Interphase cytogenetics on agar cultures: a novel approach to determine chromosomal aberrations in hematopoietic progenitor cells.

We describe a novel approach to determine the presence of chromosomal aberrations in progenitor cells by in situ hybridization (ISH) on agar cultures. Bone marrow cells of 3 patients suffering from acute myeloid leukemia (AML) were selected to develop the method. In all 3 cases, numerical aberrations for chromosome 1 and/or 8 were detected by karyotyping and ISH using chromosome-specific centromeric-associated DNA probes. These aberrations were used as markers in this study. After in vitro culture of the bone marrow samples in agar, the cells were pretreated to perform ISH. This approach retains the cytological architecture of the agar assay, allowing discrimination between chromosomal aberrations detected in the clonogenic and non-clonogenic cells in culture. With this new technique, the presence of the cytogenetic aberration in clonogenic cells can be shown at the interphase level.