Cytogenetic investigations of chronic lymphocytic leukemia

[Chromosomal aberrations detection in chronic lymphocytic leukemia by conventional cytogenetics using DSP30 and IL-2]

Objective: To study the value of unmethylated cytosine guanine dinucleotide oligodeoxynucleotide (DSP30) and IL-2 in the conventional cytogenetic (CA) detection of the chromosomal aberrations in chronic lymphocytic leukemia (CLL) . Methods: Bone marrow or peripheral blood cells of CLL patients were cultured with DSP30 plus IL-2 for 72 h, following which R-banding analysis was conducted. Fluorescence in situ hybridization (FISH) was performed in 85 patients. CA results were compared with data obtained by FISH. Results: Among 89 CLL patients, the success rate of chromosome analysis was 94.38% (84/89) . Clonal aberrations were detected in 51 patients (51/84, 60.71%) . Of them, 27 (27/51, 52.94%) were complex karyotype. Among 85 CLL patients tested by FISH, chromosomal abnormalities were detected in 74 (74/85, 87.06%) patients, of which 2 (2/74) patients were complex karyotypes, accounting for 2.70%. Of the 85 CLL patients examined by FISH, 50 had abnormal karyotype analysis, 30 had normal karyotype, 5 failed to have chromosome analysis. Among them, 25 cases showed clonal aberrations by FISH assay but normal by CA, and 4 cases were normal by FISH but displayed aberrations in chromosome analysis, and totally 78 (91.76%) cases with abnormality detected by the combination of the two methods. The frequency of 13q- abnormality detected by FISH was significantly higher than that by CA analysis (69.41%vs 16.67%, P<0.001) , while the frequency of 11q-,+12 and 17p- detected by two methods showed no significant difference (P>0.05) . The detection rate of complex abnormalities in conventional karyotype analysis was higher than that in FISH (50.98%vs 2.70%) . In addition, 11 low-risk and 9 intermediate-risk patients according to FISH results showed complex karyotype by cytogenetics, and were classified into high-risk cytogenetic subgroup. Conclusion: DSP30 and IL-2 are effective in improving the detection rate of CA in CLL patients (60.71%) and CA is more effective to detect complex karyotype. However, FISH had a higher overall abnormality detection rate (87.06%) than CA, especially for 13q-. The combination of CA and FISH not only enhanced the detection rate of clonal aberrations to 91.76%, but also provided more precise prognosis stratification for CLL patients, thus to provide more information for clinical implication.

CpG Oligonucleotide and Interleukin 2 stimulation enables higher cytogenetic abnormality detection rates than 12-o-tetradecanolyphorbol-13-acetate in Asian patients with B-cell chronic lymphocytic leukemia (B-CLL)

The present study was designed to compare abnormality detection rates using DSP30 + IL2 and 12-O-Tetradecanoylphorbol-13-acetate (TPA) in Asian patients with B-CLL. Hematological specimens from 47 patients (29 newly diagnosed, 18 relapsed) were established as 72 h-DSP30 + IL2 and TPA cultures. Standard methods were employed to identify clonal aberrations by conventional cytogenetics (CC). The B-CLL fluorescence in situ hybridization (FISH) panel comprised ATM, CEP12, D13S25, and TP53 probes. DSP30 + IL2 cultures had a higher chromosomal abnormality detection rate (67 %) compared to TPA (44 %, p < 0.001). The mean number of analyzable metaphases and abnormal metaphases per slide was also higher (p < 0.005, p < 0.001, respectively). Culture success rate, percentage of complex karyotype, and percentage of non-clonal abnormal cell were not significantly different (p > 0.05). Thirteen cases with abnormalities were found exclusively in DSP30 + IL2 cultures compared to one found solely in TPA cultures. DSP30 + IL2 cultures were comparable to the FISH panel in detecting 11q-, +12 and 17p- but not 13q-. It also has a predilection for 11q- bearing leukemic cells compared to TPA. FISH had a higher abnormality detection rate (84.1 %) compared to CC (66.0 %) with borderline significance (p = 0.051), albeit limited by its coverage. In conclusion, DSP30 + IL2 showed a higher abnormality detection rate. However, FISH is indispensable to circumvent low mitotic indices and detect subtle abnormalities.

A rare case of t(11;22) in a mantle cell lymphoma like B-cell neoplasia resulting in a fusion of IGL and CCND1: case report

The chromosomal translocation (11;14)(q13;q32) rearranging the locus for cyclin D1 (CCND1) to that of the immunoglobulin heavy chain (IGH) can be found in virtually all cases of mantle cell lymphoma (MCL), while other CCND1 translocations are extremely rare. As CCND1 overexpression and activation is a hallmark of MCL it is regarded as a central biological mechanism in the development and maintenance of this disease.

Here we present a patient initially diagnosed with chronic lymphocytic leukemia (CLL) where chromosome banding analysis revealed, among other aberrations, a translocation (11;22)(q13;q11.2). We show by fluorescence in situ hybridization (FISH) analysis that on chromosome 22 the immunoglobulin light chain lambda (IGL) is involved in this cytogenetic aberration. Additionally, we demonstrate the resulting overexpression of CCND1 on the RNA and protein level, thereby consolidating the new diagnosis of a MCL-like B-cell neoplasia. Summing up, we described a rare case of t(11;22)(q13;q11.2) in a MCL-like neoplasia and showed that this aberration leads to an overexpression of CCND1 which is regarded as a key biological feature in MCL. This case underlines the importance of cytogenetic analyses especially in atypical cases of B cell lymphomas.

Chromosomal aberrations in chronic lymphocytic leukemia detected by conventional cytogenetics with DSP30 as a single agent: comparison with FISH

The aim of our study was to estimate the usefulness for conventional cytogenetics (CC) of DSP30 as a single agent (CC-DSP30) for detecting the most important chromosomal aberrations revealed in CLL by FISH and to find other abnormalities possibly existing but undetected by FISH with standard probes. Using CC-DSP30, the metaphases suitable for analysis were obtained in 90% of patients. CC-DSP30 and FISH were similarly efficacious for detecting del(11)(q22) and trisomy 12, whereas FISH was more sensitive for del(13)(q14). Sole del(13)(q14) detected by FISH, in 50% of patients was associated with other aberrations revealed by CC-DSP30. Additionally, the most recurrent anomaly detected by CC-DSP30 were structural aberrations of chromosome 2.