding the possibility that the c-myc gene is regulated by sequences present in the Ig locus, and brought into proximity with c-myc by virtue of the translocation.