Peculiarities of abnormal karyotypes formation in therapy-related acute leukemias

To determine ways of formation of abnormal karyotypes in two clinical cases of secondary acute leukemias of myeloid and lymphoid lineages.

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.

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.

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.