Late-appearing PML/RARalpha fusion transcript with coincidental t(12;13)(p13.2;q14) in acute promyelocytic leukemia lacking the t(15;17) cytogenetic anomaly.
The late appearance of a cytogenetic/molecular hallmark in human leukemias is a rare event. We report on a case of acute myeloid leukemia with morphology, immunophenotype and clinical features typical of promyelocytic subtype (APL), in which the specific PML/RARalpha gene rearrangement was molecularly detected only at second relapse of disease, without cytogenetic evidence of the t(15;17). The emergence of the PML/RARalpha gene may be therapy-related or may represent the exceptional result of a clonal evolution during progression of neoplasia. At second relapse, a novel cell clone bearing a t(12;13)(p13.2;q14) was also observed and a molecular deletion and rearrangement of a locus at 13q14, distinct from retinoblastoma (Rb1) locus, was found. In this unusual case, the PML/RARalpha product seems to be not essential for the expression of the promyelocytic phenotype at diagnosis and, when detectable, it is not the sole genetic defect.
Temperani
P
P
Department of Medical Sciences, Section of Internal Medicine and Hematology, University of Modena, Modena, Italy.
Luppi
M
M
Giacobbi
F
F
Medici
V
V
Morselli
M
M
Barozzi
P
P
Marasca
R
R
Torelli
G
G
Emilia
G
G
D002881:Chromosomes, Human, Pair 12 / Q000648:ultrastructure*; D002882:Chromosomes, Human, Pair 13 / Q000648:ultrastructure*; D002884:Chromosomes, Human, Pair 15 / Q000648:ultrastructure; D002886:Chromosomes, Human, Pair 17 / Q000648:ultrastructure; D002999:Clone Cells / Q000473:pathology; D018450:Disease Progression; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000235:genetics* / Q000473:pathology; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000235:genetics*; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis*; D012334:RNA, Neoplasm / Q000096:biosynthesis*; D012008:Recurrence; D013997:Time Factors; D014178:Translocation, Genetic
D009363:Neoplasm Proteins; D015514:Oncogene Proteins, Fusion; D012333:RNA, Messenger; D012334:RNA, Neoplasm; C093476:promyelocytic leukemia-retinoic acid receptor alpha fusion oncoprotein