Peculiarities of abnormal karyotypes formation in therapy-related acute leukemias.

AIM: To determine ways of formation of abnormal karyotypes in two clinical cases of secondary acute leukemias of myeloid and lymphoid lineages. MATERIAL AND METHODS: Bone marrow cells of one patient with therapy-related acute monoblastic/monocytic leukemia and one patient with therapy-related acute lymphoblastic leukemia were examined by cytogenetic GTG banding technique. RESULTS: An unusually large number of quantitative and structural anomalies of chromosomes in therapy-related acute monoblastic/monocytic leukemia have been established, which have many features in common with chromothripsis, namely instability of clones that manifested itself through quantitative anomalies (trisomy, monosomy, marker chromosomes, including chromosome 5), structural - t(9;11), deletions of the long arm of chromosomes 8 and 14, derivatives of chromosomes 3 and 7, ring chromosomes. In case of secondary acute lymphoblastic leukemia, the anomalous clone with balanced translocation in all 20 metaphase plates 46,XX,t(1;15)(p21;q24) has been registered, which is not described in the literature. Therefore, the diagnostic and prognostic value of such anomaly is unknown. CONCLUSIONS: Rearrangement with the involvement of the locus 11q23 was recorded in the case of chemotherapy treatment without topoisomerase II inhibitors. The complex karyotype formed after chemotherapy and radiotherapy, which is a criterion for an unfavorable prognosis of the disease, is considered as the equivalent of chromothripsis. t(1;15) is considered as an abnormality that can be attributed to the group of favorable secondary acute lymphoblastic leukemia prognosis.

Chronic myeloid leukemia in patient with the Klinefelter syndrome.

AIM: Genetic inborn along with acquired diseases arise due to the lesions in genome of multipotent hematopoietic stem cells. The aim was to study an influence of constitutional anomaly, Klinefelter syndrome, and additional structural rearrangements on the BCR-ABL tyrosine kinase inhibitor targeted therapy efficacy. MATERIAL AND METHODS: We describe a 32-year-old male patient with chronic myeloid leukemia (CML) who was detected to have sex chromosomal abnormality during evaluation for Philadelphia chromosome. RESULTS: At diagnosis of CML, two clones were detected by standard cytogenetic investigation of bone marrow cells: 1) clone with translocation t(9;22)(q34;q11), with two sex X chromosomes and absence sex chromosome Y; 2) clone with t(9;22) and unbalanced t(Y;20)(q11;q13). Analysis of blast transformed lymphocytes from peripheral blood showed karyotype 47,XXY. Monitoring of targeted therapy with second generation inhibitor of BCR-ABL tyrosine kinase indicated a cytogenetic remission and absence of BCR-ABL1 fusion signals after 11 months. CONCLUSIONS: Absence of translocation t(9;22)(q34;q11) in blast transformed T-lymphocytes at diagnosis of CML evidences that this translocation may appear not only at the level of multipotent haemopoietic cell progenitors but also may have oligo lineage myeloid origin. Presence of additional structural chromosomal abnormality in the clone with t(9;22)(q34;q11) does not affect the efficacy of therapy with the use of second generation BCR-ABL tyrosine kinase inhibitor.