Double Philadelphia masquerading as chromosome 20q deletion - a new recurrent abnormality in chronic myeloid leukaemia blast crisis

Chromosome 20q deletion: a recurrent cytogenetic abnormality in patients with chronic myelogenous leukemia in remission

del(20q) can be observed in hematologic neoplasms, including chronic myelogenous leukemia (CML), and has been reported in patients undergoing blast transformation. We describe 10 patients with CML in hematologic and cytogenetic remission with del(20q) detected by conventional cytogenetics. There were 6 men and 4 women with a median age of 56 years. All patients initially had BCR-ABL1 and t(9;22) (q34;q11.2) and achieved morphologic and cytogenetic remission after therapy. del(20q) was identified before (2/10 [20%]), at the time of (3/10 [30%]), or after (5/10 [50%]) cytogenetic remission and was not associated with morphologic evidence of dysplasia. At last follow-up, no patients had a myelodysplastic syndrome (MDS). Leukocyte and platelet counts were normal; 4 of 10 patients had mild anemia. Nine patients have remained in morphologic and cytogenetic remission with stable del(20q). BCR-ABL1 fusion transcript levels were absent or low (median, 0.01%). Recently, in 1 patient, recurrent CML developed and del(20q) was lost. We conclude that del(20q) in the setting of CML in remission is not predictive of MDS or blast transformation.

Application of growth factor stimulants improves cytogenetic analysis of chronic myeloproliferative disorder patients without alteration to cell lineage or clonality

Conventional cytogenetic methods rely on culturing bone marrow aspirates to obtain suitable and sufficient mitotic figures for G-banded analysis. Samples from patients with chronic myeloproliferative disorders (CMPD) often have increased failure rates due to reduced growth and poor morphology, all of which hamper the conventional karyotyping investigation. The application of growth factor (GF) stimulants to bone marrow aspirates has been shown to yield significant increases in both the quality and quantity of bone marrow metaphases obtained in 53 CPMD patient samples. All cultures were stimulated using the conditioned supernatant from the human bladder carcinoma cell line 5637, which contains IL-3, IL-6, and G-CSF. Results were assessed qualitatively on G-banded preparations and quantitatively by mitotic index (MI = % dividing cells). To assess whether the application of GF stimulants leads to clonal selection, culture samples from 15 patients were analyzed by fluorescence in situ hybridization, which supported the theory that clonal selection remains unaltered in GF-stimulated cultures. In addition to this immunophenotyping of cells, we demonstrated the lineage of cells propagated under these conditions. Cell markers were chosen to characterize B-lymphoid, T-lymphoid, myeloid, and primitive cell types. Results indicated that T cells were maintained in culture and B-lymphoid markers remained negative. In the myeloid subset, there was an overall reduction in the pan-myeloid markers. We believe this represents the loss of terminally differentiated cells (e.g., neutrophils) in culture. Overall, the study clearly demonstrates that the application of GF stimulants does not alter clonality or cell lineage propagated in these samples and is therefore suitable for application in diagnostic cytogenetic laboratories.