RESUMO
INTRODUCTION AND AIMS: In this retrospective study the authors studied how interphase fluorescence in situ hybridization can be applied to the diagnosis of numerical chromosomal anomalies failed to be identified by cytogenetic analysis. METHODS: Thirty-four patients, 27 with chronic granulocytic leukemia and seven with myelodysplastic syndrome, were studied in order to identify disease-specific aberrations, trisomy 8 and monosomy 7 using both traditional cytogenetic analysis and fluorescence in situ hybridization on interphase bone marrow cells. Using alphoid-satellite centromeric specific probes, trisomy 8 indicating the progression of the disease and poor prognosis in chronic granulocytic leukemia as well as monosomy 7 in myelodysplastic syndrome were identified. RESULTS: In 21 of 34 cases both methods led to the same results. In 13 patients fluorescence in situ hybridization making possible to examine a great number of cells, provided more information about the gain and loss of chromosomes above and clarified uncertain cytogenetic results. CONCLUSIONS: In both hematological malignancies, studied by the authors, fluorescence in situ hybridization proved a useful and sensitive method to determine chromosomes unrecognized or not accurately identified by the traditional cytogenetic analysis and to define the ratio of pathological cells. At the same time the results confirm that conventional cytogenetic analysis is still essential in diagnosing the genetic alterations of malignant cells and point at the chromosomes that are worth further studying by other methods.
