The prognostic significance of 13q14 deletions in chronic lymphocytic leukemia

Patterns of Chromosomal Aberrations in Solid Tumors

Chromosomal abnormalities are a defining feature of solid tumors. Such cytogenetic alterations are mainly classified into structural chromosomal aberrations and copy number alterations, giving rise to aneuploid karyotypes. The increasing detection of these genetic changes allowed the description of specific tumor entities and the associated patterns of gene expression. In fact, tumor-specific landscapes of gross genomic copy number changes, including aneuploidies of entire chromosome arms and chromosomes result in a global deregulation of the transcriptome of cancer cells. Furthermore, the molecular characterization of cytogenetic abnormalities has provided insights into the mechanisms of tumorigenesis and has, in a few instances, led to the clinical implementation of effective diagnostic and prognostic tools, as well as treatment strategies that target a specific genetic abnormality.

The Use of FluorescenceIn SituHybridization (FISH) in Chronic Lymphocytic Leukemia (CLL)

As a result of the low proliferative index, only 50% of chronic lymphocytic leukemia cases are adequate for cytogenetic analysis. Of these, about half have clonal abnormalities. The application of fluorescence in situ hybridization (FISH) to CLL has substantially enhanced our ability to detect chromosomal aberrations; the incidence of a number of recurring abnormalities has been established, providing new insights into the pathogenesis of this disease with a direct impact on the prognosis.

Subclinical chronic lymphocytic leukaemia associated with a 13q deletion presenting initially in the skin: apropos of a case

INTRODUCTION

B-cell chronic lymphocytic leukaemia (B-CLL) represents a low-grade B-cell lymphoproliferative disease that is the most common leukaemia in adults. The neoplastic cell is an autoreactive CD5 CD23 B lymphocyte. B-CLL may involve the skin, typically in the context of known disease. We present a case of subclinical B-CLL presenting initially in the skin.

CASE REPORT

A 73-year-old male developed a lesion on his right cheek in April 2003 compatible with basal cell carcinoma. The re-excision specimen contained a well-differentiated atypical lymphocytic infiltrate consistent with B-CLL along with residual carcinoma. Subsequent laboratory studies revealed peripheral blood lymphocytosis with smudge cells. A diagnosis was made of Rai stage 0 CLL. Chromosomal studies on peripheral blood showed a deletion at 13q14.3. Excision of a second primary skin carcinoma revealed a squamous cell carcinoma in association with B-CLL that was identical to his previously diagnosed skin involvement.

CONCLUSION

This case identifies a cutaneous presentation of subclinical B-CLL. There are two prior reports describing B-CLL presenting initially in the skin. In one case, the infiltrates were incidental on a re-excision specimen. The second report suggests 16% of B-CLL patients have cutaneous manifestations as the first sign of disease.

Bcl-2 regulatory pathway is functional in chronic lymphocytic leukemia

BACKGROUND

Chronic lymphocytic leukemia (CLL) is characterized by accumulation of clonal, malignant CD5(+), CD23(+) B cells. In vivo, these cells have an antiapoptotic phenotype (high levels of Bcl-2 and low levels of proapoptotic Bcl-2 family proteins, such as Bax). Abnormal B cells accumulate due to altered apoptosis regulation rather than to increased proliferation. However, it is unclear whether there are inherent Bcl-2 apoptotic pathway defects. With in vitro culture, these B cells rapidly apoptosis.

METHODS

To investigate apoptosis regulation, Bcl-2, Bax, mitochondrial membrane potential, annexin V, and caspase activation were simultaneous monitored in individual cells during in vitro apoptosis.

RESULTS

With in vitro culture, 30% to 50% of B cells were apoptotic at 24 h compared with fewer than 10% of T cells. Apoptotic B cells showed dramatic Bax upregulation and slight Bcl-2 decreases accompanied by decreased mitochondrial membrane potential and increased activated caspase-3 protein levels. Caspase-3 and caspase-9 activities were increased 18- to 51-fold and 6- to 11-fold, respectively, after 24 h of culture. Caspase-8 showed limited or no activation (less than fourfold).

CONCLUSIONS

These data show that in vitro apoptosis of CLL B cells occurs through a well-characterized Bcl-2 regulatory pathway consistent with that pathway being functional. Further, these cells' antiapoptotic phenotype is dependent on the in vivo environment, potentially involving paracrine/autocrine interactions.

Molecular cytogenetic analysis of B-CLL patients with aggressive disease

We tested a set of commercially available probes to determine the feasibility and accuracy of FISH in the detection of abnormalities in 13 patients with Chronic Lymphocytic Leukemia (CLL) with a particular aggressive clinical disease. We utilized three different probes for the 13q12-14 region, one for the centromeric region of chromosome 12, one for the P53 gene at 17p13.1 and one for 3'-5' IGH at 14q32, covering the entire region of IGH, thus potentially allowing to detect more rearrangements. Conventional cytogenetic study showed a normal karyotype in 8/13 patients. FISH was able to detect chromosomal abnormalities in 10/13 pts (85%): +12 in 4 pts (38%); del 13q in 4 (38%); del 17p in 3 (35%); del of 5'-IGH in 1 (15%). In conclusion FISH confirmed its ability to improve the detection of cytogenetic abnormalities especially in patients with an aggressive disease.

Use of plasma DNA in detection of loss of heterozygosity in patients with multiple myeloma

BACKGROUND

Deletions or structural abnormalities in chromosomes 11 and 13 have been shown to be important in predicting clinical behavior in patients with multiple myeloma (MM). However, cytogenetic analysis in MM is frequently difficult because of poor yield of informative metaphases and the disease is frequently patchy, which complicates fluorescent in situ hybridization studies.

OBJECTIVES

The purpose of this study was to explore the potential of using peripheral plasma DNA for the detection of loss of heterozygosity (LOH) in chromosomes 11 and 13 in patients with MM.

METHODS

Peripheral blood (PB) plasma of 81 patients with MM, was used as a source of DNA for the detection of LOH at chromosomes 13q14 (D13S319 and D13AFMaw301wb5), and 11q21 (D11S2179) using polymerase chain reaction.

RESULTS

Only 62 of the studied patients were informative for the two 13q microsatellite markers and 16 (26%) of these patients showed LOH. Only seven (11%) of 61 patients with informative D11S2179 microsatellite maker showed LOH. Purified plasma cells (PCs) from six bone marrow (BM) samples using anti-CD138-coated magnetic beads showed identical results to those detected in DNA isolated from PB plasma. Three patients with LOH underwent autologous BM transplantation, and two of three reverted to a normal state (no LOH) after transplantation. Seven of the patients with 13q LOH in PB plasma had <10% PCs (PCs) in their BM at the time of testing.

CONCLUSION

PB plasma appears to be enriched by tumor-specific DNA and can be used to detect chromosomal abnormalities in patients with MM. Further studies are needed to establish the clinical relevance of this approach in comparison with other techniques.

The classification of lymphomas: a new beginning or the end of an era?

The World Health Organisation Classification of Tumours of the Haematopoietic and Lymphoid Tissues has recently been published. This is the latest in a long line of classifications of haematological malignancies and will be the international standard. It is now possible to achieve high levels of diagnostic accuracy for the main types of lymphoma. However, many of the entities encompass a wide spectrum of clinical outcomes and this approach to classification may be insufficiently precise for the future needs of haematological oncology. Rapid progress in targeted therapies may require further developments in tumour classification based on pathogenic features rather than arbitrary morphological criteria.

CD38 expression and secondary 17p deletion are important prognostic factors in chronic lymphocytic leukaemia

CD38 expression and chromosomal abnormalities are novel prognostic factors in chronic lymphocytic leukaemia (CLL). However, their value remains undetermined. CD38 was evaluated in 123 patients and chromosomal aberrations in 111 cases with fluorescence in situ hybridization (FISH). CD38 expression was found in 27% of the cases. In addition, seven out of 32 CD38- patients became CD38+ during evolution of the disease. Chromosomal abnormalities included isolated 13q deletion (40%), 12q trisomy (14%), 11q deletion (without 17p deletion) (14%) and 17p deletion (7%). CD38 expression was significantly associated with Binet stages B and C, atypical morphology and 11q deletion. On univariate analysis of survival estimates, advanced Binet stages, CD38+ phenotype, atypical morphology and 11q or 17p deletions were associated with shorter event-free survival (EFS), treatment-free interval (TFI) and overall survival (OS). Multivariate analysis identified both Binet stages and CD38 as independent prognostic factors with regard to EFS and TFI. However, CD38 appeared as an independent factor for OS when restricted to Binet stage A. Chromosomal aberrations were re-evaluated during evolution in 31 cases. The 17p deletion was the most frequent new chromosomal abnormality (35%) and significantly associated with death (64%). In conclusion, CD38 expression and secondary 17p deletion are important poor prognostic indicators, especially in Binet stage A CLL.

Typical and atypical chronic lymphocytic leukemia differ clinically and immunophenotypically

We compared the features of 17 cases of atypical chronic lymphocytic leukemia (aCLL) with those of a clinical control group of 24 cases of CLL. Quantitative flow cytometric data, available for 12 cases, were compared with an immunophenotypic control group of 58 cases using a relative fluorescence indexfor CD5, CD23, CD79b, and surface immunoglobulin light chain (sIg). Compared with the clinical control group, patients with aCLL had a higher mean WBC count and a lower platelet count. Patients with aCLL had a significantly higher probability of disease progression. Compared with an immunophenotypic control group of 58 CLL cases, 12 cases of aCLL demonstrated significantly higher expression of CD23. There was no significant difference in expression of sIg, CD79b, or CD5 between the groups. CD38 expression was noted in only 1 (9%) of 11 tested cases; 2 (18%) of 11 cases had trisomy 12. aCLL can be distinguished from typical CLL morphologically, clinically, and immunophenotypically. Atypical morphologic features in CLL seem to be a marker of aggressive clinical behavior.

Comparative genomic hybridization and amplotyping by arbitrarily primed PCR in stage A B-CLL

Cytogenetic analysis is useful in the diagnosis and to assess prognosis of B-cell chronic lymphocytic leukemia (B-CLL). However, successful cytogenetics by standard techniques has been hindered by the low in vitro mitotic activity of the malignant B-cell population. Fluorescence in situ hybridization (FISH) has become a useful tool, but it does not provide an overall view of the aberrations. To overcome this hurdle, two DNA-based techniques have been tested in the present study: comparative genomic hybridization (CGH) and amplotyping by arbitrarily primed PCR (AP-PCR). Comparative genomic hybridization resolution depends upon the 400-bands of the human standard karyotype. AP-PCR allows detection of allelic losses and gains in tumor cells by PCR fingerprinting, thus its resolution is at the molecular level. Both techniques were performed in 23 patients with stage A B-CLL at diagnosis. The results were compared with FISH. The sensitivity of AP-PCR was greater than CGH (62% vs. 43%). The use of CGH combined with AP-PCR allowed to detect genetic abnormalities in 79% (15/19) of patients in whom G-banding was not informative, providing a global view of the aberrations in a sole experiment. This study shows that combining these two methods with FISH, makes possible a more precise genetic characterization of patients with B-CLL.

Fluorescence in situ hybridization: uses and limitations

The development of molecular hybridization techniques such as fluorescence in situ hybridization (FISH) has had a major Impact on efforts to detect and characterize the genetic changes that give rise to human tumors. With probes designed to Identify specific chromosomes and chromosomal regions, FISH is used routinely by cytogenetics and pathology laboratories to identify recurring chromosomal abnormalities associated with hematologic malignant diseases. In many cases FISH analysis provides increased sensitivity, in that cytogenetic abnormalities have been found In samples that appeared to be normal by morphologic and conventional cytogenetic examination. The combination of cytogenetic, FISH, and molecular analyses provides a powerful approach for diagnosing and subclassifying malignant diseases into clinically and biologically relevant subgroups, In selecting appropriate therapy, and in monitoring the efficacy of therapeutic regimens.

Chronic lymphocytic leukemia

Chronic lymphocytic leukemia continues to attract much basic and clinical research interest. Despite recent advances, the disease still has no established cure. Nonetheless, significant strides have been made in our understanding of the genetics, biology, and clinical staging of this disease. This understanding may improve our ability to segregate patients into subtypes that differ in their cytogenesis, propensity toward disease progression, or response to standard or innovative forms of therapy. Finally, several promising new modalities of treatment are being evaluated in clinical trials, involving novel drugs or drug-combinations, monoclonal antibodies, stem cell transplantation, or gene therapy.