Cytogenetic Analysis of 55 Cases of Philadelphia Chromosome (Ph+) Leukemia

This study aimed to investigate the cytogenetic characteristics of Philadelphia chromosome (Ph) leukemia. (Method) Bone marrow (3 ml) samples were collected from patients with leukemia, prior to any therapeutic treatment. Bone marrow chromosome samples were prepared by short-term culture (24 hours). Karyotype analysis was performed using the R-banding technique. (Result) In total, 308 patients were subjected to karyotype analysis. Among these pa- tients, 55 were diagnosed with Ph positive (Ph+), including 35 cases of chronic myeloid leukemia in chronic phase (CML- CP ) , 8 cases of chronic myeloid leukemia in blast crisis (CML-BC) including 2 cases developed from CML-CP, 12 cases of acute lymphoid leukemia (ALL) , 1 case of acute myeloid leukemia (AML) and 1 case of mixed acute leukemia (MAL) . The frequency of an isolated chromosomal rearrangement event, simple t(9;22) translocation, in CML-CP and CML-BC was 85.7% and 12.5%, respectively, whereas the frequency of t(9;22) with additional chromosomal abnormalities in those two groups was 11.4% and 75%, accordingly. These additional chromosomal abnormalities included +8, +Ph, i(17q), etc. The 2 cases of CML-BC developed from CML-CP were both positive for +8. Among the 12 ALL cases, the frequency of simple t(9;22) and t(9;22) with additional chromosomal abnormalities was 33.3% and 58.3%, respectively. (Conclusion) The predominant chromosomal rearrangement type in CML-CP is simple t(9;22), whereas in CML-BC and ALL, it is usu- ally accompanied with additional chromosomal abnormalities. Monitoring the development of karyotype evolution in pa- tients with CML may be helpful for better understanding the disease progression.