Fluorescence in situ hybridization improves the detection of 5q31 deletion in myelodysplastic syndromes without cytogenetic evidence of 5q-.
BACKGROUND
More than 50% of patients with myelodysplastic syndromes present cytogenetic aberrations at diagnosis. Partial or complete deletion of the long arm of chromosome 5 is the most frequent abnormality. The aim of this study was to apply fluorescence in situ hybridization of 5q31 in patients diagnosed with de novo myelodysplastic syndromes in whom conventional banding cytogenetics study had shown a normal karyotype, absence of metaphases or an abnormal karyotype without evidence of del(5q).


METHODS
We performed fluorescence in situ hybridization of 5q31 in 716 patients, divided into two groups: group A patients (n=637) in whom the 5q deletion had not been detected at diagnosis by conventional banding cytogenetics and group B patients (n=79), in whom cytogenetic analysis had revealed the 5q deletion (positive control group).


RESULTS
In group A (n=637), the 5q deletion was detected by fluorescence in situ hybridization in 38 cases (5.96%). The majority of positive cases were diagnosed as having the 5q- syndrome. The deletion was mainly observed in cases in which the cytogenetics study had shown no metaphases or an aberrant karyotype with chromosome 5 involved. In group B (n=79), the 5q deletion had been observed by cytogenetics and was confirmed to be present in all cases by fluorescence in situ hybridization of 5q31.


CONCLUSIONS
Fluorescence in situ hybridization of 5q31 detected the 5q deletion in 6% of cases without clear evidence of del(5q) by conventional banding cytogenetics. We suggest that fluorescence in situ hybridization of 5q31 should be performed in cases of a suspected '5q- syndrome' and/or if the cytogenetic study shows no metaphases or an aberrant karyotype with chromosome 5 involved (no 5q- chromosome).
Mallo
Mar
M
Laboratori de, Citogenètica i Biologia Molecular, Servei de Patologia, IMAS, GRETNHE, IMIM-Hospital del Mar, Barcelona.
Arenillas
Leonor
L
Espinet
Blanca
B
Salido
Marta
M
Hernández
Jesús M
JM
Lumbreras
Eva
E
del Rey
Mónica
M
Arranz
Eva
E
Ramiro
Soraya
S
Font
Patricia
P
González
Olga
O
Renedo
Mónica
M
Cervera
José
J
Such
Esperanza
E
Sanz
Guillermo F
GF
Luño
Elisa
E
Sanzo
Carmen
C
González
Miriam
M
Calasanz
María José
MJ
Mayans
José
J
García-Ballesteros
Carlos
C
Amigo
Victoria
V
Collado
Rosa
R
Oliver
Isabel
I
Carbonell
Félix
F
Bureo
Encarna
E
Insunza
Andrés
A
Yañez
Lucrecia
L
Muruzabal
María José
MJ
Gómez-Beltrán
Elena
E
Andreu
Rafael
R
León
Pilar
P
Gómez
Valle
V
Sanz
Angeles
A
Casasola
Natalia
N
Moreno
Esperanza
E
Alegre
Adrián
A
Martín
María Luisa
ML
Pedro
Carmen
C
Serrano
Sergi
S
Florensa
Lourdes
L
Solé
Francesc
F
D016022:Case-Control Studies; D002869:Chromosome Aberrations; D002872:Chromosome Deletion; D002895:Chromosomes, Human, Pair 5 / Q000235:genetics*; D003582:Cytogenetics / Q000379:methods; D005260:Female; D017353:Gene Deletion; D006405:Hematology / Q000379:methods; D006801:Humans; D006824:Hybridization, Genetic; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008297:Male; D008677:Metaphase; D009190:Myelodysplastic Syndromes / Q000175:diagnosis / Q000235:genetics*