多发性骨髓瘤分子细胞遗传学异常及发病机制：第55届美国血液学会年会报道

分子细胞遗传学异常在多发性骨髓瘤（MM）发病中发挥着重要作用,基于分子细胞遗传学异常的危险因素分层已经被大家所接受并逐渐应用于临床,它已经成为MM最重要的分子标志.并且分子细胞遗传学异常与克隆异质性和克隆进化关系密切,高危细胞遗传学异常患者更容易出现克隆异质性和克隆进化现象.以分子细胞遗传学异常为基础的克隆进化和克隆异质性研究可为进一步认识MM生物学特性及实施个体化治疗奠定基础.     

乳腺癌基因组学研究进展

乳腺癌的发生是由体细胞突变引起。研究乳腺癌的体细胞突变谱有助于明确乳腺癌发生发展的生物学过程。应用二代测序技术对乳腺癌基因组学的研究有了一系列新的认识。二代测序技术检测到新的乳腺癌相关基因, 这些基因的突变频率较低, 不同患者的突变基因却涉及某些通路的失调。某些乳腺癌基因组中可识别特异性突变签名, 但一般不反映环境暴露。尽管所有肿瘤中瘤内异质性均存在亚克隆突变, 均有一个优势克隆占全部乳腺癌细胞的50%以上。乳腺癌基因组学旨在促进向个体化医学转化, 基于基因组信息的乳腺癌分子分型和个体化治疗将在不远的将来成为现实。      

FLT3、NPM1、DNMT3A及IDH基因突变对非M3型急性髓系白血病预后影响的研究进展

非M3型急性髓系白血病(AML)是一组异质性恶性血液系统疾病,无论在形态学、免疫学、细胞遗传学、分子生物学及临床特点上都存在很大差异.细胞遗传学检测结果已经成为AML精确诊断、治疗选择和预后判断的主要依据之一,但由于在分子水平上存在高度的异质性,常规细胞遗传学技术检出率不高.有40%~50%的AML患者在初诊时用标准的染色体显带分析方法检测不到克隆性染色体畸变,被称为正常核型AML.非M3型AML较常见的分子遗传学改变为FLT3、NPM1、DNMT3A、IDH基因突变.文章主要就四种基因的特点、发病机制及对非M3型AML的预后影响作一综述.     

Array comparative genomic hybridization and cytogenetic analysis in pediatric acute leukemias

Most patients with acute lymphocytic leukemia (all) are reported to have acquired chromosomal abnormalities in their leukemic bone marrow cells. Many established chromosome rearrangements have been described, and their associations with specific clinical, biologic, and prognostic features are well defined. However, approximately 30% of pediatric and 50% of adult patients with all do not have cytogenetic abnormalities of clinical significance. Despite significant improvements in outcome for pediatric all, therapy fails in approximately 25% of patients, and these failures often occur unpredictably in patients with a favorable prognosis and "good" cytogenetics at diagnosis.It is well known that karyotype analysis in hematologic malignancies, although genome-wide, is limited because of altered cell kinetics (mitotic rate), a propensity of leukemic blasts to undergo apoptosis in culture, overgrowth by normal cells, and chromosomes of poor quality in the abnormal clone. Array comparative genomic hybridization (acgh-"microarray") has a greatly increased genomic resolution over classical cytogenetics. Cytogenetic microarray, which uses genomic dna, is a powerful tool in the analysis of unbalanced chromosome rearrangements, such as copy number gains and losses, and it is the method of choice when the mitotic index is low and the quality of metaphases is suboptimal. The copy number profile obtained by microarray is often called a "molecular karyotype."In the present study, microarray was applied to 9 retrospective cases of pediatric all either with initial high-risk features or with at least 1 relapse. The conventional karyotype was compared to the "molecular karyotype" to assess abnormalities as interpreted by classical cytogenetics. Not only were previously undetected chromosome losses and gains identified by microarray, but several karyotypes interpreted by classical cytogenetics were shown to be discordant with the microarray results. The complementary use of microarray and conventional cytogenetics would allow for more sensitive, comprehensive, and accurate analysis of the underlying genetic profile, with concomitant improvement in prognosis and treatment, not only for pediatric all, but for neoplastic disorders in general.     

Immunophenotypes in adult acute lymphocytic leukemia. Role of flow cytometry in diagnosis and monitoring of disease

Flow cytometry has revolutionized the study of hematopoietic cells. Immunophenotyping by multiparameter flow cytometry supplements conventional morphologic diagnosis by providing information on cell lineage and differentiation in ALL and helps monitor disease by improving sensitivity in detecting minimal residual disease. The use of multiple MoAbs and multicolor study by flow cytometry has revealed heterogeneity among ALL and mixed-lineage acute leukemia, which are assigned to the same diagnostic categories by morphology. As technology has improved, clinical and research applications of flow cytometry have expanded to include evaluation of nuclear markers, oncogene proteins, apoptosis, cytokine receptors, and drug resistance. Expanded identification of MoAbs against leukemia-specific markers and the use of QFCM be a significant in managing patients with ALL in the future. In addition, flow cytometry and flow cytometric sorting will be combined more and more with other technologies, such as molecular probing or fluorescence in situ hybridization (FISH). The sorting of rare malignant cells based on immunophenotype and subsequent confirmation by PCR or FISH has already been proven feasible. Ultimately, it is hoped that further definition of subgroups of ALL by immunophenotyping using prognostically significant markers and the use of hybrid technologies of flow cytometry and molecular analysis or cytogenetics will improve treatment strategies for patients with ALL.     

Musculoskeletal Oncology: Advances in Cytogenetics and Molecular Genetics and their Clinical Implications

Although musculoskeletal malignancies comprise a small group of cancers, a vast number of histological subtypes have been identified attesting to the heterogeneity of this class of tumours and the growing interest in their development. The mode of management for both bone and soft tissue sarcomas has been examined extensively and treatment guildelines have been proposed. Despite the intensive study and multidisciplinary treatment, a substantial proportion of tumours remain recalcitrant to therapy and recur locally and systemically. Improved methods of characterising these tumours may help in understanding their biology. Cytogenetic and molecular genetic techniques allow a subcellular dissection of these malignancies which may aid the identification of mechanisms that are important in tumorigenesis. Already candidate genes have been isolated which may play an important role in the deregulation of proliferation and/or the adoption of a malignant phenotype, features which are fundamental in tumour development. By studying the molecular biology and cytogenetics of tumours it may be possible to improve diagnostic and prognostic accuracy thereby minimising over and under treatment.     

Potential cure of acute myeloid leukemia : analysis of 1069 consecutive patients in first complete remission

BACKGROUND: Potential cure of acute myeloid leukemia (AML) is now a widely accepted idea, but it is uncertain whether there is heterogeneity in the failure rate in patients once they have been in complete remission (CR) for various periods of time. METHODS: The long-term outcomes were analyzed in 1069 consecutive AML patients in first CR who were diagnosed and treated at the University of Texas M. D. Anderson Cancer Center between 1991 and 2003. RESULTS.: The failure rates as yearly risk of treatment failure were 69.1 in the first year, 37.7 in the second year, 17.0 in the third year, 7.6 in the fourth year, and 6.6 in the fifth year, suggesting that 3 years from the CR date is a convenient time to consider patients potentially cured. The effect of cytogenetics on relapse-free survival (RFS) remained constant throughout the first 3 years, whereas the effect of age increased with time. The probability of RFS for patients alive without disease recurrence at 3 years was 84.0% at 6 years. When the interaction between age and cytogenetics was examined for these patients, the outcomes of those with favorable cytogenetics were found to be excellent regardless of age. However, in the intermediate cytogenetic group, although patients aged <60 years had excellent outcomes, those aged > or =60 years were found to be at a substantial risk of disease recurrence even after 3 years of CR, with a 6-year RFS rate of 56.5%. There were only 6 patients with adverse cytogenetics in this cohort. CONCLUSIONS: The results of the current study demonstrate that the risk of treatment failure differs over time according to a combination of cytogenetics and age.     

Editor's choice: Contemporary murine models in preclinical astrocytoma drug development

Despite 6 decades of research, only 3 drugs have been approved for astrocytomas, the most common malignant primary brain tumors. However, clinical drug development is accelerating with the transition from empirical, cytotoxic therapy to precision, targeted medicine. Preclinical animal model studies are critical for prioritizing drug candidates for clinical development and, ultimately, for their regulatory approval. For decades, only murine models with established tumor cell lines were available for such studies. However, these poorly represent the genomic and biological properties of human astrocytomas, and their preclinical use fails to accurately predict efficacy in clinical trials. Newer models developed over the last 2 decades, including patient-derived xenografts, genetically engineered mice, and genetically engineered cells purified from human brains, more faithfully phenocopy the genomics and biology of human astrocytomas. Harnessing the unique benefits of these models will be required to identify drug targets, define combination therapies that circumvent inherent and acquired resistance mechanisms, and develop molecular biomarkers predictive of drug response and resistance. With increasing recognition of the molecular heterogeneity of astrocytomas, employing multiple, contemporary models in preclinical drug studies promises to increase the efficiency of drug development for specific, molecularly defined subsets of tumors.     

Getting the diagnosis right in NHL: role of immunohistochemistry and molecular diagnostic testing

Challenges in diagnosing lymphoid neoplasms include their complex heterogeneity and the fact that approximately 40 or more diseases exist. Immunophenotyping and molecular diagnostics have made important contributions to precise and accurate diagnoses. Strong interactions with clinical colleagues and meticulous attention at the microscope by expert hematopathologists are important in making a correct diagnosis. Awareness of the literature and interactions with research colleagues, including clinical, basic, and translational scientists, have expanded understanding of these complex diseases, providing prognostic information that can ultimately assist in appropriate clinical management of patients or development of new targeted therapies. This article reviews recent published immunophenotypic diagnostic and biomarker studies, discusses molecular diagnostic expression profiling studies of the more common entities encountered in daily clinical practice, and references published summaries from the combined Society of Hematopathology and European Association for Haematopathology Workshops. A precise lymphoma diagnosis therefore involves integration of clinical information, morphologic architectural and cytologic patterns, immunohistochemistry, cytogenetics, and molecular biology, to ultimately allow identification of specific diseases, thereby implying prognostic significance and potential therapeutic targets.     

Detection of recurrent cytogenetic aberrations in multiple myeloma: A comparison between MLPA and iFISH

Multiple myeloma (MM) is a genetically heterogeneous disease with diverse clinical characteristics and outcomes. Recently, multiplex ligation-dependent probe amplification (MLPA) has emerged as an effective and robust method for the detection of cytogenetic aberrations in MM patients. In the present study, MLPA analysis was applied to analyze cytogenetics of CD138 tumor cells of 59 MM samples, and its result was compared, retrospectively, with the interphase fluorescence in situ hybridization (iFISH) data. We firstly established the normal range of each of the 42 diagnostic probes using healthy donor samples. A total of 151 aberrations were detected in 59 patient samples, and 49/59 cases (83.1%) harbored at least one copy number variation. Overall, 0–7 aberrations were detected per case using MLPA, indicating the heterogeneity and complexity of MM cytogenetics. We showed the high efficiency of MLPA and the high congruency of the two methods to assess cytogenetic aberrations. Considering that MLPA analysis is not reliable when the aberration only exits in a small population of tumor cells, it is essential to use both MLPA and iFISH as complementary techniques for the diagnosis of MM.     

Neuroblastoma: new approaches to diagnosis

Monoclonal antibodies can play an important part in distinguishing neuroblastoma from other small round cell tumours of childhood. In addition, they have been useful in the identification of metastatic tumour cells in bone marrow. Though these roles for antibodies are now well proven, other functions for these reagents such as radioimmunolocalization and targeted therapy need further evaluation. The problems in the diagnostic use of monoclonal antibodies are reviewed and an assessment given on the type of panels that can be constructed as diagnostic aids. Other new diagnostic approaches in vivo and in vitro are reviewed for comparison. The rapidly developing specialties of molecular biology and molecular cytogenetics will almost certainly have an impact on the diagnosis and prognosis of patients with neuroblastoma. Although these are currently research tools, in a short time they will be in use in routine diagnosis. With the increased basic research into neuroblastoma, it is hoped that it will not be too long before the overall survival rate for the disease is improved. In the meantime the new diagnostic approaches outlined in this paper will ensure that patients are treated with an appropriate chemotherapeutic regimen and will allow the selection of subgroups of individuals for new aggressive chemo/radiotherapeutic protocols.     

Emerging prognostic factors in diffuse large B cell lymphoma

PURPOSE OF REVIEW: Diffuse large B cell lymphoma (DLBCL) is the most common lymphoma subtype, characterized by marked clinical and biologic heterogeneity. Gene expression studies together with new monoclonal antibody production are playing an increasing role in determining important prognostic factors/biomarkers predictive of outcome. Despite these technical advances, much confusion exists in the literature as to what constitutes the important biomarkers for determining patient outcome. The purpose of this review is to highlight recent advances in our understanding of novel biomarkers in DLBCL and how these might be incorporated into current risk-adjustment models for prognosis. RECENT FINDINGS: Microarray gene expression analyses have revolutionized our approach to biomarkers in non-Hodgkin lymphomas. Thousands of genes can now be simultaneously analyzed for individual patients, creating a wealth of new data. This has resulted in an improved understanding of the basic biology, as well as the development of new outcome predictors. Monoclonal antibody reagents for some of these biomarkers already exist, allowing for their rapid validation at the level of protein expression and potential clinical translation. SUMMARY: A molecular classification of DLBCL is a current reality, and together with routine morphology, immunophenotype, and molecular cytogenetics, has allowed us to more accurately subclassify DLBCL and determine clinically relevant subgroups. The time is right to begin to consider how these novel biomarkers should be incorporated into current prognostic models to move beyond the clinically based International Prognostic Index     

Remission induction,consolidation and novel agents in development for adults with acute myeloid leukaemia

Chemotherapy regimens used for remission induction in AML have not changed significantly over the last several decades. However the recognition of the prognostic value of cytogenetics and genomics has been a major advance which is helping clarify the most optimal post‐remission consolidation strategy among various risk groups. We are not only beginning to realize the pitfalls of a ‘one‐fits‐all’ approach with intensive, cytarabine‐based chemotherapy as the mainstay, but we are finally beginning to reap the rewards of decades of basic, translational, and clinical research. Developing individualized, ‘targeted’ therapy for each AML patient based on unique molecular features of disease remains a daunting goal yet one that we can now begin to envision. Hypothesis‐based study designs—from pre‐clinical/laboratory experiments to phase‐I and subsequent efficacy trials—provide the foundation for advances in the diagnosis, risk stratification, and treatment for patients with AML. Here we critically review the literature for the management of AML, try to give recommendations regarding the appropriate induction and remission strategy, clarify the role of stem cell transplantation and discuss novel agents on the horizon. Copyright © 2009 John Wiley & Sons, Ltd.     

Targeted antitumour therapy--future perspectives

The advent of targeted therapy presents an unprecedented opportunity for advances in the treatment of cancer. A key challenge will be to translate the undoubted promise of targeted agents into tangible clinical benefits. Achieving this goal is likely to be dependent upon a number of factors. These include continued research to improve our understanding of the heterogeneity and complexity of the tumour microenvironment; refinement of clinical trial design to incorporate nontraditional end points such as the optimum biological dose and health-related quality of life; and the use of technological advancements in proteomics, genomics and biomarker development to better predict tumour types and patient subsets that may be particularly responsive to treatment, as well as enable a more accurate assessment of drug effect at the molecular level. In summary, the future success of targeted agents will require an integrated multidisciplinary approach involving all stakeholders.     

The use of enzyme marker analysis for subclassification of acute lymphocytic leukemia in childhood

Subclassification of acute lymphocytic leukemias in childhood by multiple marker analysis has proven the heterogeneity of this disease and this methodology has led to a better understanding of the cell-biological basis of ALL. Enzyme markers have become important tools in multiple marker analysis. This is especially true for TdT, purine metabolic enzymes, hexosaminidase I, acid phosphatase and carboxylic esterases. In spite of sophisticated methods and encouraging results multiple marker analysis has not been totally satisfactory in defining patients at risk. The same is true for a risk score established by clinical data. More efforts in the future are necessary for combining multiple marker analysis, cytogenetics, proliferation characteristics, basic clinical findings and the final outcome of the disease in these patients. Beyond that this kind of leukemia research will help to clarify the pathobiological basis of human leukemia and to develop new specific therapeutic modalities.     

t(11;14) and t(4;14) translocations correlated with mature lymphoplasmacytoid and immature morphology, respectively, in multiple myeloma.

Recent studies have shown that two recurrent translocations, t(4;14)(p16;q32) and t(11;14)(q13;q32), define distinct entities with different prognosis in multiple myeloma (MM). We addressed the issue of whether these illegitimate IGH rearrangements could contribute to the morphological heterogeneity of the malignant plasma cells (PC). Bone marrow aspirates of 178 untreated MM cases with successful molecular cytogenetics analysis using fluorescence in situ hybridization were reviewed. PC of 25/48 (52%) patients with t(11;14) exhibited a lymphoplasmacytoid morphology. Moreover, 25/27 (93%) of the cases with this morphological profile bore the t(11;14). In addition, both cytogenetics and morphological subtypes shared higher incidence of nonsecretory MM. In contrast, 17 out of 28 cases (61%) with t(4;14) exhibited PC with diffuse chromatin pattern. Interestingly, both t(4;14) translocation and immature morphology correlated with higher incidence of high tumor mass and chromosome 13 abnormality. In conclusion, our results suggest that a particular morphology can be the signature of chromosomal abnormalities in MM.     

Pediatric oncology enters an era of precision medicine

With the use of high-throughput molecular profiling technologies, precision medicine trials are ongoing for adults with cancer. Similarly, there is an interest in how these techniques can be applied to tumors in children and adolescents to expand our understanding of the biology of pediatric cancers and evaluate the clinical implications of genomic testing for these patients. This article reviews the early studies in pediatric oncology showing the feasibility of this approach, describe the future plans to evaluate the clinical implications in a multicenter clinical trial and identify the challenges of applying genomics in this patient population.