Non-endemic Burkitt's lymphoma. A B-cell tumor related to germinal centers

To investigate the nature of non-endemic Burkitt's lymphoma, we examined neoplastic cells from eight American patients for receptors for sheep erythrocytes (E), complement (EAC), and Fc fragment of lgG (igGEA), and for surface immunoglobulins (Slg) and hydrolytic enzymes. In addition, we reviewed 47 biopsies and 17 autopsies from American patients to ascertain patterns of involvement by tumor in lymph nodes, spleens and Peyer's patches. Neoplastic cells in all cases studies bore monoclonal surface immunoglobulins of the igM class. Receptors for EAC and igGEA were identified on a minority of the cells. Little or no hydrolytic enzyme activity was demonstrable. These results indicate that, like Burkitt's lymphoma in Africans, this histologically identical tumor in American patients consists of B lymphocytes. In 10 biopsies and two autopsies, germinal centers were selectively involved by tumor, suggesting that these neoplastic cells may be related to some B lymphocytes of normal germinal centers.