Evidence for viruses in acute leukemia and Burkitt's tumor

On the basis of experience with oncogenic animal viruses it is likely that at least some human malignancies are virus-induced. The problems to be faced in assigning an oncogenic potential to a human virus have been discussed and illustrated by observations made on the herpes-type virus which frequently is associated with cultured cells of the hematopoietic system. This virus seems to fulfill some of the criteria established for transformation of normal cells by oncogenic animal viruses yet the present information is insufficient to prove an etiologic relationship of the herpes-type virus to Burkitt's lymphoma or other tumors of the hematopoietic system.