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Philadelphia chromosome (Ph) positive chronic myelocytic leukemia (CML): frequency of additional findings
Insights
This study analyzed cytogenetic abnormalities in 79 chronic myelocytic leukemia (CML) patients. While most had typical Philadelphia chromosome (Ph)-positive CML, some exhibited complex translocations and additional chromosomal changes, particularly during blast crisis.
Area of Science:
- Hematology
- Cytogenetics
- Oncology
Background:
- Chronic myelocytic leukemia (CML) is characterized by the Philadelphia chromosome (Ph).
- Understanding cytogenetic variations is crucial for CML prognosis and treatment.
Purpose of the Study:
- To document cytogenetic findings in Ph-positive CML patients.
- To identify unusual translocations and additional chromosomal abnormalities.
Main Methods:
- Cytogenetic analysis using different banding techniques on bone marrow and peripheral blood samples.
- Study included 79 patients, with 70 in chronic phase and 8 in blast crisis.
Main Results:
- Three patients (4.3%) in chronic phase had unusual or complex translocations.
- Loss of the Y chromosome was observed in 13.3% of males.
- Blast crisis cases frequently showed additional chromosomal abnormalities, including +8, +10, +19, and others.
Conclusions:
- Atypical translocations and secondary chromosomal changes occur in Ph-positive CML.
- These abnormalities are more prevalent during the blast crisis phase.
- Further investigation is needed for secondary translocations in blast crisis.
Abstract:
This article documents the cytogenetic findings in 79 patients with typical Ph-positive chronic myelocytic leukemia (CML). Direct preparations of bone marrow and/or peripheral blood of 46 males and 33 females were studied with different banding techniques. Seventy patients were studied during chronic phase. Three (4.3%) had unusual or complex translocations: t(6;22)(p21;q11), t(8;12;9;22)(p21;q21;q34;q11), and t(9;11;22)(q34;q13;q11). One (1.4%) had a +Ph, 1 (1.4%) had a +8, 1 (1.4%) had a del(3)(p13,p23), and 4 of 30 males (13.3%) showed loss of Y chromosome. Five of 8 cases studied during blast crisis had additional abnormalities. The +8 occurred in 4 cases, +10 and +19 each in 3 cases, +6, + 9q+, and +13 each in 2 cases, and +5, +11, +14, +21, +Ph, i(17q), dic(1;9), and structural abnormalities of chromosomes #1, #5, #12, and #13 each in 1 case. Two cases studied in blast crisis alone had complex translocations leading to the Ph. Because it cannot be ruled out that these translocations are secondary, they were not included in the calculation of the frequency of atypical translocations.