2 CASES OF MATURE B-CELL ACUTE LYMPHOCYTIC-LEUKEMIA WITH NORMAL KARYOTYPE IN ADULTS

Acute lymphocytic leukemia with mature B-cell phenotype (B-ALL) is a r are type of ALL. Although B-ALL cells commonly have a characteristic c hromosomal translocation that includes 8q24 (the location of the c-myc protooncogene), the leukemic cells of the two patients reported in th is paper showed normal karyotypes. This finding was confirmed by South ern blot analysis of bone marrow cells in case 1. A c-myc probe was us ed, and no rearrangement or amplification of c-myc expression was foun d; B-ALL with the translocation including 8q24 is reported to show hig h levels of expression of rearranged c-myc. Investigation of anti-Epst ein-Barr virus (EBV) antibody revealed that both cases 1 and 2 had a p ast history of EBV infection. However, at least in case 1, integration of the EBV genomic DNA into the leukemic cells was not detected by th e polymerase chain reaction in which specific primers for EBV were emp loyed. The difference in pathophysiology between B-ALL with and withou t the 8q24 translocation is unclear; however, the prognosis of the two patients with B-ALL with the normal karyotype was as poor as that of B-ALL with the chromosomal translocation.