Detection of chromosome abnormalities using cytoplasmic immunoglobulin staining and FISH in myeloma.

The low proliferation rate of myeloma cells in vitro can result in a normal cytogenetic karyotype with the abnormal cell population not being detected. Because plasma cell myeloma is a patchy disease, conventional FISH is also hampered by normal cell contamination. Identification of plasma cells by cytoplasmic immunoglobulin staining in combination with FISH (cIg FISH) can ensure that only the cells of interest are analyzed, and thus the results obtained are a more accurate reflection of the plasma cell population karyotype.

Gene amplification in myeloid leukemias elucidated by fluorescence in situ hybridization.

Gene amplification in hematologic malignancies is uncommon. When karyotyping leukemia cells, gene amplification is generally seen as double-minute (dmin) chromosomes and homogeneously staining regions (hsr). One of the more commonly amplified regions is MYC at 8q24.

BCR/ABL amplification in chronic myelocytic leukemia blast crisis following imatinib mesylate administration.

The onset of accelerated phase or blast crisis of chronic myelocytic leukemia (CML) is usually associated with the acquisition of new chromosome abnormalities in addition to the t(9;22)(q34;q11) that is characteristic of the chronic phase CML. We describe the cytogenetic and molecular genetic findings in two cases of myelocytic blast crisis of CML, one occurring 6 months after commencing treatment with the ABL-specific tyrosine kinase inhibitor imatinib mesylate (STI571, Glivec, or Gleevec) and the second treated with imatinib mesylate for established blast crisis. In both cases, multiple secondary cytogenetic abnormalities were observed at transformation, with homogeneously staining regions that were shown to contain BCR/ABL amplification by fluorescence in situ hybridization appearing after imatinib mesylate administration.

Appearance of del(11q) in two patients with acute promyelocytic leukaemia treated with all-trans retinoic acid and combination chemotherapy.

Two acute promyelocytic leukaemia patients, treated with all-trans retinoic acid and combination chemotherapy, acquired a deletion of 11q within 12 months of diagnosis. One patient died in relapse, with both t(15;17) and del(11q) cell lines co-existing. Patient 2 remains in remission with del(11q) in 70% metaphases, despite normal marrow morphology.