Approximately 5-10% of chronic myeloid leukemia (CML) patients are found to have structural or numerical additional chromosomal abnormality (ACAs) in addition to the characteristic t(9;22)(q34;q11.2)BCR/ABL1 at the time of diagnosis.
However, additional cytogenetic abnormalities, including t(3;21) typically seen in therapy-related myelodysplastic syndrome (MDS) and AML and blast crisis of CML, developed as an independent cell line following the autograft.
Rearrangement of the breakpoint cluster region (bcr) was detected in 11 of the 23 patients with Ph-negative CML (48 percent), indicating the presence of the abnormal molecular events in Ph-positive CML without documentation of the Ph cytogenetic abnormality.
Thus, morgana acts as an oncosuppressor with different modalities: (1) Morgana underexpression induces centrosome amplification and cytogenetic abnormalities, and (2) in Ph(+) CML, it synergizes with BCR-ABL signaling, reducing the efficacy of imatinib treatment.
We have shown that patients with a breakpoint within the 5' region of the M-bcr of the bcr gene have a different sub-set of chromosomal bands involved in the cytogenetic abnormalities observed during the development of blast crisis than those patients with a 3' breakpoint.