High frequency of trisomy 8 in acute promyelocytic leukemia: a fluorescence in situ hybridization study.
Correct diagnosis of acute promyelocytic leukemia (APL) requires proof of the translocation (15;17)(q24;q11), which appears to be absolutely specific for this particular type of myeloid disorder. We studied the karyotypes of 29 consecutive APL patients at diagnosis: in 5 of them banding techniques failed to detect the t(15;17). In these seemingly cytogenetically negative cases, fluorescence in situ hybridization (FISH) with a chromosome 17 painting probe detected a high percentage of mitoses with 3 hybridization signals: one derived from the intact chromosome 17, and 2 from the rearranged chromosomes 15 and 17. Trisomy 8 (+8) as a secondary chromosomal abnormality was observed in 8 cases (27.5%), confirming that the t(15;17) favors the acquisition of an extra chromosome 8. One of these 8 cases showed a marker that was interpreted by FISH analysis as der(8) with duplication of a segment of the long arm carrying the c-MYC allele. Clinical features of patients with t(15;17) and +8 were no different from patients with t(15;17) alone. The usefulness of FISH to standard banding techniques in the detection of specific structural and/or numerical chromosomal abnormalities is confirmed in this report.
Sessarego
M
M
Department of Internal Medicine, D.I.M.I., University of Genoa, Italy.
Fugazza
G
G
Balleari
E
E
Bruzzone
R
R
Ballestrero
A
A
Patrone
F
F
D000328:Adult; D002874:Chromosome Mapping; D002884:Chromosomes, Human, Pair 15; D002886:Chromosomes, Human, Pair 17; D002898:Chromosomes, Human, Pair 8; D016259:Genes, myc; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008875:Middle Aged; D014178:Translocation, Genetic; D014314:Trisomy