Cytogenetic profiles in multiple myeloma and monoclonal gammopathy of undetermined significance: a study in highly purified aberrant plasma cells

This is an open-access paper.Cytogenetic studies in clonal plasma cell disorders have mainly been done in whole bone marrow or CD138+ microbead-enriched plasma cells and suggest that recurrent immunoglobulin heavy chain translocations - e.g. t(4;14) - are primary oncogenetic events. The aim of this study was to determine cytogenetic patterns of highly purified aberrant plasma cells (median purity ≥98%) in different clonal plasma cell disorders. We analyzed aberrant plasma cells from 208 patients with multiple myeloma (n=148) and monoclonal gammopathy of undetermined significance (n=60) for the presence of del(13q14), del(17p13) and t(14q32) using multicolor interphase fluorescence in situ hybridization. Additionally, immunoglobulin heavy chain gene arrangements were analyzed and complementarity determining region 3 was sequenced in a subset of patients and combined multicolor interphase fluorescence in situ hybridization/immunofluorescent protein staining analyses were performed in selected cases to confirm clonality and cytogenetic findings. At diagnosis, 96% of cases with multiple myeloma versus 77% of monoclonal gammopathy of undetermined significance cases showed at least one cytogenetic alteration and/or hyperdiploidy. The cytogenetic heterogeneity of individual cases reflected coexistence of cytogenetically-defined aberrant plasma cell clones, and led to the assumption that karyotypic alterations were acquired stepwise. Cases of multiple myeloma and monoclonal gammopathy of undetermined significance frequently showed different but related cytogenetic profiles when other cytogenetic alterations such as deletions/gains of the immunoglobulin heavy chain or the fibroblast growth factor receptor 3 were additionally considered. Interestingly, in 24% of multiple myeloma versus 62% of monoclonal gammopathy of undetermined significance patients with an immunoglobulin heavy chain translocation, aberrant plasma cells with and without t(14q32) coexisted in the same patient. Our data suggest that recurrent immunoglobulin heavy chain translocations might be absent in the primordial plasma cell clone in a significant proportion of patients with clonal plasma cell disorders carrying these cytogenetic alterations.This work was partially supported by grants from the Fundacion Memoria de Don Samuel Solorzano Barruso, Salamanca, Spain (FS/4-2010). The authors would also like to thank the Dr. Werner Jackstädt Foundation (Wuppertal, Germany) for grant supporting the work of Martin Schmidt-Hieber. The authors would like to thank the Cooperative Research Thematic Network (RTICs; RTICC RD06/0020/0035, RD06/0020/0006 and G03/136), MM Jevitt, SL firm, Instituto de Salud Carlos III/Subdirección General de Investigación Sanitaria (FIS: PI060339; 02/0905; 01/0089/01-02; PS09/01897) and Gerencia Regional de Salud de Castilla y León; Ayuda de Excelencia de Castilla y León, Consejeria de Educación (EDU/894/2009, GR37), and Consejería de Sanidad (557/A/10), Junta de Castilla y León, Valladolid, Spain for supporting this study. JMS is supported by a grant (CP05/00321) from the ISCIII, Ministerio de Ciencia e Innovacion, Madrid, Spain.Peer Reviewe

Genetic stability of human embryonic stem cells: A first-step toward the development of potential hESC-based systems for modeling childhood leukemia

Human ESCs provide an opportunity for modeling human-specific strategies to study the earliest events leading to normal hematopoietic specification versus leukemic transformation. Of interest, are the human childhood acute leukemias harboring specific fusion oncogenes such as MLL-AF4, TEL-AML1 or BCR-ABL wherein clinically significant manifestations arise in utero. The mechanisms of transformation are not amenable to analysis with patient samples and, many mouse models for pediatric leukemias have fallen short in illuminating the human disease because they do not recapitulate key aspects of the actual disease, suggesting that the mouse models are missing essential components of oncogenesis present in the human embryo. Prior to using hESCs as a tentative system for modeling leukemia, robust studies aimed at demonstrating their genetic stability are required; otherwise, cooperating mutations already present could prime hESCs susceptible to transformation. We performed an extensive molecular cytogenetic and cellular in vitro and in vivo analysis which reveals an overall genomic stability of HS181 and HS293 hESCs maintained long-term by mechanical dissociation in human feeders. Importantly, we show for the first time that the genetically stable HS181 hESC line differentiates into CD45+ hematopoietic cells and clonogenic hematopoietic progenitors. This data should encourage stem cell researchers to implement robust cytogenetic tools when assessing hESC genetic stability, in order to detect tiny but relevant biological functional or structural chromosome abnormalities and, paves the way for generating fusion oncogene-expressing transgenic hESCs as a human-specific system for studying the early in utero events leading to normal hematopoietic specification versus childhood leukemic transformation. © 2008 Elsevier Ltd. All rights reserved.This work was funded by the Andalusian Health Government (refs: 0028, 0029 and, 0030/2006 to PM), The International Jose Carreras Foundation against the Leukemia to PM/CB (EDThomas-05), The UK Leukemia Research Fund to MG/PM (06039) and, the Spanish Ministry of Health to PM (FIS PI070026) and CB (CP07/00059).Peer Reviewe

Impact of trisomy 12, del(13q), del(17p), and del(11q) on the immunophenotype, DNA ploidy status, and proliferative rate of leukemic B-cells in chronic lymphocytic leukemia

B-cell chronic lymphocytic leukemia (B-CLL) is a well-defined clinical entity with heterogeneous molecular and cytogenetic features. Here, we analyze the impact of trisomy 12, del(13q), del(17p), and del(11q) as determined by interphase fluorescence in situ hybridization analysis of purified neoplastic B-CLL cells on their immunophenotype , DNA ploidy status and proliferative rate. Overall, 111 of 180 (62%) B-CLL cases studied displayed one (50%) or more (12%) genetic abnormalities, del(13q) (35%) being more frequently detected than trisomy 12 (23%) followed by del(11q) (9%) and del(17p) (8%). Trisomy 12 was associated with a higher frequency of DNA aneuploidy, stronger expression of CD19, CD20, CD22, CD24, CD27, CD79b, CD38, and slg and lower reactivity for CD43 with respect to cytogenetically nonaltered cases. In turn, cases with del(13q) displayed greater reactivity for CD20, FMC7, CD27, CD22, CD5, and bcl2, while del(11q) was associated with brighter expression of CD38, FMC7, CD25, and slg. Hierarchical clustering analysis of the immunophenotype of B-CLL cases with cytogenetic abnormalities allowed the identification of three different groups of patients with increasing frequencies of trisomy 12, del(11q), and del(13q). Remarkably, none of the cytogenetic abnormalities analyzed except coexistence of 13q- and 17p- had a clear impact on the proliferative index of B-CLL cells. © 2007 Clinical Cytometry Society.Ministerio de Sanidad y Consumo, Madrid, Spain; Grant number: CP05/00321; Grant sponsor: COLCIENCIAS Bogotá, Colombia.Peer Reviewe

Utility of flow cytometry immunophenotyping in multiple myeloma and other clonal plasma cell-related disorders

In recent years, multiparameter flow cytometry (MFC) immunophenotyping has become mandatory in the clinical management of hematological malignancies, both for diagnostic and monitoring purposes. Multiple myeloma (MM) and other clonal plasma cell-related (PC) disorders should be no exception to this paradigm, but incorporation of immunophenotypic studies in the management of patients with PC disorders is still far from being routinely established in many diagnostic flow cytometry laboratories. For clonal PC disorders, MFC is of clear and established clinical relevance in: (1) the differential diagnosis between MM and other PC-related disorders; (2) the identification of high-risk MGUS and smoldering MM; (3) minimal residual disease investigation after therapy; additionally it may also be useful for (4) the definition of prognosis-associated antigenic profiles; and (5) the identification of new therapeutic targets. In this article, we review the clinical value of MFC in the study of PC disorders, with specific emphasis in those areas where consensus exists on the need to incorporate MFC into routine evaluation of MM and other clonal PC-related disorders.Peer Reviewe

Flow cytometry immunophenotyping of fine-needle aspiration specimens: Utility in the diagnosis and classification of non-Hodgkin lymphomas

[Aims]: To establish the utility of flow cytometry (FCM) for screening and diagnosis of B cell non-Hodgkin lymphoma (B-NHL) from lymphoid tissue samples obtained by fine-needle aspiration (FNA). [Methods and results]: We compared prospectively FCM versus cytology/histology analysis of FNA samples for the diagnostic screening and further World Health Organization (WHO) subclassification of B-NHL. FCM and cytology showed a high degree of agreement (93%); however, diagnosis of reactive processes (RP), B-NHL and T-NHL by FCM showed higher sensitivity than cytology (92-100% versus 64-94%, respectively), without false positive NHL cases. The antibody combination used did not allow a positive diagnosis of Hodgkin lymphoma as distinct from a RP. A high concordance rate was found between FCM and histopathology (74%) in subtyping B-NHL. In this regard, mantle-cell lymphoma and chronic lymphocytic leukaemia/small lymphocytic lymphoma showed the highest degree of agreement (100% concordant rates). In turn, FCM showed higher sensitivity/specificity in classifying follicular lymphoma (FL) and large B cell lymphomas, while the opposite occurred for marginal-zone and lymphoplasmacytic lymphomas. [Conclusions]: FCM enhances the diagnostic ability of FNA cytology, playing a crucial role in a rapid and accurate differential diagnosis between RP, B-NHL and T-NHL. In addition, immunophenotyping of FNA samples contributes to a more precise subclassification of B-NHL when combined with histopathology and genetic/molecular data. © 2011 Blackwell Publishing Limited.This work has been supported partially by the RTICC RD06 ⁄ 0020 ⁄ 0035-FEDER, and FIS 08 ⁄ 90881 grants, from the Fondo de Investigación Sanitaria, Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación, Madrid, Spain. JM Sayagués is supported by CP05 ⁄ 00321 grant, from the Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación, Madrid, Spain.Peer Reviewe

The Progression from MGUS to Smoldering Myeloma and Eventually to Multiple Myeloma Involves a Clonal Expansion of Genetically Abnormal Plasma Cells

[Purpose]: Genetic aberrations detected in multiple myeloma (MM) have also been reported in the premalignant conditions monoclonal gammopathy of undetermined significance (MGUS) and smoldering MM (SMM). Our aim was to investigate in depth the level of clonal heterogeneity of recurrent genetic abnormalities in these conditions. [Experimental Design]: Immunoglobulin heavy chain (IGH) translocations, 13q14 and 17p13 deletions, and 1q21 gains using FISH were evaluated in 90 MGUS, 102 high-risk SMM, and 373 MM. To this end, we not only purified plasma cells (PC) for the FISH analysis (purity > 90%), but subsequently, we examined the correlation between the proportion of PC with cytogenetic changes and the number of clonal PC present in the same sample, as measured by multiparametric flow cytometry. [Results]: We observed a significant difference between the proportion of clonal PC with specific genetic abnormalities in MGUS compared with SMM and in SMM compared with MM. Thus, the median proportion of PC with IGH translocations globally considered, t(11;14) and 13q deletions was significantly lower in MGUS than in SMM, and in SMM than in MM [IGH translocations: 34% vs. 57% vs. 76%; t(11;14): 38% vs. 61% vs. 81%; and 13q deletion: 37% vs. 61% vs. 74% in MGUS, SMM, and MM, respectively]. For t(4;14), the difference was significant in the comparison between MGUS/SMM and MM and for 1q between MGUS and SMM/MM. [Conclusions]: This study demonstrates that the progression from MGUS to SMM, and eventually to MM, involves a clonal expansion of genetically abnormal PC. ©2011 AACR.This study was partially supported by Spanish FIS (PI080568) and >Junta de Castilla y León> (140/A/07, GRS202/A08) grants, and the Spanish Myeloma Network Program (RD06/0020/0006).Peer Reviewe

The immunophenotype of different immature, myeloid and B-cell lineage-committed CD34+ hematopoietic cells allows discrimination between normal/reactive and myelodysplastic syndrome precursorsCD34+ cells phenotype in myelodysplastic syndromes

Occurrence of phenotypic abnormalities in CD34+ hematopoietic progenitor and precursor cells (HPC) and their major B-cell and nonlymphoid compartments has been frequently reported in myelodysplastic syndromes (MDS). Here, we analyze for the first time the numerical and phenotypic abnormalities of different maturation-associated subsets of bone marrow (BM) CD34+ HPC from 50 newly diagnosed MDS patients in comparison to normal/reactive BM (n=29). Our results confirm the existence of heterogeneously altered phenotypes among CD34+ HPC from MDS and indicate that such variability depends both on the relative distribution of the different subsets of CD34+ HPC committed into the different myeloid and B-lymphoid compartments, and their immunophenotype (for example, higher reactivity for CD117 and CD13 and lower expression of CyMPO, CD64 and CD65 on CD34+ immature and neutrophil precursors), a clear association existing between the accumulation of CD34+ HPC and that of immature CD34+ HPC. Interestingly, expansion of erythroid- and neutrophil-lineage CD34+ cells is detected in low-grade MDS at the expense of CD34+ plasmacytoid dendritic cell and B-cell precursors, while expansion of immature CD34+ precursors occurs in high-grade MDS. On the basis of the number and severity of the phenotypic abnormalities detected, a scoring system is proposed that efficiently discriminates between normal/reactive and MDS CD34+ HPC, the mean score significantly increasing from low- to high-grade MDS.Peer Reviewe

Bone marrow cells from myelodysplastic syndromes show altered immunophenotypic profiles that may contribute to the diagnosis and prognostic stratification of the disease: A pilot study on a series of 56 patients

A heterogeneous spectrum of immunophenotypic abnormalities have been reported in myelodysplastic syndromes (MDS). However, most studies are restricted to the analysis of CD34+ cells and/or other major subsets of CD34- cells, frequently not exploring the diagnostic and prognostic impact of immunophenotyping. Methods: We propose for the first time an immunophenotypic score (IS) based on the altered distribution and immunophenotypic features of maturing/mature compartments of bone marrow (BM) hematopoietic cells in 56 patients with MDS that could contribute to a refined diagnosis and prognostic evaluation of the disease. Results: Although MDS-associated phenotypes were detected in reactive BM, the overall immunophenotypic profile of BM cells allowed an efficient discrimination between MDS and both normal and reactive BM, once the number and degree of severity of the abnormalities detected per patient were simultaneously considered in the proposed IS. Interestingly, increasingly higher IS were found among patients with MDS showing adverse prognostic factors and in low- versus high-grade cases. The most informative prognostic factors included the number of CD34+ cells, presence of aberrant CD34-/CD117+ precursors, decreased mature neutrophils and CD34- erythroid precursors, and increased numbers of CD361/lo erythroid precursors; in addition, the IS was an independent prognostic factor for overall survival. Conclusions: Assessment of immunophenotypic abnormalities of maturing/mature BM cells allows an efficient discrimination between MDS and both normal and reactive BM, once the number and degree of severity of the abnormalities detected are simultaneously scored. Interestingly, progressively higher IS were found among patients with MDS with adverse prognostic features and shorter overall survival. © 2010 Clinical Cytometry Society.Instituto de Salud Carlos III, Ministerio de Sanidad y Consumo, Madrid, Spain; Grant number: RTICC RD06/0020/0035; Ministerio de Sanidad Consumo Grant number: CP05/003 (to J.M.S.); Fundaçao para a Ciencia e a Tecnologia (FCT), Portugal; SFRH/BD/32097/2006 (to P.L.).Peer Reviewe

Association between the proliferative rate of neoplastic B cells, their maturation stage, and underlying cytogenetic abnormalities in B-cell chronic lymphoproliferative disorders: Analysis of a series of 432 patients

Trabajo presentado al "13th Congress of the European Hematology Association" celebrado en Copenhague en Junio del 2008.-- et al.Limited knowledge exists about the impact of specific genetic abnormalities on the proliferation of neoplastic B cells from chronic lymphoproliferative disorders (B- CLPDs). Here we analyze the impact of cytogenetic abnormalities on the proliferation of neoplastic B cells in 432 B-CLPD patients, grouped according to diagnosis and site of sampling, versus their normal counterparts. Overall, proliferation of neoplastic B cells highly varied among the different B-CLPD subtypes, the greatest numbers of proliferating cells being identified in diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma (BL). Compared with normal B cells, neoplastic B-CLPD cells showed significantly increased S + G2/M-phase values in mantle cell lymphoma (MCL), B-chronic lymphocytic leukemia (B-CLL), BL, and some DLBCL cases. Conversely, decreased proliferation was observed in follicular lymphoma, lymphoplasmacytic lymphoma/ Waldenstrom macroglobulinemia (LPL/ WM), and some DLBCL patients; hairy cell leukemia, splenic marginal zone, and MALT-lymphoma patients showed S + G 2/ M phase values similar to normal mature B lymphocytes from LN. Interestingly, in B-CLL and MCL significantly higher percentages of S + G 2/M cells were detected in BM versus PB and in LN versus BM and PB samples, respectively. In turn, presence of 14q32.3 gene rearrangements and DNA aneuploidy, was associated with a higher percentage of S + G2/M-phase cells among LPL/WM and B-CLL cases, respectively. © 2008 by The American Society of Hematology.This work has been partially supported by the following grants: FIS 06/0824, from the Ministerio de Sanidad y Consumo (Madrid, Spain) and RETICC RD06/0020/0035 from the Instituto de Salud Carlos III, Ministerio de Sanidad y Consumo (Madrid, Spain). S.Q. is supported by a grant from COLCIENCIAS (Bogotá, Colombia), J.M.S. is supported by a grant from the Ministerio de Sanidad y Consumo (Madrid, Spain; CP05/ 00321), A.R. is supported by a grant from the Ministerio de Ciencia y Tecnología (Madrid, Spain) y Fondo Social Europeo, and C.F. is supported by a grant from the Instituto de Salud Carlos III (Madrid, Spain; CM05/00250).Peer Reviewe