Prognostic impact of hyperdiploidy in multiple myeloma patients with high-risk cytogenetics: a pilot study in China

A diagnostic approach to detect cytogenetic heterogeneity and its prognostic significance in multiple myeloma

Objective

Multiple myeloma (MM) is a hematological disorder involving the uncontrolled proliferation of clonal plasma cells and its accumulation in the bone marrow. This study analyzed the frequency, cytogenetic heterogeneity, and clinical characteristics of patients with MM.

Methods

Bone marrow aspirates were obtained from 72 patients with MM and evaluated by conventional cytogenetics (CCs) and interphase fluorescence in situ hybridization (iFISH) techniques for a panel of probes, including immunoglobulin heavy chain (IgH)/CCND1, IgH/fibroblast growth factor receptor 3 (FGFR3), IgH/MAFB, 13q deletion, and deletion 17p.

Results

CCs revealed abnormal karyotypes in 39% of the patients examined. The incidence of hypodiploidy was 28% (20/72) while that of hyperdiploidy was 10% (7/72). iFISH analysis revealed t(11;14) in 6% (4/72) and t(4;14) in 11% (8/72) of patients. Patients with hyperdiploidy and hypodiploidy were associated with several monosomies and trisomies. Kaplan-Meier analysis revealed a significant difference between positive and negative groups for t(4;14), trisomy 14, and monosomy 13; this was associated with a shorter survival time. Cox proportional analysis identified t(4;14) (P = 0.032), trisomy 14 (P = 0.004), and monosomy 13 (P = 0.009), as significant factors with hazard ratio of 0.187 [confidence interval (CI): 0.041-0.862], 0.109 [CI: 0.024-0.500] and 0.134 [CI: 0.030-0.600].

Conclusion

In addition to cytogenetic abnormalities, iFISH analysis revealed significant heterogeneity among patients with MM. Cytogenetic heterogeneity in patients with MM should be considered as a major prognostic marker contributing to the variability of the disease. Our findings suggest that these abnormalities are independent prognostic factors.

Current perspectives on interethnic variability in multiple myeloma: Single cell technology, population pharmacogenetics and molecular signal transduction

•

This review discusses the emerging single cell technologies and applications in Multiple myeloma (MM), population pharmacogenetics of MM, resistance to chemotherapy, genetic determinants of drug-induced toxicity, molecular signal transduction.

•

The role(s) of epigenetics and noncoding RNAs including microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) that influence the risk and severity of MM are also discussed.

•

It is understood that ethnic component acts as a driver of variable response to chemotherapy in different sub-populations globally.

•

This review augments our understanding of genetic variability in ‘myelomagenesis’ and drug-induced toxicity, myeloma microenvironment at the molecular and cellular level, and developing precision medicine strategies to combat this malignancy.

•

The emerging single cell technologies hold great promise for enhancing our understanding of MM tumor heterogeneity and clonal diversity.

Multiple myeloma (MM) is an aggressive cancer characterised by malignancy of the plasma cells and a rising global incidence. The gold standard for optimum response is aggressive chemotherapy followed by autologous stem cell transplantation (ASCT). However, majority of the patients are above 60 years and this presents the clinician with complications such as ineligibility for ASCT, frailty, drug-induced toxicity and differential/partial response to treatment. The latter is partly driven by heterogenous genotypes of the disease in different subpopulations. In this review, we discuss emerging single cell technologies and applications in MM, population pharmacogenetics of MM, resistance to chemotherapy, genetic determinants of drug-induced toxicity, molecular signal transduction, as well as the role(s) played by epigenetics and noncoding RNAs including microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) that influence the risk and severity of the disease. Taken together, our discussions further our understanding of genetic variability in ‘myelomagenesis’ and drug-induced toxicity, augment our understanding of the myeloma microenvironment at the molecular and cellular level and provide a basis for developing precision medicine strategies to combat this malignancy.

Evidence for ABL Amplification in Multiple Myeloma and Therapeutic Implications

Background

Cytogenetic abnormalities are considered initiating events in the pathogenesis of multiple myeloma (MM) and are assumed to be of clinical significance.

Methods

Fluorescence in situ hybridization (FISH) was used to analyze chromosomal architecture in 101 patients with MM. We evaluated overall patient survival and assessed the cytotoxicity of imatinib against MM cells using a CCK8 assay.

Results

ABL gene amplification was detected in 67 patients (66.3%). However, ABL gene amplification was not associated with clinical features, cytogenetic abnormalities (c-Myc amplification, IGH rearrangement, RB1 deletion, p53 deletion, or 1q21 amplification), or overall survival. ABL amplification in MM cell lines (LP-1 and U266) was revealed by FISH. Furthermore, the ABL protein was easily detectable in MM cell lines and some tumor cells by western blotting. A CCK8 assay indicated limited cytotoxicity of imatinib against MM cells.

Conclusions

Our study firstly discussed ABL gene amplification was prevalent in MM cells, and we believe that the ABL gene would potentially be a useful target in the treatment of combination strategy for MM with ABL amplification in the future.

Partial immunoparesis contributes to risk of early infections in patients with multiple myeloma

Background

Partial immunoparesis, which means at least two suppressed uninvolved immunoglobulins (Igs), had been reported to be associated with poor prognosis in patients with multiple myeloma (MM), but the impact on early infections remains unknown. The purpose of our study was to determine the prognostic implications of partial immunoparesis on early grade ≥3 infections in patients with MM.

Methods

Herein we retrospectively analyzed the clinical data of 123 MM patients between 2012 and 2020 at Nanfang Hospital. All patients received bortezomib-based regimens. The relationship between early grade ≥3 infections and partial immunoparesis was investigated using Cox regression analysis.

Results

Our data showed partial immunoapresis was found in 63% MM patients. Partial immunoparesis was significantly related to elevated beta-2-microglobulin (B2M), decreased estimated glomerular filtration rate (eGFR) and progressive international staging system (ISS) stage (P<0.05). Especially, univariate Cox regression analysis showed partial immunoparesis was significantly correlated with early grade ≥3 infections (P=0.003). Moreover, multivariate Cox regression analysis showed partial immunoparesis was an independent significant prognostic factor for early grade ≥3 infections [odds ratio (OR) =3.048; 95% confidence interval (CI): 1.429–6.504; P=0.004]. Furthermore, partial immunoapresis could improve the infection risk model built by Dumontet et al.

Conclusions

Our study showed that partial immunoparesis could predict early infections in patients with MM, which may be used to identify the high risk patients for infections and guide strategies for infection prevention.

Genetic pathogenesis of immunoglobulin light chain amyloidosis: basic characteristics and clinical applications

Immunoglobulin light chain amyloidosis (AL) is an indolent plasma cell disorder characterized by free immunoglobulin light chain (FLC) misfolding and amyloid fibril deposition. The cytogenetic pattern of AL shows profound similarity with that of other plasma cell disorders but harbors distinct features. AL can be classified into two primary subtypes: non-hyperdiploidy and hyperdiploidy. Non-hyperdiploidy usually involves immunoglobulin heavy chain translocations, and t(11;14) is the hallmark of this disease. T(11;14) is associated with low plasma cell count but high FLC level and displays distinct response outcomes to different treatment modalities. Hyperdiploidy is associated with plasmacytosis and subclone formation, and it generally confers a neutral or inferior prognostic outcome. Other chromosome abnormalities and driver gene mutations are considered as secondary cytogenetic aberrations that occur during disease evolution. These genetic aberrations contribute to the proliferation of plasma cells, which secrete excess FLC for amyloid deposition. Other genetic factors, such as specific usage of immunoglobulin light chain germline genes and light chain somatic mutations, also play an essential role in amyloid fibril deposition in AL. This paper will propose a framework of AL classification based on genetic aberrations and discuss the amyloid formation of AL from a genetic aspect.

Genetic Abnormalities in Multiple Myeloma: Prognostic and Therapeutic Implications

Some genetic abnormalities of multiple myeloma (MM) detected more than two decades ago remain major prognostic factors. In recent years, the introduction of cutting-edge genomic methodologies has enabled the extensive deciphering of genomic events in MM. Although none of the alterations newly discovered have significantly improved the stratification of the outcome of patients with MM, some of them, point mutations in particular, are promising targets for the development of personalized medicine. This review summarizes the main genetic abnormalities described in MM together with their prognostic impact, and the therapeutic approaches potentially aimed at abrogating the undesirable pathogenic effect of each alteration.

Genome instability in multiple myeloma

Multiple myeloma (MM) is an incurable plasma cell malignancy characterized by clonal proliferation of plasma cells and a heterogenous genomic landscape. Copy number and structural changes due to chromosomal instability (CIN) are common features of MM. In this review, we describe how primary and secondary genetic events caused by CIN can contribute to increased instability across the genome of malignant plasma cells; with a focus on specific driver genomic events, and how they interfere with cell-cycle checkpoints, to prompt accelerated proliferation. We also provide insight into other forms of CIN, such as chromothripsis and chromoplexy. We evaluate how the tumor microenvironment can contribute to a further increase in chromosomal instability in myeloma cells. Lastly, we highlight the role of certain mutational signatures in leading to high mutation rate and genome instability in certain MM patients. We suggest that assessing CIN in MM and its precursors states may help improve predicting the risk of progression to symptomatic disease and relapse and identifying future therapeutic targets.

IgH translocation with undefined partners is associated with superior outcome in multiple myeloma patients

BACKGROUND

In multiple myeloma (MM), impact of specific chromosomal translocations involving IgH (14q21 locus, including t(4;14), t(11;14), and t(14;16)) has been explored extensively. However, over 15% MM patients harboring IgH translocation with undefined partners have long been ignored.

METHODS

A prospective non-randomized cohort study with a total of 715 newly-diagnosed MM cases was conducted, 13.6% of whom were t(14;undefined) positive. The whole cohort was divided into four groups: no IgH split (47.7%); t(14;undefined) (13.6%); t(11;14) (17.6%); and t(4;14) or t(14;16) group (21.1%).

RESULTS

Median OS for the four groups was 84.2, not reached (NR), 58.7, and 44.2 months, respectively, with P values for t(14;undefined) vs no IgH split, t(11;14), and t(4;14)/t(14;16) groups of 0.197, 0.022, and 0.001, respectively. In bortezomib-based group, the survival advantage gained by t(14;undefined) group was much more significant compared to t(11;14) and t(4;14)/t(14;16) groups. Importantly, t(14;undefined) turned out to be an independent predictive factor for longer OS of MM patients in multivariate analysis, especially in the context of bortezomib treatment. Similar results were also observed in the PUMCH external validation cohort.

CONCLUSION

Collectively, our data confirmed and externally validated the favorable prognosis of the t(14;undefined) groups, especially in the era of novel agents.

Achieving minimal residual disease-negative by multiparameter flow cytometry may ameliorate a poor prognosis in MM patients with high-risk cytogenetics: a retrospective single-center analysis

The aim of our study was to evaluate the prognostic impact of minimal residual disease (MRD) and high-risk cytogenetics (HRCs) on outcomes in multiple myeloma (MM) patients. We applied multiparameter flow cytometry (MFC) to detect MRD in 123 consecutive patients diagnosed with MM for the first time who achieved very good partial remission (VGPR) or better after bortezomib or thalidomide-based induction therapy. Moreover, we examined the cytogenetic features of MM patients using magnetic-activated cell sorting and interphase fluorescence in situ hybridization (MACS-iFISH) at diagnosis. In all 123 MM patients, progression-free survival (PFS) and overall survival (OS) were better in the MRD- group (n = 31) than in the MRD+ group (n = 92) (median PFS: not reached (NR) vs. 26 months (m), P = 0.0002; 4-year OS, 91.7% vs. 66.3%, P = 0.008). PFS and OS were significantly shorter for each increase of one log per MRD level (P < 0.0001 and P = 0.001). The median PFS of the four groups according to the ratio of aberrant plasma cells (less than 0.01%, 0.01-0.1%, 0.1-1%, and more than 1%) were NR, 37 m, 26 m, and 15 m, respectively, and the 4-year OS rates were 91.7%, 69.3%, 76.1%, and 54.0%, respectively. In addition, our results show that PFS and OS were better for the standard-risk cytogenetic (SRC) patients than the HRC patients (median PFS: NR vs. 26 m, P = 0.004; 3-year OS: 95.8% vs. 76.0%, P = 0.006). The independent predictors of PFS were HRC and MRD+, which had hazard ratios of 1.901 (95% CI 1.094-3.303) and 3.486 (95% CI 1.449-8.386), respectively; while those for OS were an LDH level ≥ 250 U/L, HRC, and MRD+, which had hazard ratios of 2.789 (95% CI 1.080-7.199), 2.697 (95% CI 1.053-6.907), and 7.714 (95% CI 1.040-57.227), respectively. Furthermore, for SRC patients or HRC patients, PFS and OS were all longer in MRD- than in MRD+ patients. Strikingly, there was no significant difference in PFS or OS between the MRD-HRC and MRD+SRC groups (median PFS 45 vs. 34 m, P = 0.300; 4-year OS 100% vs. 83.6%, P = 0.196). PFS was superior in MRD-SRC than in MRD-HRC (NR vs. 45 m, P = 0.035); however, there was no significant difference in the 4-year OS between MRD-SRC and MRD-HRC (87.5% vs 100%, P = 0.480). MRD+ and HRCs were both independent prognostic factors in MM patients. Moreover, achieving MRD- may ameliorate a poor prognosis in MM patients with HRCs.