Mature B-cell leukemias with more than 55% prolymphocytes: report of 2 cases with Burkitt lymphoma-type chromosomal translocations involving c-myc.
BACKGROUND
The molecular genetic events involved in the pathogenesis of mature B-cell leukemias with more than 55% prolymphocytes are not well characterized. We have encountered 2 such cases in which conventional cytogenetic analysis identified Burkitt lymphoma-type chromosomal translocations involving 8q24.


OBJECTIVE
To assess these 2 cases for involvement of the c-myc gene using fluorescence in situ hybridization analysis with probes specific for the c-myc and immunoglobulin heavy-chain (IgH) genes.


RESULTS
In both cases, conventional cytogenetic analysis demonstrated complex karyotypes, including chromosomal translocations involving 8q24. In case 1, a case of de novo prolymphocytic leukemia, the t(8;14)(q24;q32) was detected. In case 2, a case of chronic lymphocytic leukemia in prolymphocytoid transformation, the t(8;22)(q24;q11) was identified. Fluorescence in situ hybridization studies showed c-myc/IgH fusion signals in case 1, proving the presence of the t(8;14). Split c-myc signals without fusion to IgH were observed in case 2, proving c-myc gene rearrangement and consistent with the t(8;22).


CONCLUSIONS
These results suggest that c-myc gene alterations may be involved in the pathogenesis of a subset of mature B-cell leukemias with more than 55% prolymphocytes.
Merchant
Shakil
S
Division of Pathology and Laboratory Medicine, The University of Texas M. D. Anderson Cancer Center, Houston 77030, USA.
Schlette
Ellen
E
Sanger
Warren
W
Lai
Raymond
R
Medeiros
L Jeffrey
LJ
D000368:Aged; D002051:Burkitt Lymphoma / Q000235:genetics*; D002883:Chromosomes, Human, Pair 14 / Q000235:genetics; D002898:Chromosomes, Human, Pair 8 / Q000235:genetics; D005260:Female; D016259:Genes, myc / Q000235:genetics; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D015448:Leukemia, B-Cell / Q000175:diagnosis* / Q000235:genetics*; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000175:diagnosis / Q000235:genetics; D015463:Leukemia, Prolymphocytic / Q000175:diagnosis* / Q000235:genetics*; D007953:Leukemia, Radiation-Induced / Q000175:diagnosis / Q000235:genetics; D008297:Male; D015514:Oncogene Proteins, Fusion / Q000235:genetics; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics*; D014178:Translocation, Genetic / Q000235:genetics*
D007143:Immunoglobulin Heavy Chains; D015514:Oncogene Proteins, Fusion; D016271:Proto-Oncogene Proteins c-myc