MicroRNA in chronic lymphocytic leukemia: transitioning from laboratory-based investigation to clinical application

Chronic lymphocytic leukemia (CLL) is the most common form of leukemia among adults in the Western world, with an incidence of approximately 1 out of 100,000 patients per year. CLL is characterized by the clonal expansion of immature CD5⁺ B cells. Although cytotoxic agents remain the mainstay of therapy, the disease of up to 20% of patients is not controlled with standard therapies. Therefore, there remains a need for novel therapeutic strategies. MicroRNAs (miRNAs or miRs), first identified nearly two decades ago, are noncoding RNAs that have the capacity for simultaneous regulation of tens to hundreds of genes. An association between CLL-associated chromosomal abnormalities and miRNA deregulation is beginning to emerge. miRNAs may play a biological role in the pathogenesis of CLL: specific miRNAs (miR-15a and miR-16-1) are located at a chromosomal region (13q14.3) that is often absent in patients with CLL. These same miRNAs are relevant to cellular phenotype and in vivo development of disease. This finding has led to a rapidly expanding series of investigations linking miRNAs to CLL. As a result, miRNAs are currently under investigation as diagnostic and prognostic biomarkers as well as potential therapeutic targets in CLL.     

Monoclonal antibody associated with a lymphocyte subpopulation in chronic lymphocytic leukemia

An IgG monoclonal antibody that detects a subpopulation of lymphocytes found in peripheral blood and bone marrow of patients with CLL and malignant lymphoma is described. The initial immunization used to achieve the resultant monoclonal antibody included the use of cells obtained by DNA transformation of mouse L-cells with the DNA obtained from a morphologically altered somatic cell hybrid between primary human CLL peripheral lymphocytes and a flat-revertant Chinese hamster ovary (CHO) cell line designated GRC+L-73. Hybridomas were thus selected as potentially recognizing antigens associated with the morphological transformation induced by hybridization of CHO cells with lymphocytes from lymphocytic malignancies. One such hybridoma, designated 37-28, was selected for further investigation. The monoclonal antibody produced was IgG (gamma G2a) and detects a subpopulation of lymphocytes present in hematological specimens of some of the lymphocytic malignancies.     

A putative "hepitype" in the ATM gene associated with chronic lymphocytic leukemia risk

Chronic lymphocytic leukemia (CLL) cells are characterized by several chromosomal lesions. Some of these aberrations imply chromosome breaks as a result of unrepaired double strand breaks (DSBs) in the DNA. The ATM (ataxia telangiectasia-mutated) protein is the principal integrator of cellular responses to DSBs. ATM deletion is also an adverse prognostic factor in CLL. Taking this into account, we evaluated if genetic and/or epigenetic variation in the ATM gene may modulate the individual susceptibility to develop CLL. Our case-control association study was performed in a large Spanish population of 1,503 individuals, including 742 patients with CLL and 761 controls. We identified one haplotype within the ATM gene that confers an increased risk of CLL development (OR = 1.33; 95% CI: 1.10-1.60). Two polymorphisms of this ATM haplotype eliminated one CpG site each in Introns 15 and 61, causing changes in DNA methylation pattern. These data provide the first evidence for the existence of a putative "hepitype" in the ATM gene associated with CLL risk.     

Ocular melanoma associated with lymphocytic leukemia

A rare combination of ocular melanoma with chronic myeloid leukemia was registered in a 61-year-old woman. The case history was not properly assessed in due time, therefore, the reason of ophthalmectomy was not identified leading to misdiagnosis. Neither chemotherapy nor radiation treatment was administered that permitted the author to establish a metachronous character of the primary malignancies. Melanoma was also uncommon for spindle cell components prone to late dissemination, specific alveoli resembling nevoid structures. There were metastases to the spleen.     

Biclonal chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is well characterized clinically and immunophenotypically. Demonstration of a monotypic CD19+, CD5+ B-cell population is central to the diagnosis. We report 2 cases of biclonal CLL. Two elderly men were encountered with an absolute lymphocytosis consisting of the typical CD5+, CD19+, CD23+ B-cell population seen in CLL; however, immunoglobulin light chain restriction by flow cytometry was not apparent as B cells expressed kappa or lambda light chains without a clear monotypic population. Molecular genetic analysis of flow cytometry-sorted cells (kappa and lambda populations) revealed in both cases 2 monoclonal B-cell populations. The characterization of these cases and a review of the issues surrounding biclonal CLL are presented.     

B-cell function in patients with chronic lymphocytic leukemia

Summary Using a reverse hemolytic protein A plaque assay, spontaneous and pokeweed mitogen (PWM)-induced immunoglobulin (Ig) secretion was determined in peripheral blood from 22 patients with B₁-chronic lymphocytic leukemia (CLL), one patient with B₂-CLL, and one patient with suppressor T-CLL. Diagnoses were established by cytological and histological criteria as well as several marker analyses. Lymphocytes from B₁- and B₂-CLL patients were unable to secrete Ig either spontaneously or after PWM stimulation. In T-CLL lymphocytes, spontaneous Ig secretion was suppressed very probably by the OKT-8-positive leukemic population, since, after cultivation with PWM, a normal Ig secretion could be demonstrated which was paralleled by a decrease in the OKT-8-positive cells. Cocultivation experiments with freshly isolated, unseparated lymphocytes from normal subjects and lymphocytes from patients were of no informational value, since isolated normal B-cells alone already showed a high rate of Ig secretion. However, coculture experiments with separated subpopulations after PWM stimulation revealed an intrinsic B-cell defect in lymphocytes from B₁-CLL patients, whereas their T-lymphocytes were found to be normal helper cells.

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Abbreviations CLL Chronic lymphocytic leukemia - PWM Pokeweed mitogen - ISC Immunoglobulin-secreting cells - Ig Immunoglobulin(s) Supported by the Deutsche Forschungsgemeinschaft (Ru 215/2)     

A translocation breakpoint at chromosome band 12q13 associated with B-cell chronic lymphocytic leukemia.

Low-grade B-cell lymphoproliferative disorders are frequently associated with an extra copy of chromosome 12. This well-documented acquired anomaly is one of the most specific numerical chromosome alterations to occur in human hematological malignancies. We have cytogenetically characterized bone marrow and peripheral blood cells from a patient with B-cell chronic lymphocytic leukemia (CLL) having a unique acquired translocation involving chromosomes 6 and 12, t(6;12) (p21.3;q13), which implicates band 12q13 as the site of the gene(s) important in this lymphoproliferative B-cell disorder. Aneuploidy, in the form of trisomy of chromosome 12, is not a requirement for neoplastic transformation in B-cell CLL, but gene rearrangement (present case) or nondisjunctional acquisition of additional copies of defective genes on chromosome 12 at band q13 may be involved in the genesis or progression of this disorder.     

Genomic profile of chronic myelogenous leukemia: Imbalances associated with disease progression

The expression of the chimeric BCR/ABL1 fusion gene resulting from t(9;22)(q34;q11) in chronic myelogenous leukemia (CML) is necessary for malignant transformation, but not sufficient to maintain disease progression. The appearance of various chromosomal and molecular alterations in the accelerated and terminal phase of CML is well documented, but evidence for causal relationship is largely lacking. We carried out a genome wide screening at a resolution of 1 Mb of 54 samples at different stages of CML together with 12 CML cell lines and found that disease progression is accompanied by a spectrum of recurrent genome imbalances. Among the most frequent are losses at 1p36, 5q21, 9p21, and 9q34 and gains at 1q, 8q24, 9q34, 16p, and 22q11, all of which were located with higher precision within the genome than previously possible. These genome imbalances are unique to CML cases with clinically manifested or suspected accelerated/blast stage alike, but not seen in chronic phase samples. Previously unrecognized cryptic imbalances occurring within the Ph-chromosome were also detected, although further scrutiny is required to pin-point gene involvement and seek association with disease features. Importantly, some of these imbalances were seen in the CD34(+) cells but not in the whole BM samples of patients in accelerated phase. Taken together, these findings highlight the potential of screening CD34(+) cells for genome wide imbalances associated with disease progression. Finally, the numerous single copy number variations recorded, many unique to this cohort of patients, raise the possible association of genome polymorphism and CML.     

Protein synthesis in the blood lymphocytes of chronic lymphocytic leukemia and its relationship to prognosis

Summary Protein synthesis primed by endogenous messenger RNA (mRNA) as well as polyuridylic acid-[poly (U)] directed polyphenylalanin synthesis was measured in extracts of blood lymphocytes from a series of 50 chronic lymphocytic leukemia (CLL) patients and compared with the prognostic stage. Patients were clinically classified according to the new international workshop classification [4]. There were 23 patients at stage A, 14 at stage B and 13 at stage C. Extracts from patients of the high risk group (stage C), defined by anemia and/or thrombocytopenia, exhibited a significantly higher poly (U)-translation activity than extracts from low and intermediate risk patients-stages A and B–(P<0.01). This finding has a sensitivity of 62% but a specifity of 100%. During follow-up, an increase of poly (U)-translation and endogenous protein synthesis was observed after changing from stages A or B to stage C. Activity of protein synthesis could neither be correlated with proliferation activity, as measured by lymphocyte doubling time, nor with the expression of immunologic surface markers, nor with serum immunoglobuline (Ig) levels.

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Abbreviations Ig immunoglobuline - S-Ig surface immunoglobuline - Fc-R receptor for the Fc part of Ig - E_mouse receptor for mouse erythrocytes - poly (U) polyuridylic acid - mRNA messenger RNA - CLL chronic lymphocytic leukemia This work was supported by the Deutsche Forschungsgemeinschaft, Grant Em 20/4     

Lung biopsy in chronic lymphocytic leukemia

Nine patients with chronic lymphocytic leukemia (CLL), with pulmonary involvement confirmed by biopsy, presented with progressive cough and/or shortness of breath and had interstitial infiltrates on chest radiographs. Biopsies showed a dense lymphocytic infiltrate that followed bronchovascular bundles. We considered CLL the predominant finding, and the cause of the patient's pulmonary disease, in eight cases; in one, a histologically nonspecific organizing pneumonia was the main lesion and CLL was an incidental finding. Culture results were available in six cases and were negative except in one case with presumed contaminants. A granulomatous reaction was present in five cases and was necrotizing in two, although culture results were negative. The only case with a recognizable organism had noninvasive fungal hyphae growing in many of the small airways. All of the patients' respiratory symptoms improved after chemotherapy and/or steroid therapy, and the chest radiographs also showed clearing.     

慢性淋巴细胞白血病8号染色体三体异常的研究

论 +8异常在CLL群体中少见,其与预后关系暂不明确.     

HLA antigens in chronic lymphocytic leukemia

HLA-A, B, and C phenotypes of 88 white and 14 black patients with chronic lymphocytic leukemia (CLL) were compared with those of 3761 white and 660 black laboratory population controls, and HLA-DR phenotypes were compared with 742 white and 236 black controls from the same population. Several statistically significant associations were found, one of which (a strongly positive association with Cw6 for whites) persisted after correction for the number of antigens tested.