P. Talmant et al., CHILDHOOD B-CELL ACUTE LYMPHOBLASTIC-LEUKEMIA WITH FAB-L1 MORPHOLOGY AND A T(9-11) TRANSLOCATION INVOLVING THE MLL GENE, HEM CELL TH, 38(3), 1996, pp. 265-268
The t(9;11)(p21-22;q23) translocation is frequently associated with ac
ute monoblastic leukemia but may occasionally be seen in patients with
acute lymphoblastic leukemia (ALL). We report a case of childhood ALL
associated with t(9;11)(p21-22;q23) as the unique recurring chromosom
al abnormality. A 3-month-old girl presented with ''lymphomatous'' ALL
(renal enlargement), a high leukocyte count and central nervous syste
m (CNS) involvement. Leukemic cell typing revealed a sIg+ B-cell immun
ophenotype without CD10 and CD34 antigenic expression while the blast
cell morphology was of the FAB-L1 type. Splitting of a YAC encompassin
g the MLL gene was shown by fluorescence in situ hybridization (FISH)
studies of the patient's metaphase chromosomes. Rearrangement of the M
LL gene was confirmed by Southern blot analysis. Despite treatment wit
h an hyperintensive polychemotherapeutic regimen, the patient achieved
a complete remission but relapsed 9 months later. These results provi
de further evidence that the t(9;11) may be observed in ALL, involves
the MLL gene and is associated with a poor outcome. Moreover, this obs
ervation clearly illustrates that sIg+ B-cell ALL is not necessarily a
ssociated with a Burkitt (L3) morphology.