Different cell clones in bone marrow and spleen of a patient with chronic myelocytic leukemia (CML) in blastic phase

Molecular, Cytogenetic, and Hematological Analysis of Chronic Myeloid Leukemia Patients and Discovery of Two Novel Translocations

Chronic myeloid leukemia (CML) is a disease of hematopoietic stem cells and is caused by the balanced translocations among the long arms of chromosomes 9 and 22, which are called the Philadelphia (Ph) chromosome. In this study, 131 CML patients were enrolled. Complete blood cell count was performed at the time of diagnosis for all the patients. Cytogenetic (karyotyping) examination using bone marrow samples was conducted on 76 CML patients for the confirmation of Ph-positive (9;22)(q34;q11) standard translocation, complex variant translocation, and additional chromosome abnormalities. FISH was performed on 38 patients for diagnostic purposes and on 39 patients for monitoring purposes. Twenty-two samples of CML patients were evaluated by reverse transcriptase PCR and real-time PCR for the patients who failed to respond against imatinib mesylate. In this study, 72 (54.96%) were males and 59 (45.03%) were females with a median age of 38.5 years. CBC values in the diagnosis process showed that 75 patients had high values of WBC being >100 × 103/μl, while 71 (58.01) patients exhibited reduced values of hemoglobin, i.e., <10.00 mg/dl, and high values of PLTs > 100 were observed in 40 (30.53%) patients. Cytogenetic results show that standard translocation was developed in 63 (82.89%), development of complex variant translocations in 4 (5.32%), additional chromosomal abnormalities (ACAs) in 3 (3.94%), and ACAs together with complex variant translocations in 1 (1.31%) patient. At the time of diagnosis, 61 (92.95%) patients were in the chronic phase, 4 (5.63%) were in the accelerated phase, and only 1 (1.40%) was in the blast crisis. Out of twenty-two patients, only 6 CML patients who were shifted from imatinib mesylate to nilotinib showed BCR-ABL-positive amplification. However, only 7 out of twenty-one patients exhibit BCR-ABL gene values ≥ 1 after three months of follow-up when analyzed by the quantitative real-time PCR. In conclusion, we found a novel five-way translocation 46XX,t(1;2;2;17;9;22)(p36.3,q21;q11.2,q21,q34,q11.2) and a novel four-way complex variant translocation 48XY,+8(8;17)(9;22),+der(22)(q11.2;q23)(q34;q11.2) in the accelerated phase.

Coexistence of myeloid and lymphoid neoplastic subpopulations in chronic myelogenous leukemia

Serial cytogenetic studies have been performed on a child with Philadelphia chromosome (Ph1)-positive chronic myelogenous leukemia (CML) and correlated with clinical, morphologic, and cytochemical data in an attempt to elucidate further the natural history of leukemia progression observed in this disease. Once the initial blast crisis had occurred, two genetically different leukemic clones of cells, one presumably having arisen from the other, coexisted throughout the remainder of the patient's course. The initial clone comprised differentiating myeloid cells, while the second clone appeared on morphologic and cytochemical grounds to be lymphoid and blastic. A dynamic equilibrium existed between these two populations of cells, with the balance altered by chemotherapy and/or other selective pressures. The leukemic progression demonstrated in this case is consistent with the concept of clonal evolution of malignant cell populations. In planning therapy, it may be necessary to consider each of these coexistent clones and their different therapeutic requirements.