Trisomy 12 in chronic lymphocytic leukemia and hairy cell leukemia: a cytogenetic and interphase cytogenetic study

Listeria monocytogenes Infection in Hairy Cell Leukemia: A Case Report and Literature Review

Listeria monocytogenes infections have been described in patients with diverse types of malignancy, especially leukemia. We report the case of a 65-year-old man with previously untreated hairy cell leukemia characterized by CD5 positivity and trisomy 12 (3% of blood lymphocytes) who developed bacteremia due to L. monocytogenes serotype 1/2b. We summarize clinical features and treatment of this patient and five previously reported patients with hairy cell leukemia who also had L. monocytogenes infections. All six patients were men. Their mean age at infection diagnosis was 70 y. Three men had undergone splenectomy 4–11 y before they developed L. monocytogenes infection. The central nervous system was the primary site of infection in four men. Bacteremia alone occurred in two other men. At diagnosis of infection, one man was receiving antileukemia chemotherapy and another man was receiving treatment for Kaposi's sarcoma. Two other patients had other comorbid conditions. All six men recovered from their infections.

A variant chronic B-cell lymphoma characterized by villous cells with novel immunophenotypic and cytogenetic profiles

The less common chronic B-cell lymphomas include hairy cell leukemia, hairy cell leukemia variant and splenic lymphoma with villous lymphocytes. These disease entities can sometimes cause a diagnostic dilemma; however, immunophenotypic markers have been identified as disease specific and scoring systems have been proposed to assist the process. This study reports a case of a chronic B-cell lymphoma with long cytoplasmic projections which does not fit into any of the published disease categories based upon a combination of clinical and morphological features and immunophenotyping. Furthermore, this case featured a combination of cytogenetic abnormalities not previously described in the published literature in association with a B-cell lymphoproliferative disorder.

The variant form of hairy-cell leukaemia

Hairy-cell leukaemia-variant (HCL-variant) is a rare B-cell disorder which accounts for 10% of HCL cases. It affects elderly or middle-aged males. The main features are splenomegaly, lymphocytosis and cytopenias without monocytopenia. The circulating cells have a morphology intermediate between prolymphocytes and hairy cells. The immunophenotype shows a mature B-cell phenotype with expression of the B-cell antigens CD11c and CD103-but unlike typical HCL the cells are CD25- and HC2-negative. The histology of bone marrow and spleen shows a pattern of infiltration similar to that in HCL. There is no recurrent chromosomal abnormality but complex karyotypes and monoallelic p53 deletion by fluorescence in situ hybridization are common. Patients are resistant to alkylating agents and interferon-alpha (IFN-alpha) and only half achieve partial responses to pentostatin and/or cladribine. Splenectomy results in long-lasting partial responses in over two-thirds of the patients and is a good palliative treatment. Despite the lack of response to most therapies, the clinical course of HCL-variant is chronic. The median survival is 9 years and 42% of patients die of unrelated causes. Transformation to large cell is seen in 6% of patients. The inferior survival in HCL-variant compared with typical HCL cases may reflect the chemotherapy resistance.

TP53 deletions but not trisomy 12 are adverse in B-cell lymphoproliferative disorders

Abnormalities of the TP53 tumor suppressor gene at 17p13.1 are prognostically adverse in a variety of hematolymphoid malignancies. The present study utilized interphase fluorescence in situ hybridization (I-FISH) to detect TP53 deletions and trisomy 12 in 101 clinical specimens from 98 patients with B-cell lymphoproliferative disorders (B-LPDs). Twelve patients had TP53 deletions (group A), 23 had trisomy 12 (group B), and 63 had neither (group C). The groups did not significantly differ in age, duration of disease, absolute lymphocyte count, or percentage with an immunophenotype or cytology atypical for chronic lymphocytic leukemia (CLL). The clinical stage of disease and lactate dehydrogenase (LDH) level were higher in group A, with less response to therapy. After a median follow-up of 19 months, seven of the patients in group A had died of disease (another patient subsequently has had large cell transformation) compared with none in group B and nine in group C. Multivariate analysis found the stage of disease and TP53 deletions as the only parameters independently associated with shortened survival (P < 0.001). Thirty-nine patients had conventional cytogenetic analysis (CCA) which was complexly abnormal in 11 patients; 6 of whom died of disease. There was a trend for complex cytogenetics to be seen more frequently in group A, often with 17p involvement. For most laboratories, CCA may be the preferable initial study to identify prognostically different subgroups of B-LPDs. However, as more probes and clinical outcome data become available, I-FISH will likely play an increasingly important ancillary role.

Chronic lymphoproliferative disorders: an integrated point of view for the differential diagnosis

Morphology is regarded as the principle basis for the identification of lymphoid neoplasms. Sometimes, however, it fails to discriminate among several chronic lymphoproliferative disorders (CLDs). Improved immunophenotyping has resulted in a better characterization of a number of variants of these diseases, some of which may benefit from different therapeutic approaches. In particular, the proposal of scoring systems using a panel of monoclonal antibodies (MoAbs) has represented a critical step in this field. In fact, to date, some MoAbs (CD5, CD23, FMC7, CD22, CD79b, and surface immunoglobulin density) are able to distinguish among several entities, thus allowing for a correct diagnosis in the majority of cases. However, there is still a small percentage of patients where the combined diagnostic approach (morphology and immunophenotyping) should be further refined by other techniques, such as cytogenetic and molecular characterization. Here numerous questions are raised indicating the need to more accurately differentiate the disease entities under discussion and better understand some of their clinical manifestations.

p53 gene deletion and trisomy 12 in hairy cell leukemia and its variant

The deletion or mutation of the p53 tumour suppressor gene on chromosome 17p13 is known to be associated with aggressive disease in several B-cell malignancies. The present study describes the p53 gene status in 20 cases of hairy cell leukemia (HCL) and in 12 cases of its morphological variant (HCL-V) by fluorescence in situ hybridization (FISH). A high incidence of p53 deletion was found in both diseases (75-100% of cases). However, a significant difference was observed between the proportion of cells with p53 deletion in HCL-V cases (mean 31%) and HCL cases (mean 12%) P value < 0.01. The observed difference correlates with the well known tendency for transformation and poor response to therapy in HCL-V and seven cases of HCL-V with greater than 22% of cells with p53 deletion showed features of disease progression and transformation. Trisomy 12 was present in 8.5% of the cells in one case of HCL-V and in 6-8% of cells in three cases of HCL.

Cytogenetic findings in five patients with hairy cell leukemia

We studied five cases of hairy cell leukemia (HCL) using conventional cytogenetics. All patients were diagnosed with typical HCL. Chromosome analysis was carried out on a 72-hour culture of peripheral blood. Phytohemagglutinin (PHA) mitogen was used. Clonal chromosome abnormalities were found in 2/5 patients (40%), a complex abnormality being identified in one of them. The chromosomes involved were: 1, 6, 7, 8, and 17. No patient showed trisomy 12 or a 14q+. An interesting result was the finding of del(7)(q32) as a sole anomaly.

Characterization of a hairy cell leukemia-associated 5q13.3 inversion breakpoint

Previous cytogenetic analysis has indicated that chromosome anomalies involving the 5q13 band are common in hairy cell leukemia (HCL), occurring in approximately 1/3 of the patients. The data suggest that 5q13.3 is likely to harbor a gene involved in the transformational event of this disease. We selected a constitutional inv(5)(p13.1q13.3) in a patient with HCL as the starting point in an attempt to identify the relevant gene in 5q13.3. By using double color interphase fluorescence in situ hybridization (FISH) techniques, we have identified two cosmid probes from a chromosome 5-specific library that flank the 5q13.3 inversion breakpoint proximally and distally. Pulsed field gel electrophoresis (PFGE) and interphase FISH experiments suggest that the two markers are at a distance of no more than 300 kb. YAC probes covering a 21 Mb region at 5q13 were used to map the 5q13.3 inversion breakpoint and the breakpoint is located within the D5S646-D5S620 region. Two non-chimeric YACs have been identified that span the breakpoint. FISH analysis revealed that four other patients with cytogenetic aberrations of 5q carried inversions/deletions that involved the same 5q13.3 breakpoint region. The identification of a gene involved in hairy cell leukemogenesis in this region will be of major importance in the elucidation of the transformational events of HCL.

Interphase cytogenetics in chronic lymphocytic leukemia

The incidence of trisomy 12 and 13q12-q14 abnormalities in patients with chronic lymphocytic leukemia (CLL) was determined by conventional cytogenetics and interphase fluorescence in situ hybridization (FISH). In the analysis of 580 consecutive patients, trisomy 12 was detected by conventional cytogenetics in 39 cases (9%) and 117 cases (20%) by FISH. Trisomy 12 was shown to be associated with advanced clinical stage, atypical morphology, and higher proliferative activity. Combined immunophenotyping and FISH showed that trisomy 12 was present only in a proportion of the clonal B-cells. These data suggest that trisomy 12 is a secondary event associated with features of disease progression. Sequential FISH showed clonal progression of the trisomic clone over time. Three hundred patients also were investigated for 13q deletions using FISH analysis of the RB1 locus (13q14). Monoallelic RB1 deletion was seen in 104 (34%) of cases. One case had a homozygous deletion in 90% of the cells. Dual-color FISH detected the presence of trisomy 12 and RB1 in 17 (5%) cases. DNA probes for 13q12.3 (BRCA2) and 13q14 (RB1 and DBM locus) were used in 35 cases. Twenty-eight (80%) cases showed deletion of a 1Mb 13q12.3 encompassing the BRCA2 locus, whereas 22/35 (63%) were deleted at 13q14. Our data suggest that abnormalities of 13q are more frequent than trisomy 12 in CLL and provide evidence for the presence of a new candidate gene at 13q12.3 that may be involved in the pathogenesis of CLL.

Genetic abnormalities in chronic lymphocytic leukemia and their clinical and prognostic implications

Clonal chromosome abnormalities can be detected in approximately 50% of patients with chronic lymphocytic leukemia (CLL). The most common changes are trisomy 12, followed by structural abnormalities of 13q, 11q, 6q, and 14q. By fluorescence in situ hybridization (FISH), these aberrations can be demonstrated even in cases with insufficient mitotic yield or a normal karyotype. The biologic consequences of trisomy 12 are unknown, but a gene dosage effect is suspected and studies on partial trisomy 12 indicate that the region 12q13 to 12q22 might be of particular pathogenetic importance. Trisomy 12 is strongly associated with atypical lymphocyte morphology and seems to be a secondary event in leukemogenesis, as shown by combined immunophenotyping and interphase FISH. Structural abnormalities of 13q frequently involve hetero- and homozygous deletions of a region in 13q14, distal to the retinoblastoma gene, which may be the site of a tumor suppressor gene. In contrast to a normal karyotype or structural changes of 13q, complex karyotypic abnormalities, high percentage of abnormal metaphases, trisomy 12 and structural changes involving the P53 tumor suppressor gene on 17p13 are adverse prognostic indicators. Cytogenetic and molecular findings provide important diagnostic, clinical, and prognostic information which can contribute to treatment decisions and follow-up of CLL patients.

Fluorescence In Situ Hybridization: Trisomy 12 Follow-up In Hairy Cell Leukemia

Peripheral white blood cells from five patients with hairy cell leukemia (HCL) were studied applying fluorescence in situ hybridization (FISH) using heparinized peripheral blood, biotin-labeled chromosome 12-specific α satellite DNA probe and biotin fluorescein-labeled avidin to detect hybridization. This methodology is ideal to investigate the incidence of numerical chromosomal abnormalities of both interphase and metaphase cells. Blood samples from 28 normal subjects were included as control samples. Trisomy 12 was considered to be present when ≥4% of cells had three hybridization spots. Trisomy 12 was detected in three of the five patients at different stages of their evolution. Trisomy 12 was also evident in two patients upon relapse of the HCL. When treatment with interferon alfa (IFN) and steroids was started, clinical and analytical remission were achieved and trisomy 12 disappeared. In one patient trisomy 12 persisted regardless of treatment with IFN and a good clinical evolution. Our results show that trisomy 12 was detected in HCL with FISH at a higher frequency than that previously reported by cytogenetic analysis in either peripheral blood or in cultivated cell lines. These results indicate that the presence of trisomy 12 may be a useful marker for the presence of HCL cells, to check the percentage of trisomic cells and that trisomy 12 is also a useful marker to indicate the activity of the disease.

Heterogeneity of lineage involvement by trisomy 8 in myelodysplastic syndrome. A multiparameter analysis combining conventional cytogenetics, DNA in situ hybridization, and bone marrow culture studies

To better understand the role of trisomy 8 in myelodysplastic syndrome (MDS), we performed a multiparameter analysis combining conventional chromosome studies (CCS), fluorescence in situ hybridization (FISH), and bone marrow (BM) culture studies in two patients with MDS evolving into acute myeloid leukemia (AML). A mosaicism of a cytogenetically normal clone and a clone with trisomy 8 was detected in both patients throughout the course of the disease, a finding confirmed by FISH on BM cells. The relative size of the trisomic clone increased from 52% to 71% (p < 0.0001) and from 53% to 69% (p = 0.001) of all BM cells at the time of the leukemic switch in patients 1 and 2, respectively. Combined FISH and immunophenotyping of BM cells showed involvement of the granulomonocytic lineage in patient 1 and involvement of erythroid cells as well as of the granulomonocytic lineage in patient 2. Only disomic lymphocytes were detected in both patients. FISH on single hemopoietic colonies grown in semisolid media detected trisomic CFU-GM and disomic BFU-E in patient 1, whereas a proportion of CFU-GM and BFU-E deriving from the trisomic clone was detected in patient 2. However, the percent of trisomic colonies was lower than the percent of involved granulomonocyte precursors and involved erythroblasts, as detected by combined FISH and immunophenotyping on fresh BM samples. We have thus shown heterogeneity of lineage involvement by trisomy 8 in MDS undergoing transformation into AML. Although preferential growth of disomic clones may occur in vitro, the finding of an increased size of the trisomic clone at the time of leukemic switch suggests that these cells had proliferative advantage in vivo over cells without trisomy 8.