Fluorescence in situ hybridization improves the detection of 5q31 deletion in myelodysplastic syndromes without cytogenetic evidence of 5q

1 Laboratori de Citogenètica i Biologia Molecular, Laboratori de Citologia Hematològica. Servei de Patologia, IMAS. GRETNHE, IMIM-Hospital del Mar, Barcelona 2 Departament de Biologia Celular, Fisiologia i Immunologia. Facultat de Biociències. Universitat Autònoma de Barcelona, Bellaterra 3 Servicio de Hematología y IBMCC, Centro de Investigación del Cáncer, Universidad de Salamanca, Salamanca 4 Servicio de Genética, Laboratorio Gemolab, Madrid 5 Unidad de Genética. Hospital Universitario La Princesa, Madrid 6 Servicio de Hematología, Hospital Universitario La Fe, Valencia 7 Servicio de Hematología. Hospital Universitario Central de Asturias, Oviedo 8 Departamento de Genética. Universidad de Navarra, Pamplona 9 Servicio de Hematología y Hemoterapia. Hospital Arnau de Vilanova, Valencia 10 Servicio de Hematología. Consorcio Hospital General Universitario, Valencia 11 Servicio de Hematología. Hospital Universitario Marqués de Valdecilla, Santander 12 Servicio de Hematología. Hospital Sierrallana, Torrelavega 13 Servicio de Hematología. Hospital Universitario Dr Peset, Valencia 14 Servicio de Hematología, Hospital Universitario La Princesa, Madrid 15 Servicio de Genética. Hospital Universitario 12 de Octubre, Madrid 16 Servei d’Hematologia Clínica, IMAS. GRETNHE, IMIM-Hospital del Mar, Barcelona, Spain Correspondence: Dr. Francesc Solé, Laboratori de, Citogenètica i Biologia Molecular, Servei de Patologia, Hospital del Mar, Passeig Marítim 25-29, 08003 Barcelona. Spain. Phone: +34.93.2483521, Fax: +34.93.2483131, e-mail: fsole{at}imas.imim.es 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). Design and 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 si