Unbalanced translocation t(5;17) in an typical acute promyelocytic leukemia.
Acute promyelocytic leukemia (APL; M3 in the FAB classification) is specifically associated with the t(15;17)(q23;q12) and the consequent formation of a PML/RARA fusion gene. A few cases of APL with a t(11;17)(q23;q12) and a PLZF/RARA fusion gene have recently been reported. In addition, a new variant, t(5;17)(q32;q12), with a RARA rearrangement was described in a child with atypical APL. We report an unbalanced der(5)t(5;17) in an atypical APL case showing unusual dysgranulopoiesis and some M2 features. The breakpoints were difficult to localize precisely on chromosome 5, because the translocation may have occurred on a previous del(5q). The karyotype also showed del(8q) and multiple double-minutes (dmin). Molecular studies evidenced RARA rearrangement but showed neither PML rearrangement nor PML/RARA fusion. Fluorescence in situ hybridization revealed that the dmin were of chromosome 8 origin and that they accounted for the MYC amplification observed in Southern blots. The patient did very poorly despite chemotherapy and all-trans retinoic acid (ATRA) treatment. Thus, the t(5;17) could represent a second type of variant translocation in APL that, like the disease associated with t(11;17), does not seem to respond to ATRA therapy. Whereas RARA rearrangement appears sufficient for an APL-like phenotype, it seems that the presence of a classical PML/RARA is required for typical APL with response to ATRA.
Brunel
V
V
Department of Biology, Institut Paoli-Calmettes, Marseille, France.
Sainty
D
D
Carbuccia
N
N
Arnoulet
C
C
Costello
R
R
Mozziconacci
M J
MJ
Simonetti
J
J
Coignet
L
L
Gabert
J
J
Stoppa
A M
AM
D000368:Aged; D002886:Chromosomes, Human, Pair 17; D002895:Chromosomes, Human, Pair 5; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D015473:Leukemia, Promyelocytic, Acute / Q000235:genetics*; D016133:Polymerase Chain Reaction; D014178:Translocation, Genetic