[Pilot study of PML/RAR alpha fusion by fluorescence in situ hybridization (FISH)method in acute promyelocyte leukemia].
BACKGROUND
Acute promyelocytic leukemia (APL) is characterized cytogenetically by t(15;17) (q22;q21) and its molecular consequence, fusion of PML and RAR alpha genes. The detection of this genetic marker confirms the diagnosis and allows monitoring of the leukemic clone during treatment, which has prognostic value. Cytogenetics fails in some cases due to the absence of metaphases in cultures or their bad morphology. Southern blot and PCR methods require trained personnel and adequate equipment. FISH method allows the identification of chromosomic rearrangements in 24 to 48 h and is simple to set up in a cytogenetics laboratory.


OBJECTIVE
To evaluate the FISH method to detect PML/RAR alpha fusion, compared to cytogenetic analysis.


METHODS
Fifteen bone marrow specimens from APL patients with previous cytogenetic analysis were studied, using a commercial probe to detect PML/RAR alpha fusion.


RESULTS
We obtained a normal cut-off value of 9.1%. Specificity and sensibility were 100%. Six positive cytogenetic cases at diagnosis were FISH positive. Six negative cytogenetic cases, one APL at diagnosis and five normal controls were FISH negative. One case in remission, that was negative by cytogenetics, was positive near the cut-off value by FISH. Two other cases in remission, not conclusive by cytogenetics, were negative by FISH.


CONCLUSIONS
FISH is a reliable, rapid and relatively low cost method that can be used as an adjunct to conventional cytogenetics.
Legües
María Eugenia
ME
Laboratorio de Hematología, Departamento de Hematología-Oncología, Pontificia Universidad Católica de Chile, Lira 44, Santiago.
Franco
Giannina
G
Bertin
Pablo
P
D020732:Cytogenetic Analysis; D005819:Genetic Markers; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D015473:Leukemia, Promyelocytic, Acute / Q000175:diagnosis / Q000235:genetics*; D009363:Neoplasm Proteins / Q000032:analysis* / Q000235:genetics; D015514:Oncogene Proteins, Fusion / Q000032:analysis* / Q000235:genetics; D010865:Pilot Projects; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity
D005819:Genetic Markers; D009363:Neoplasm Proteins; D015514:Oncogene Proteins, Fusion; C093476:promyelocytic leukemia-retinoic acid receptor alpha fusion oncoprotein