CYP2C19*2 gene variant (G681A, rs4244285) as a prognostic marker for the clinical course of multiple myeloma.

BACKGROUND: Multiple myeloma (MM) is the most common type of paraproteinemic hemoblastosis, which is characterized by an aggressive course, high mortality and a large number of complications. The G681A variant (*2, rs4244285) of the CYP2C19 gene leads to the formation of an inactive enzyme and, as a consequence, may affect the development and course of MM. The aim of this research was to analyze the effect of the G681A variant of the CYP2C19 gene on the risk of the development of MM and its course. MATERIALS AND METHODS: The study enrolled 158 patients with MM, who underwent standard clinical and laboratory studies: cytological, general clinical, biochemical, as well as molecular cytogenetic and molecular genetic. Cytogenetic analysis of chromosome abnormalities was performed using interphase fluorescence in situ hybridization. Genotyping by the G681A variant of the CYP2C19 gene was performed by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: No association was found between the G681A variant of the CYP2C19 gene and the risk of developing MM. The association between the presence of the G allele and GG genotypes with significant changes in clinical and biochemical parameters (plasma cell count, α2-globulin, calcium content) in MM patients has been established. In the presence of the G allele of the CYP2C19 gene, the development of chromosomal rearrangements del(13q14.2) or del(13q34) with significantly increased levels of albumin occurs more frequently. CONCLUSIONS: The G681A variant of the CYP2C19 gene does not affect the risk of developing MM, but it is associated with significant changes in the clinical and biochemical parameters that determine the severity of the disease and its prognosis. Further research is important to develop new target strategies and maintenance therapy for carriers of different variants of the CYP2C19 gene (G681A).

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.

Comparison of chromosomal rearrangements in bone marrow cells and blast transformed B-cells in relapse of B-cell chronic lymphocytic leukemia/small lymphocytic lymphoma.

AIM: The genetic mechanisms of resistance to chemotherapy in B-cell chronic lymphocytic leukemia/small lymphocytic lymphoma (B-CLL/SLL) are not clear. We aimed to determine the peculiarities of abnormal karyotype formation in bone marrow (BM) cells and peripheral blood (PB) blast transformed B-cells in relapse of B-CLL/SLL. MATERIALS AND METHODS: Cytogenetic GTG banding technique and molecular cytogenetic in interphase cells (i-FISH) studies of BM cells and PB blast transformed B-lymphocytes were performed in 14 patients (10 males and 4 females) with B-CLL/SLL. RESULTS: The results of karyotyping BM and PB cells revealed the heterogeneity of cytogenetic abnormalities in combined single nosological group of B-CLL/SLL. In PB B-cells, chromosome abnormalities related to a poor prognosis group were registered 2.5 times more often than in BM cells. Additional near tetraploid clones that occurred in 57.1% cases were the peculiar feature of BM cell karyotypes. Chromosomal rearrangements characteristic of the group of adverse cytogenetic prognosis were revealed in all cases from which in 2 cases by karyotyping BM cells, in 6 cases in PB B-cells and in 8 cases by the i-FISH method in BM cells, i.e. their detection frequency was 3 times higher in PB B-cells and 4 times higher when analyzing by i-FISH in BM cells. CONCLUSIONS: Mismatch in abnormal karyotypes in BM and PB B-cells by the presence of quantitative and structural chromosomal rearrangements may be indicative of simultaneous and independent processes of abnormal clone formation in the lymph nodes and BM hematopoietic cells. Accumulation the information about previously unidentified chromosomal rearrangements in relapse of the disease may help to understand the ways of resistance formation to chemotherapy.

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.

mTOR inhibitor temsirolimus and MEK1/2 inhibitor U0126 promote chromosomal instability and cell type-dependent phenotype changes of glioblastoma cells.

The phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) and the RAF/mitogen-activated and extracellular signal-regulated kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling pathways are frequently deregulated in cancer. Temsirolimus (TEM) and its primary active metabolite rapamycin allosterically block mTOR complex 1 substrate recruitment. The context-/experimental setup-dependent opposite effects of rapamycin on the multiple centrosome formation, aneuploidy, DNA damage/repair, proliferation, and invasion were reported. Similarly, the context-dependent either tumor-promoting or suppressing effects of RAF-MEK-ERK pathway and its inhibitors were demonstrated. Drug treatment-mediated stress may promote chromosomal instability (CIN), accelerating changes in the genomic landscape and phenotype diversity. Here, we characterized the genomic and phenotypic changes of U251 and T98G glioblastoma cell lines long-term treated with TEM or U0126, an inhibitor of MEK1/2. TEM significantly increased clonal and non-clonal chromosome aberrations. Both TEM and U0126 affected copy number alterations (CNAs) pattern. A proliferation rate of U251TEM and U251U0126 cells was lower and higher, respectively, than control cells. Colony formation efficiency of U251TEM significantly decreased, whereas U251U0126 did not change. U251TEM and U251U0126 cells decreased migration. In contrast, T98GTEM and T98GU0126 cells did not change proliferation, colony formation efficiency, and migration. Changes in the sensitivity of inhibitor-treated cells to the reduction of the glucose concentration were observed. Our results suggest that CIN and adaptive reprogramming of signal transduction pathways may be responsible for the cell type-dependent phenotype changes of long-term TEM- or U0126-treated tumor cells.

[Heterogeneity of chromosomal abnormalities in acute myeloid leukemia in different age groups children].

Characteristic of chromosomal abnormalities in bone marrow cells among 123 children with acute myeloid leukemia were presented according five aging groups: I - up to 2 years, II - 2-5 years, III - 5-10 years, IV - 10-15 years, V - 15-18 years. Normal karyotype wasn't found in group up to 2 years and in low presented in another groups (5, 9-10,3%). The highest frequency of chromosomal abnormality evolution in group up to 2 years was established (69,2%). The highest frequency of hyperdiploidy (47-50 chromosomes) in group 15-18 years (31%) was found. More often near-tetraploidy and pseudodiploidy clones were met in group 2-5 years (47% and 58,8%, respectively). Between structural types in all groups were predominated translocations and deletions. In group up to 2 years was prevalented translocations (61,5%), 2-18 years - deletions (64,7; 34,5; 45,7 and 41,4 % respectively). In group up to 2 years more often were met abnormalities chromosomes (Chr) 9, 11, 16 (in 30,8%), 2-5 years - Chr 16, 21 (in 29,4%), 5-10 years - Chr 11 (24,1%), 8, 15, 17 (in 17,2%), 10-15 years - Chr 16 (40%) and 15-18 years - Chr 8, 9, 15, 17 (in 17,2%).