[Use of a chromosome 21 gene library in the identification of a marker chromosome in chronic myeloid leukemia].

The non-isotopic in situ hybridization makes it possible the analysis of, both, numeric and structural chromosome aberrations in interphase nuclei. Moreover, this technique is useful for identification of chromosome markers of unknown origin, frequently present in malignant diseases. In our case, the fluorescent in situ hybridization allowed us, in a CML patient in accelerated phase, to know the origin of a chromosome marker, and then, to state that the patient had a 21 trisomy added to the Philadelphia chromosome.