High incidence of unbalanced chromosomal changes in mantle cell lymphoma detected by comparative genomic hybridization.

Comparative genomic hybridization (CGH) was carried out in 30 mantle cell lymphoma (MCL) patients at the time of diagnosis. CGH results were supported by conventional cytogenetics (CC), FISH, molecular genetic PCR methods and 2 patients were examined by array CGH. Using all cytogenetic, molecular cytogenetic and PCR methods, chromosomal changes were detected in 28 (93%) patients. Using CGH, unbalanced chromosomal changes were detected in 24 (80%) cases. The most frequent aberrations were losses of 1p (8 cases), 8p (10 cases), 9q (6 cases), 11q (11 cases), 13q (10 cases) and 17p (9 cases), and gains of chromosome 3 and 3q (12 cases) and 8q (7 cases). Total number of 60 gains and 116 losses were detected. The primary chromosomal change t(11;14) was detected using FISH and/or PCR in 20 (66.6%) patients, and in 9 of them, the breakpoint was determined using PCR in the major translocation cluster (MTC). The evaluation of the frequencies of CGH changes in groups of patients with and without t(11;14) revealed the differences only in losses 6q and 9q, which were only found in patient with t(11;14). An important result was obtained using array CGH method. In a patient without the primary t(11;14), the gain of CCND1 gene was found. Our results show high heterogeneity of the additional chromosomal changes in MCL cases, which involved specific chromosomal subregions. We did not confirm the importance of subdividing of MCL cases with and without t(11;14). Also, statistical significance in survival rates between both subgroups was not confirmed.

Complex karyotypes in childhood acute lymphoblastic leukemia: cytogenetic and molecular cytogenetic study of 21 cases.

Cytogenetic and molecular cytogenetic analysis of 79 childhood acute lymphoblastic leukemias (ALL) revealed chromosomal abnormalities in 76 (96%). Complex karyotypes (a finding of three and more chromosomal aberrations in a karyotype) were identified in 21 (26.6%) out of 79 patients. In 11 patients, complex karyotypes have included common recurrent chromosomal abnormalities, such as translocation t(12;21) in seven cases, t(9;22) in two cases, one case with t(2;1;19) and another one with translocation involving 11q23. In 10 patients, miscellaneous abnormalities were detected. Five patients displayed hyperdiploidy (47 approximately 57 chromosomes), three patients complex karyotypes with deletions of 9p, one patient with two new complex translocations t(2;4;12;13) and t(7;11;20), and the last patient with dic(12;21). The evaluation of the frequency of the chromosomal breaks (>5 per chromosome) showed that chromosomes 2, 4, 5, 7, 9, 12, 13, and 21 were most frequently affected. Survival analysis revealed statistically significant unfavorable event-free survival (EFS) (P=0.013) and decreased overall survival in the group with complex karyotypes (n=21) compared with the other cases (n=58). The evaluation of overexpression profile revealed increased occurrence of double CD13/CD33 positivity in patients with common recurrent chromosomal abnormalities (in 70% of cases); no such cases were registered in the other group (P<0.01).

Contribution of comparative genomic hybridization and fluorescence in situ hybridization to the detection of chromosomal abnormalities in B-cell chronic lymphocytic leukemia.

BACKGROUND: B-chronic lymphocytic leukemia (B-CLL), the most common type of leukemia in Western Europe and the United States, is characterized by clonal chromosomal abnormalities detected in almost half of the studied patients. The precise determination of chromosomal changes helps to indicate the prognosis and to understand the pathogenesis of CLL. METHODS AND PATIENTS: We applied conventional cytogenetics (CC), FISH and comparative genomic hybridization (CGH) to the investigation of clonal abnormalities in 88 B-CLL patients at the time of diagnosis. RESULTS: By using CC of bone marrow cells without any stimulation, non-random chromosomal changes were found in 17 (19%) of 88 patients. The employment of FISH and CGH revealed chromosomal changes in additional 33 patients, thus increasing the detection rate of chromosomal abnormalities to 57%. The most common abnormalities detected in our patients included deletions of 13q in 16 cases (18%), followed by trisomy of chromosome 12 in 12 patients (13%), deletions of 11q in 10 patients (11%) and deletions of 17p in 10 patients (11%). A statistically significant correlation between higher disease activity and the presence of deletions 11q and 17p was observed. CONCLUSION: The addition of FISH and CGH to CC in 88 B-CLL patients improved the detection of clonal chromosomal changes from 19 to 57%. The most frequent chromosomal change was deletion of 13q14 (18%). Deletions of 11q23 and 17p13 were found in patients with higher clinical disease activity. Our results underline the importance of employing FISH and CGH techniques in CLL patients. CC without any stimulation has a low detection rate and is not suggested for detection of chromosomal changes in CLL.

[Methods in molecular cytogenetics for determination of prognostically important chromosome changes in patients with chronic lymphatic leukemias]. / Prínos metod molekulární cytogenetiky pro urcení prognosticky významných chromozomových zmen u nemocných s chronickou lymfatickou leukémií.

BACKGROUND: We applied classical cytogenetics, FISH and CGH to investigate prognostic important chromosomal changes, deletions of 17p, 11q and trisomy of chromosome 12 in 90 B-CLL patients at the time of diagnosis. METHODS AND RESULTS: Using classical cytogenetics the chromosomal changes were detected in 17 (18%) patients. Trisomy 12 was found in three patients, deletion 11q in two patients and deletion 17p in four patients. The employment of FISH and CGH revealed chromosomal changes in 52 (58%) patients, the trisomy of chromosome 12 was detected in 12 (13%) patients, the deletions of 11q and deletions of 17p in 10 patients (11%). Statistically significant correlation between higher disease activity and the stage of disease and the presence of deletion 11q and 17p was found. The trisomy of chromosome 12 was found in patients with abnormal markers and in patients with higher stage of the disease. CONCLUSIONS: According to our results, the majority of chromosomal abnormalities in B-CLL may escape detection when classical cytogenetics is the only diagnostic technique used. It stresses the importance of employing additional techniques including FISH and CGH at the time of diagnosis.