Genetics in myeloma: genetic technologies and their application to screening approaches in myeloma

Non-invasive prenatal test identifies circulating cell-free DNA chromosomal abnormalities derived from clonal hematopoiesis in aggressive hematological malignancies

Liquid biopsy is a minimally invasive diagnostic tool for identification of tumor-related mutations in circulating cell-free DNA (cfDNA). The aim of this study was to investigate feasibility, sensitivity, and specificity of non-invasive prenatal test (NIPT) for identification of chromosomal abnormalities in cfDNA from a total of 77 consecutive patients with non-Hodgkin B-cell lymphomas, Hodgkin lymphoma (HL), or plasma cell dyscrasia. In this case series, half of patients had at least one alteration, more frequently in chromosome 6 (23.1%), chromosome 9 (20.5%), and chromosomes 3 and 18 (16.7%), with losses of chromosome 6 and gains of chromosome 7 negatively impacting on overall survival (OS), with a 5-year OS of 26.9% and a median OS of 14.6 months, respectively (P = 0.0009 and P = 0.0004). Moreover, B-cell lymphomas had the highest NIPT positivity, especially those with aggressive lymphomas, while patients with plasma cell dyscrasia with extramedullary disease had a higher NIPT positivity compared to conventional cytogenetics analysis and a worse outcome. Therefore, we proposed a NIPT-based liquid biopsy a complementary minimally invasive tool for chromosomal abnormality detection in hematological malignancies. However, prospective studies on larger cohorts are needed to validate clinical utility of NIPT-based liquid biopsy in routinely clinical practice.

Melt-Encoded-Tags for Expanded Optical Readout in Digital PCR (METEOR-dPCR) Enables Highly Multiplexed Quantitative Gene Panel Profiling

Digital PCR (dPCR) is an important tool for precise nucleic acid quantification in clinical setting, but the limited multiplexing capability restricts its applications for quantitative gene panel profiling. Here, this work describes melt-encoded-tags for expanded optical readout in digital PCR (METEOR-dPCR), a simple two-step assay that enables simultaneous quantification of a large panel of arbitrary genes in a dPCR platform. Target genes are quantitatively converted into DNA tags with unique melting temperatures through a ligation approach. These tags are then counted and distinguished by their melt-curve profiles on a dPCR platform. A multiplexing capacity of M^N, where M is the number of resolvable melting temperature and N is the number of fluorescence channel, can be achieved. This work validates METEOR-dPCR with simultaneous DNA copy number profiling of 60 targets using dPCR in cancer cells, and demonstrates its sensitivity for estimating tumor fraction in mixed tumor and normal DNA samples. The rapid, quantitative, and highly multiplexed METEOR-dPCR assay will have wide appeal for many clinical applications.

Artificial Intelligence in Plasma Cell Myeloma: Neural Networks and Support Vector Machines in the Classification of Plasma Cell Myeloma Data at Diagnosis

Background:

Plasma cell neoplasm and/or plasma cell myeloma (PCM) is a mature B-cell lymphoproliferative neoplasm of plasma cells that secrete a single homogeneous immunoglobulin called paraprotein or M-protein. Plasma cells accumulate in the bone marrow (BM) leading to bone destruction and BM failure. Diagnosis of PCM is based on clinical, radiologic, and pathological characteristics. The percent of plasma cells by manual differential (bone marrow morphology), the white blood cell (WBC) count, cytogenetics, fluorescence in situ hybridization (FISH), microarray, and next-generation sequencing of BM are used in the risk stratification of newly diagnosed PCM patients. The genetics of PCM is highly complex and heterogeneous with several genetic subtypes that have different clinical outcomes. National Comprehensive Cancer Network guidelines recommend targeted FISH analysis of plasma cells with specific DNA probes to detect genetic abnormalities for the staging of PCM (4.2021). Recognition of risk categories through training software for classification of high-risk PCM and a novel way of addressing the current approaches through bioinformatics will be a significant step toward automation of PCM analysis.

Methods:

A new artificial neural network (ANN) classification model was developed and tested in Python programming language with a first data set of 301 cases and a second data set of 176 cases for a total of 477 cases of PCM at diagnosis. Classification model was also developed with support vector machines (SVM) algorithm in R studio and interactive data visuals using Tableau.

Results:

The resulting ANN algorithm had 94% accuracy for the first and second data sets with a classification summary of precision (PPV): 0.97, recall (sensitivity): 0.76, f1 score: 0.83, and accuracy of logistic regression of 1.0. SVM of plasma cells versus TP53 revealed a 95% accuracy level.

Conclusion:

A novel classification model based only on specific morphological and genetic variables was developed using a machine learning algorithm, the ANN. ANN identified an association of WBC and BM plasma cell percentage with two of the high-risk genetic categories in the diagnostic cases of PCM. With further training and testing of additional data sets that include morphologic and additional genetic rearrangements, the newly developed ANN model has the potential to develop an accurate classification of high-risk categories of PCM.

Smoldering multiple myeloma - Past, present, and future

Smoldering multiple myeloma (SMM) routinely precedes the development of multiple myeloma. While some patients experience aggressive disease, others have more indolent courses akin to those with monoclonal gammopathy of undetermined significance. Much effort has been made to understand the pathobiological basis of this heterogeneity. Scientific advancements have led to the emergence of various clinical and genomic markers of relevance, translating into evolution of disease definitions over time. More recently, the interest in manipulation of biological pathways has intensified in a bid to stall or halt disease progression. Studies with lenalidomide have exemplified the promise of early intervention, whereas numerous therapeutic approaches remain the subject of ongoing clinical investigation. This review summarizes the historic progress made in defining SMM as a distinct clinicopathologic entity, provides a critical appraisal of the evidence guiding risk assessment, and suggests a pragmatic approach to its modern-day management. Finally, an overview of developments on the horizon is also provided.

Pros and Cons for Fluorescent in Situ Hybridization, Karyotyping and Next Generation Sequencing for Diagnosis and Follow-up of Multiple Myeloma

Multiple myeloma (MM) is one of the plasma cell-related hematological malignancies exceeding 10.0% of all marrow cells, and they make a paraprotein that is a marker of the disease. Myeloma is one of the most common types of hematological malignancies in humans. Genetic bio-markers have been used for prognostic markers in patients diagnosed with MM. The genetic and genomic changes have been identified using karyotyping, fluorescent in situ hybridization (FISH), next generation sequencing (NGS), specifically whole-genome sequencing or exome sequencing. Circulatory plasma cells, circulating free DNA (cfD-NA) and microRNAs (miRNAs) comprised in liquid biopsy are potentially used in diagnosis/prognosis of MM. In this study, we analyzed and compared results of karyo-typing, FISH and NGS in 35 MM cases. Diagnostic strategies are expanding rapidly and newly developed NGS-based testing may help the understanding of the complexities of genetic alterations in karyotypically normal cases.

Multiple Myeloma: Available Therapies and Causes of Drug Resistance

Multiple myeloma (MM) is the second most common blood cancer. Treatments for MM include corticosteroids, alkylating agents, anthracyclines, proteasome inhibitors, immunomodulatory drugs, histone deacetylase inhibitors and monoclonal antibodies. Survival outcomes have improved substantially due to the introduction of many of these drugs allied with their rational use. Nonetheless, MM patients successively relapse after one or more treatment regimens or become refractory, mostly due to drug resistance. This review focuses on the main drugs used in MM treatment and on causes of drug resistance, including cytogenetic, genetic and epigenetic alterations, abnormal drug transport and metabolism, dysregulation of apoptosis, autophagy activation and other intracellular signaling pathways, the presence of cancer stem cells, and the tumor microenvironment. Furthermore, we highlight the areas that need to be further clarified in an attempt to identify novel therapeutic targets to counteract drug resistance in MM patients.

Cytogenetic Abnormalities in Multiple Myeloma Patients at a Tertiary Healthcare Center in India

Objective:

Multiple myeloma (MM) is a clinically and genetically heterogeneous plasma cell neoplasm. The prognosis of MM patients is dependent on several factors including the patient’s age, the stage of disease and genetic alterations. This study aimed to determine the frequency of common chromosomal abnormalities and their significance in MM patients referred to a tertiary healthcare center in India.

Methods:

Fluorescence in situ hybridization on interphase nuclei from bone marrow cells using seven MM-specific probes for recurrent aberrations was performed in a total of 215 newly diagnosed patients.

Results:

Chromosomal abnormalities were detected in 161 (74.9%) MM patients in this study. The most frequent aberration was trisomy(ies) involving only gain of chromosomes in 48 (22.3%) cases. A translocation involving the IGH gene alone or accompanied by trisomy(ies) or by monosomy 13/13q deletion or by both was registered in 80 (37.2%) patients. Atypical patterns such as a deletion of the IGH variable segment (IGHv) on the derivative chromosome 14 or on the native (normal) chromosome 14, biallelic deletion of IGHv, deletion of the IGH constant segment on the rearranged chromosome14 and extra fusions were noticed in 21 (9.8%) patients with an IGH rearrangement. Monosomy 13/deletion 13q was identified singly or as part of a complex karyotype in 74 patients (34.4%). Clonal heterogeneity and additional abnormalities including TP53 deletion and monosomies of chromosomes 4, 9, 14 and 16 were recorded in 18.6% and 16.3% of patients respectively. Patients with abnormalities exhibited plasmacytosis, reduced hemoglobin value and high level of ß2-microglobulin.

Conclusions:

A lower median age and a low frequency of IGH translocations particularly t(11;14) and chromosome 13 abnormalities suggest ethnic diversity. Further investigations on genetic alterations including IGH deletions will contribute to improved insights into the biology of myeloma disease, risk stratification and patient management.

Recent advances in cytogenetic characterization of multiple myeloma

The detection of cytogenetic abnormalities in multiple myeloma (MM) has received more importance over last years for risk stratification and the new risk-adapted treatment strategies. Conventional G-banding analysis should be included in a routine procedure for the initial diagnostic workup for patients suspected of MM. However, the detection of chromosomal abnormalities in MM by conventional cytogenetics is limited owing to the low proliferative activity of malignant plasma cells as well as the low number of plasma cells in bone marrow specimens. Fluorescence in situ hybridization (FISH) or microarray-based technologies can overcome some of those drawbacks and detect specific target arrangements as well as chromosomal copy number changes. In this review, we will discuss different cytogenetic approaches and compare their strength and weakness to provide genetic information for risk stratification and prediction of outcome in MM patients.

The Utilization of Karyotyping, iFISH, and MLPA for the Detection of Recurrence Genetic Aberrations in Multiple Myeloma

Multiple myeloma (MM) is a hematological malignancy characterized by abnormal accumulation of clonal plasma cells in the bone marrow. Recently, multiplex ligation-dependent probe amplification (MLPA) has emerged as an effective and robust method for detection of common genetic alterations in MM patients. Here, we aimed to confirm MLPA utility for this purpose and furthermore to test the feasibility of a combination of karyotyping, interphase fluorescence in situ hybridization (iFISH) and MLPA methods for diagnosis, prognostic assessment and risk stratification of MM. Thirty-five genomic DNA samples isolated from CD138-enriched plasma cells from bone marrow of MM patients were analyzed using the MLPA method. We found that amp (1q) was the most frequent genetic alteration (48.6%) in the tested samples, followed by del (1p) and del (13q) (34.3%). Moreover, concordant results between sensitivity and specificity of iFISH and MLPA for the detection of del (13q) (p-value >0.05) and del (17p) (p-value >0.05) were obtained. In summary, we could provide evidence of MLPA assay utility for the detection of common genetic alterations in MM. The combination of karyotyping, iFISH, and MLPA proved very helpful for clinical risk stratification.

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.

A retrospective analysis of cytogenetic alterations in patients with newly diagnosed multiple myeloma: a single center study in Korea

Background

The accurate identification of cytogenetic abnormalities in multiple myeloma (MM) has become more important over recent years for the development of new diagnostic and prognostic markers. In this study, we retrospectively analyzed the cytogenetic aberrations in MM cases as an initial assessment in a single institute.

Methods

We reviewed the cytogenetic results from 222 patients who were newly diagnosed with MM between January 2000 and December 2015. Chromosomal analysis was performed on cultured bone marrow samples by standard G-banding technique. At least 20 metaphase cells were analyzed for karyotyping.

Results

Clonal chromosome abnormalities were detected in 45.0% (100/222) of the patients. Among these results, 80 cases (80.0%) had both numerical and structural chromosome abnormalities. Overall hyperdiploidy with structural cytogenetic aberrations was the most common finding (44.0%), followed by hypodiploidy with structural aberrations (28.0%). Amplification of the long arm of chromosome 1 and -13/del(13q) were the most frequent recurrent abnormalities, and were detected in 50 patients (50.0%) and 40 patients (40.0%) with clonal abnormalities, respectively. The most common abnormality involving 14q32 was t(11;14)(q13;q32), which was observed in 19 cases.

Conclusion

These findings demonstrate that myeloma cells exhibit complex aberrations regardless of ploidy, even from a single center in Korea. Conventional cytogenetic analysis should be included in the initial diagnostic work-up for patients suspected of having MM.