Expression of CD56/neural cell adhesion molecule correlates with the presence of lytic bone lesions in multiple myeloma and distinguishes myeloma from monoclonal gammopathy of undetermined significance and lymphomas with plasmacytoid differentiation

Progression of monoclonal gammopathy of undetermined significance to multiple myeloma is associated with enhanced translational quality control and overall loss of surface antigens

BACKGROUND

Despite significant advancements in treatment strategies, multiple myeloma remains incurable. Additionally, there is a distinct lack of reliable biomarkers that can guide initial treatment decisions and help determine suitable replacement or adjuvant therapies when relapse ensues due to acquired drug resistance.

METHODS

To define specific proteins and pathways involved in the progression of monoclonal gammopathy of undetermined significance (MGUS) to multiple myeloma (MM), we have applied super-SILAC quantitative proteomic analysis to CD138 + plasma cells from 9 individuals with MGUS and 37 with MM.

RESULTS

Unsupervised hierarchical clustering defined three groups: MGUS, MM, and MM with an MGUS-like proteome profile (ML) that may represent a group that has recently transformed to MM. Statistical analysis identified 866 differentially expressed proteins between MM and MGUS, and 189 between MM and ML, 177 of which were common between MGUS and ML. Progression from MGUS to MM is accompanied by upregulated EIF2 signaling, DNA repair, and proteins involved in translational quality control, whereas integrin- and actin cytoskeletal signaling and cell surface markers are downregulated.

CONCLUSION

Compared to the premalignant plasma cells in MGUS, malignant MM cells apparently have mobilized several pathways that collectively contribute to ensure translational fidelity and to avoid proteotoxic stress, especially in the ER. The overall reduced expression of immunoglobulins and surface antigens contribute to this and may additionally mediate evasion from recognition by the immune apparatus. Our analyses identified a range of novel biomarkers with potential prognostic and therapeutic value, which will undergo further evaluation to determine their clinical significance.

A Spectrum of Metastases to the Breast: Radiologic-Pathologic Correlation

Metastases to the breast from non-mammary origin are rare. The majority of these lesions appear as secondary manifestations of melanoma and lymphoma, followed by lung carcinomas, gynecological carcinomas, and sarcomas. There has been a steady trend of an increase in diagnosis of intramammary metastases owing to the current advances in imaging technology. Imaging features depend on the type of primary neoplasm and route of dissemination, some of which resemble primary breast cancer and benign breast entities. There are certain imaging features that raise the level of suspicion for metastases in the correct clinical context. However, imaging manifestations of intramammary metastases do not always comply with the known classic patterns. The aim of this review is to clarify these features, emphasizing radiologic-pathologic correlation and a multidisciplinary approach, since most cases are found in patients with advanced disease.

Newly diagnosed multiple myeloma patients with CD56 expression benefit more from autologous stem cell transplantation

BACKGROUND

Several studies showed that lack of CD56 expression was a poor prognostic factor for patients with newly diagnosed multiple myeloma (NDMM). However, other studies were not able to confirm the prognostic value of CD56 in NDMM. This study aimed to evaluate the prognostic value of CD56 expression for patients with NDMM who received autologous stem cell transplantation (ASCT).

METHODS

We retrospectively analyzed 370 patients with NDMM under 66 years old and the propensity score matching technique was used to reduce the bias between two groups.

RESULTS

CD56 expression was observed in 250 (67.6%) patients, and only half of transplant-eligible patients received ASCT for financial and adverse effects concerns after induction therapy. 54.8% (137/250) CD56 positive patients received ASCT; and 47.5% (57/120) CD56 negative patients received ASCT. Univariate and multivariate analyses showed that ASCT was correlated with longer overall survival (OS) (p < 0.001) and progression-free survival (PFS) (p < 0.001) for CD56 positive patients. However, ASCT had no impact on OS and PFS in univariate and multivariate analysis (p > 0.05). In the propensity score matching analysis, 186 CD56 positive patients were identified, 93 patients had received ASCT and 93 patients had no ASCT. Among 120 CD56 negative patients, 80 patients, 40 in each group, were identified. Among 186 matched CD56 positive patients, patients with ASCT had longer OS (87.6 vs.56.1 months, p = 0.049) and PFS (36.7 vs.30.9 months, p = 0.040). However, ASCT had no impact on OS and PFS for matched CD56 negative patients (p > 0.05).

CONCLUSIONS

These results demonstrated that ASCT may improve OS and PFS of CD56 positive patients and had no impact on survival of CD56 negative patients.

The Route of the Malignant Plasma Cell in Its Survival Niche: Exploring “Multiple Myelomas”

Growing evidence points to multiple myeloma (MM) and its stromal microenvironment using several mechanisms to subvert effective immune and anti-tumor responses. Recent advances have uncovered the tumor-stromal cell influence in regulating the immune-microenvironment and have envisioned targeting these suppressive pathways to improve therapeutic outcomes. Nevertheless, some subgroups of patients include those with particularly unfavorable prognoses. Biological stratification can be used to categorize patient-, disease- or therapy-related factors, or alternatively, these biological determinants can be included in a dynamic model that customizes a given treatment to a specific patient. Genetic heterogeneity and current knowledge enforce a systematic and comprehensive bench-to-bedside approach. Given the increasing role of cancer stem cells (CSCs) in better characterizing the pathogenesis of solid and hematological malignancies, disease relapse, and drug resistance, identifying and describing CSCs is of paramount importance in the management of MM. Even though the function of CSCs is well-known in other cancer types, their role in MM remains elusive. With this review, we aim to provide an update on MM homing and resilience in the bone marrow micro milieu. These data are particularly interesting for clinicians facing unmet medical needs while designing novel treatment approaches for MM.

Redefining CD56 as a biomarker and therapeutic target in Multiple Myeloma

Multiple myeloma (MM) cells aberrantly express surface antigens compared to normal plasma cells. Among others, CD56 is present at variable levels in approximately 70% of MM patients; however very little is known about CD56 role in MM. We demonstrated that MM patients with more than 10 percent of CD56-expressing clonal MM cells have inferior clinical outcomes. By gain-of and loss-of function models, we revealed that CD56 promotes MM cell growth, survival, and adhesion to stromal cells. These protumoral effects are induced by the activation of the RSK2/CREB1 signaling pathway, with increased mRNA and protein levels of the anti-apoptotic genes BCL2 and MCL1. Consequently, the genomic and pharmacological inhibition of RSK2 or CREB1 specifically induced MM cell death in CD56-expressing MM cells. Finally, we observed that CD56 signaling decreases CRBN expression, reducing responses to lenalidomide. RSK2 or CREB1 inhibition increased CRBN levels and were synergic with lenalidomide in inducing cell death, especially in CD56-expressing MM cells. In conclusion, our findings demonstrate that CD56 promotes MM cell growth, and pave the way to novel therapies based on targeting CD56, along with the use of CD56 as a predictive biomarker for MM therapies. Implications: Multiple myeloma (MM) is an incurable, genetically heterogeneous disease, without available tailored therapeutic approaches. CD56 signaling promotes MM growth and adhesion, by activating CREB1 target genes, MCL1 and BCL2. Inhibition of CREB1 alone or in combination with lenalidomide is an unexplored synthetic lethal approach in CD56-expressing MM patients.

Emerging Role of Antibody-Drug Conjugates and Bispecific Antibodies for the Treatment of Multiple Myeloma

Multiple myeloma (MM) is characterized by malignant proliferation of malignant plasma cells; it is the second most common hematological malignancy associated with significant morbidity. Genetic intricacy, instability, and diverse clinical presentations remain a barrier to cure. The treatment of MM is modernized with the introduction of newer therapeutics agents, i.e., target-specific monoclonal antibodies. The currently available literature lacks the benefits of newer targeted therapy being developed with an aim to reduce side effects and increase effectiveness, compared to conventional chemotherapy regimens. This article aims to review literature about the current available monoclonal antibodies, antibody-drug conjugates, and bispecific antibodies for the treatment of MM.

Plasma cell myeloma: role of histopathology, immunophenotyping, and genetic testing

Myeloma is a malignant neoplasm of plasma cells with complex pathogenesis. Diagnosis and risk stratification require the integration of histology, radiology, serology, and genetic data. Bone marrow biopsies are essential for myeloma diagnosis by providing material for histologic and cytologic assessment as well as immunophenotypic and genetic studies. Flow cytometry and genetic studies are, in particular, becoming increasingly important for diagnosis, risk stratification, and assessment of treatment response. Myeloma has traditionally been characterized by recurrent cytogenetic abnormalities that can be divided into two subtypes: hyperdiploid, characterized by trisomies, and non-hyperdiploid, characterized by translocations involving chromosome 14. These abnormalities are thought to be primary events, initiating a premalignant state, which progresses to myeloma through the acquisition of secondary mutations. The emergence of next-generation sequencing has led to the discovery of numerous mutations and gene fusions that comprise the heterogenous genomic landscape of myeloma. As the underlying pathogenesis of myeloma continues to be delineated, possible therapeutic targets have also emerged. Herein, we describe the importance of histology, immunophenotype, and mutational analysis in the assessment of myeloma.

Current Understanding of Myelomatous Mesenchymal Stromal Cells Extended through Advances in Experimental Methods

Simple Summary

As the amount of information available has grown, now it is known that many types of non-hematopoietic cells, including mesenchymal stem/progenitor cells, mature mesenchymal cells, and endothelial cells, as well as mature hematopoietic cells such as monocytes, macrophages, T-cells, and B-cells, have roles in the pathogenesis of multiple myeloma. This review focuses on the role of mesenchymal cells in the microenvironment of multiple myeloma. We summarize the experimental strategies and current understanding of the biological roles in the pathogenesis of myeloma. Furthermore, we discuss the possible clinical applications targeting mesenchymal cells.

Abstract

Multiple myeloma is an incurable cancer formed by malignant plasma cells. For the proliferation and survival of myeloma cells, as well as the occurrence of the complications, numerous intra- and extra-cellular mechanisms are involved. The interaction of myeloma cells with the microenvironment is known to be one of the most critical mechanisms. A specific microenvironment could affect the progression and growth of tumor cells, as well as drug resistance. Among various microenvironment components, such as hematological and non-hematological cells, and soluble factors (cytokines, chemokines, and extracellular matrix (ECM) proteins), in this review, we focus on the role of mesenchymal cells. We aimed to summarize the experimental strategies used for conducting studies and current understanding of the biological roles in the pathogenesis of myeloma. Furthermore, we discuss the possible clinical applications targeting mesenchymal cells.

Is absence of CD56 a predictive factor for peripheral blood stem cell mobilization failure in patients with multiple myeloma?

BACKGROUND

CD56 is believed to play a major role in MM pathogenesis with a 70% to 80% expression rate in malignant plasma cells at the time of diagnosis. Our objective in this study was to investigate the relationship between the characteristics of CD56 expression in bone marrow aspiration material at the time of diagnosis and the success of stem cell mobilization in patients diagnosed with MM.

METHODS

This monocenter study included 94 patients who were diagnosed with MM and had a stem cell mobilization procedure for autologous hematopoietic stem cell transplantation. The primary endpoint of the study was to compare the mobilization success between the groups with and without CD56 expression. The secondary endpoint was to identify other factors affecting mobilization failure outside CD56.

RESULTS

At the time of diagnosis, 49 (52.1%) patients had CD56 expression and 45 (47.9%) did not. Mobilization failed in 11 (11.7%) patients. Age, gender, ISS stage and the number of premobilization treatment regimens were not found predictive of mobilization failure. CD56 negativity was 42.2% in the group that had mobilization success and 90.9% in the group that had mobilization failure (P = .001).

CONCLUSIONS

The fact that CD56 residing on the membrane enables interaction between bone marrow cells and ECM and functions as a signal molecule increases sensitivity to the chemotherapy and G-CSF that are used for mobilization. We found that absence of CD56 can be used as a predictive factor for mobilization failure at the time of diagnosis.

The clinical and pathological features of plasma cell myeloma post solid organ transplantation

Plasma cell neoplasms (PCNs), comprising plasma cell myelomas (PCMs) and plasmacytomas, which occur after solid organ transplantation, represent rare subtypes of monomorphic post-transplant lymphoproliferative disorders (M-PTLDs). Data regarding the clinical and pathological features of post-transplant (PT)-PCMs are limited. To gain a better understanding of disease biology, we performed comprehensive immunophenotypic analysis, reviewed cytogenetic analysis results and evaluated clinical outcomes of PT-PCMs diagnosed and treated at our institution. Fifteen PT-PCM (M: F - 4:1) and two PT-MGUS (two males) cases were identified. The median age of PT-PCM patients was 68 years (29-79 years) and PCMs presented at a median of 9.7 years (0.5-24.7 years) after transplantation. The PT-PCMs accounted for 11.6% of all M-PTLDs and the period prevalence was 9/3108 (0.29%), 3/1071 (0.28%), 2/1345 (0.15%) and 1/878 (0.11%) post kidney, heart, liver and lung transplantation. Lytic bone disease was observed in 1/11 (9%) patients. Marrow plasma cell infiltration ranged from 10%-70% (median 20%), with 10/15 (67%) and 5/15 (33%) cases manifesting immature and plasmablastic morphology. The immunophenotype of all cases and cytogenetic abnormalities, identified in 60% of cases, were similar to multiple myeloma (MM) of immunocompetent individuals. All PT-PCMs were EBER negative. Ten of 11 (91%) patients with active MM were treated, all with proteasome inhibitor-based therapy. Treatment response and 5-year overall survival (54.5%) was comparable to MM of immunocompetent individuals. However, the survival of patients with plasmablastic PCMs was inferior to those with immature PCMs. 0ur findings indicate PT-PCMs to be predominantly late onset PTLDs that have similar clinicopathologic characteristics as conventional MM.

[Bone disease as the first manifestation of systemic AL-amyloidosis]

Our case demonstrates severe bone disease in primary AL-amyloidosis without concomitant multiple myeloma. A 30-year-old man had spontaneous vertebral fracture Th8. A computed tomography scan suggested multiple foci of lesions in all the bones. In bone marrow and resected rib werent detected any tumor cells. After 15 years from the beginning of the disease, nephrotic syndrome developed. Based on the kidney biopsy, AL-amyloidosis was confirmed. Amyloid was also detected in the bowel and bone marrow. On the indirect signs (thickening of the interventricular septum 16 mm and increased NT-proBNP 2200 pg/ml), a cardial involvement was confirmed. In the bone marrow (from three sites) was found 2.85% clonal plasma cells with immunophenotype СD138+, СD38dim, СD19-, СD117+, СD81-, СD27-, СD56-. FISH method revealed polysomy 5,9,15 in 3% of the nuclei. Serum free light chain Kappa 575 mg/l (/44.9) was detected. Multiple foci of destruction with increased metabolic activity (SUVmax 3.6) were visualized on PET-CT, and an surgical intervention biopsy was performed from two foci. The number of plasma cells from the destruction foci was 2.5%, and massive amyloid deposition was detected. On CT scan foci of lesions differed from bone lesions at multiple myeloma. Bone fragments of point and linear type (button sequestration) were visualized in most of the destruction foci. The content of the lesion was low density. There was no extraossal spread from large zones of destruction. There was also spontaneous scarring of the some lesions (without therapy). Thus, the diagnosis of multiple myeloma was excluded on the basis based on x-ray signs, of the duration of osteodestructive syndrome (15 years), the absence of plasma infiltration in the bone marrow, including from foci of bone destruction by open biopsy. This observation proves the possibility of damage to the skeleton due to amyloid deposition and justifies the need to include AL-amyloidosis in the spectrum of differential diagnosis of diseases that occur with osteodestructive syndrome.

RET-independent signaling by GDNF ligands and GFRα receptors

The discovery in the late 1990s of the partnership between the RET receptor tyrosine kinase and the GFRα family of GPI-anchored co-receptors as mediators of the effects of GDNF family ligands galvanized the field of neurotrophic factors, firmly establishing a new molecular framework besides the ubiquitous neurotrophins. Soon after, however, it was realized that many neurons and brain areas expressed GFRα receptors without expressing RET. These observations led to the formulation of two new concepts in GDNF family signaling, namely, the non-cell-autonomous functions of GFRα molecules, so-called trans signaling, as well as cell-autonomous functions mediated by signaling receptors distinct from RET, which became known as RET-independent signaling. To date, the best studied RET-independent signaling pathway for GDNF family ligands involves the neural cell adhesion molecule NCAM and its association with GFRα co-receptors. Among the many functions attributed to this signaling system are neuronal migration, neurite outgrowth, dendrite branching, spine formation, and synaptogenesis. This review summarizes our current understanding of this and other mechanisms of RET-independent signaling by GDNF family ligands and GFRα receptors, as well as their physiological importance.

Targeted Therapy With Immunoconjugates for Multiple Myeloma

The introduction of proteasome inhibitors (PI) and immunomodulatory drugs (IMiD) has markedly increased the survival of multiple myeloma (MM) patients. Also, the unconjugated monoclonal antibodies (mAb) daratumumab (anti-CD38) and elotuzumab (anti-SLAMF7) have revolutionized MM treatment given their clinical efficacy and safety, illustrating the potential of targeted immunotherapy as a powerful treatment strategy for MM. Nonetheless, most patients eventually develop PI-, IMiD-, and mAb-refractory disease because of the selection of resistant MM clones, which associates with a poor prognosis. Accordingly, these patients remain in urgent need of new therapies with novel mechanisms of action. In this respect, mAbs or mAb fragments can also be utilized as carriers of potent effector moieties to specifically target surface antigens on cells of interest. Such immunoconjugates have the potential to exert anti-MM activity in heavily pretreated patients due to their distinct and pleiotropic mechanisms of action. In addition, the fusion of highly cytotoxic compounds to mAbs decreases the off-target toxicity, thereby improving the therapeutic window. According to the effector moiety, immunoconjugates are classified into antibody-drug conjugates, immunotoxins, immunocytokines, or radioimmunoconjugates. This review will focus on the mechanisms of action, safety and efficacy of several promising immunoconjugates that are under investigation in preclinical and/or clinical MM studies. We will also include a discussion on combination therapy with immunoconjugates, resistance mechanisms, and future developments.

Bone Pathology for Hematopathologists

Bone pathology can be challenging because the skeleton is a living tissue prone to developing a diverse array of inflammatory, metabolic, genetic, reactive, circulatory, and neoplastic abnormalities. Several areas of bone pathology are particularly difficult or problematic for hematopathologists given the close resemblance of some hematologic entities to primary/metastatic bone lesions; examples include plasmacytic disorders versus osteoblastic tumors and lymphoma/leukemia versus round cell tumors of bone. This article provides a conceptual and practical overview of selective bone disorders commonly encountered in the differential diagnosis of hematologic diseases.

Role of CD138, CD56, and light chain immunohistochemistry in suspected and diagnosed plasma cell myeloma: A prospective study

Introduction:

Plasma cells (PCs) have conventionally been counted on the bone marrow aspirate, and small focal involvement may be missed even on bone marrow biopsy sections.

Material and Methods:

We aimed to study the role of CD138, CD56, anti-κ, and anti-λ immunohistochemistry (IHC) to separate PC myeloma from reactive plasmacytosis and to study the utility of these in cases suspected as myelomas and lacking >10% PCs on bone marrow aspirate. The study comprised 35 diagnosed myelomas, 20 reactive plasmacytosis, and 19 M-band positive suspected myelomas. CD138 IHC was performed on all cases along with CD56, anti-κ, and anti-λ IHC. PCs were counted on CD138-immunostained sections by manual count and by image analysis. In addition, CD56 expression was correlated with clinical features in diagnosed myeloma group.

Results:

In all cases, both manual counts and image analysis, PC counts were significantly higher on the CD138 stained sections than bone marrow aspirates. It was seen that the manual PC counts and image analysis counts were equivalent in diagnosed myeloma cases. CD56 expression was seen in ~62.85% diagnosed myeloma cases while it was negative in cases of reactive plasmacytosis. CD56 expression was significantly higher in patients with lytic lesions (78.26% vs. 21.74%). CD138, anti-κ, and anti-λ IHC also helped classify 11/19 (57.8%) cases correctly.

Conclusion:

The use of CD138 along with the light chain and CD56 IHC adds a high diagnostic value in myeloma patients and suspected myeloma cases. The PCs can be counted manually on the CD138-immunostained sections and correlate well with the counts obtained by image analysis.

Mesenchymal stem cells in multiple myeloma: a therapeutical tool or target?

Multiple myeloma (MM) is a malignant plasma cell (PC) disorder, characterized by a complex interactive network of tumour cells and the bone marrow (BM) stromal microenvironment, contributing to MM cell survival, proliferation and chemoresistance. Mesenchymal stem cells (MSCs) represent the predominant stem cell population of the bone marrow stroma, capable of differentiating into multiple cell lineages, including fibroblasts, adipocytes, chondrocytes and osteoblasts. MSCs can migrate towards primary tumours and metastatic sites, implying that these cells might modulate tumour growth and metastasis. However, this issue remains controversial and is not well understood. Interestingly, several recent studies have shown functional abnormalities of MM patient-derived MSCs indicating that MSCs are not just by-standers in the BM microenvironment but rather active players in the pathophysiology of this disease. It appears that the complex interaction of MSCs and MM cells is critical for MM development and disease outcome. This review will focus on the current understanding of the biological role of MSCs in MM as well as the potential utility of MSC-based therapies in this malignancy.

Diagnosis of Plasma Cell Dyscrasias and Monitoring of Minimal Residual Disease by Multiparametric Flow Cytometry

Plasma cell dyscrasia (PCD) is a heterogeneous disease that has seen a tremendous change in outcomes due to improved therapies. Over the past few decades, multiparametric flow cytometry has played an important role in the detection and monitoring of PCDs. Flow cytometry is a high-sensitivity assay for early detection of minimal residual disease (MRD) that correlates well with progression-free survival and overall survival. Before flow cytometry can be effectively implemented in the clinical setting, sample preparation, panel configuration, analysis, and gating strategies must be optimized to ensure accurate results. Current consensus methods and reporting guidelines for MRD testing are discussed.

Minimal Residual Disease Detection by Flow Cytometry in Multiple Myeloma: Why and How?

The outlook for myeloma patients has steadily improved with the introduction of newer drug combinations in recent years. Unlike older therapies that largely achieved only modest levels of neoplastic clone reduction, the newer drug combinations have led to deeper suppression of myeloma clones in most patients. Frequently the neoplastic clones become undetectable with traditional disease evaluation approaches. Recent studies using ultrasensitive disease monitoring have demonstrated that patients with disease undetectable by traditional techniques show wide heterogeneity in disease levels varying by several orders of magnitude. Moreover, measurement of the depth of disease suppression even at very low level has emerged as the most powerful prognostication tool in myeloma. Minimal (or measurable) residual disease (MRD) evaluation has also been proposed as a relevant tool in assessment of drug efficacy and in selection of further therapeutic options. In the face of the robust MRD measurement utility data, it has become critical to develop widely applicable disease monitoring techniques that can be applied to more patients in a variety of clinical setting. Both DNA-based and flow cytometry-based approaches have been successfully developed for this purpose achieving sensitivity approaching 1 neoplastic cell in a million. This review article focuses on the theoretical and practical aspects and challenges of deep MRD monitoring in myeloma by flow cytometry. Challenges of flow cytometric disease monitoring in the era of antigen-directed therapy are also discussed.

Lab-on-a-chip platforms for quantification of multicellular interactions in bone remodeling

Researchers have been using lab-on-a-chip systems to isolate factors for study, simulate laboratory analysis and model cellular, tissue and organ level processes. The technology is increasing rapidly, but the bone field has been slow to keep pace. Novel models are needed that have the power and flexibility to investigate the elegant and synchronous multicellular interactions that occur in normal bone turnover and in disease states in which remodeling is implicated. By removing temporal and spatial limitations and enabling quantification of functional outcomes, the platforms should provide unique environments that are more biomimetic than single cell type systems while minimizing complex systemic effects of in vivo models. This manuscript details the development and characterization of lab-on-a-chip platforms for stimulating osteocytes and quantifying bone remodeling. Our platforms provide the foundation for a model that can be used to investigate remodeling interactions as a whole or as a standard mechanotransduction tool by which isolated activity can be quantified as a function of load.

Genome-wide association study meta-analysis for quantitative ultrasound parameters of bone identifies five novel loci for broadband ultrasound attenuation

Osteoporosis is a common and debilitating bone disease that is characterised by low bone mineral density, typically assessed using dual-energy X-ray absorptiometry. Quantitative ultrasound (QUS), commonly utilising the two parameters velocity of sound (VOS) and broadband ultrasound attenuation (BUA), is an alternative technology used to assess bone properties at peripheral skeletal sites. The genetic influence on the bone qualities assessed by QUS remains an under-studied area. We performed a comprehensive genome-wide association study (GWAS) including low-frequency variants (minor allele frequency ≥0.005) for BUA and VOS using a discovery population of individuals with whole-genome sequence (WGS) data from the UK10K project (n = 1268). These results were then meta-analysed with those from two deeply imputed GWAS replication cohorts (n = 1610 and 13 749). In the gender-combined analysis, we identified eight loci associated with BUA and five with VOS at the genome-wide significance level, including three novel loci for BUA at 8p23.1 (PPP1R3B), 11q23.1 (LOC387810) and 22q11.21 (SEPT5) (P = 2.4 × 10-8 to 1.6 × 10-9). Gene-based association testing in the gender-combined dataset revealed eight loci associated with BUA and seven with VOS after correction for multiple testing, with one novel locus for BUA at FAM167A (8p23.1) (P = 1.4 × 10-6). An additional novel locus for BUA was seen in the male-specific analysis at DEFB103B (8p23.1) (P = 1.8 × 10-6). Fracture analysis revealed significant associations between variation at the WNT16 and RSPO3 loci and fracture risk (P = 0.004 and 4.0 × 10-4, respectively). In conclusion, by performing a large GWAS meta-analysis for QUS parameters of bone using a combination of WGS and deeply imputed genotype data, we have identified five novel genetic loci associated with BUA.

Flow cytometry-based immunophenotypic analysis of primary systemic light chain amyloidosis

Using flow cytometry, the present study aimed to investigate the immunophenotypic characteristics of malignant plasma cells (PCs) in the bone marrow of patients with primary systemic light chain amyloidosis (AL) compared with the characteristics of patients with multiple myeloma (MM). Flow cytometric results of 51 patients with AL and 150 patients with MM were reviewed. The proportion of total bone marrow PCs in the patients with AL was significantly lower than that in the patients with MM, 1.35% (0.3–9.5%) vs. 9.7% (0.4–75.7%); (P<0.001). The cells in 24/51 patients with AL comprised two distinct populations: Normal PCs and malignant PCs, whereas only 11/150 patients with MM exhibited two populations. Patients with AL exhibited an increased cluster of differentiation (CD)19 expression compared with patients with MM, 4.5% (0.1–80.9%) vs. 1.6% (0.1–33.6%; P<0.001) and reduced CD138, with 90.8% (30.4–99.9%) vs. 95.0% (40.7–100%; P=0.006) and CD56, with 61.0% (1.5–99.2%) vs. 98.3% (0.1–100%; P<0.001) expression in malignant PCs. Light chain restriction was identified in all patients with AL, and the proportion of λ light chain restriction was 72.5%. The immunophenotypic characteristics of patients with AL demonstrated by flow cytometry were different compared with the characteristics of patients with MM in the number and composition of plasma cells, and the intracellular and extracellular expression of antigens. These differences may be associated with a less malignant phenotype of clonal PCs in AL than MM.

The Assessment of CD56 and CD117 Expressions at the Time of the Diagnosis in Multiple Myeloma Patients

Objective:

The purpose of this study is to investigate the relationship between the CD56 and CD117 expressions and the clinical and laboratory findings in multiple myeloma (MM) patients.

Materials and Methods:

Analyses of multiparametric flow cytometry data obtained from the diagnostic bone marrow aspirations of a total of 34 newly diagnosed MM patients were assessed retrospectively. CD56 and CD117 expressions of the patients were compared with their stages and clinical parameters. The staging was performed according to the International Staging System (ISS).

Results:

Of the patients, 58.8% had ISS stage 1-2 MM while 41.2% had stage 3 MM. The number of CD56-positive patients was 29, whereas the number of CD117-positive patients was 13. There was no statistical difference between the CD56 and CD117 expressions and extramedullary involvement and lytic bone lesions. The median beta-2 microglobulin level was higher in the CD117-negative group (p=0.047). CD56 and CD117 expression levels were found to be lower in advanced-stage patients than in early-stage ones (p=0.026 and p=0.017). The lactate dehydrogenase (LDH) levels were high in advanced-stage patients, and an inverse relationship was found between LDH level and CD117 expression.

Conclusion:

Our findings that the CD56 and CD117 expression levels are lower in advanced stages than earlier stages and that LDH level and CD117 expression have an inverse relationship in patients with newly diagnosed MM suggest that CD56 and CD117 expressions may be prognostic markers for MM.

The effect of microenvironmental factors on the development of myeloma cells

Multiple myeloma (MM) is a clonal B-cell malignancy characterized by the accumulation of monoclonal plasma cells (PCs) in the bone marrow and other tissues. Although there are several new therapies, MM remains fatal. The interaction between MM cells and the bone marrow microenvironment promotes drug resistance and cancer cells survival. In our present work, we compared the antigen expression pattern of normal and pathological PCs and investigated the possible connections between various surface receptors, adhesion molecules, and recurrent genetic aberrations. We showed that the expression of CD29, CD27, and CD81 is lower in MM cells than in normal PCs. We found correlation of chromosome 11 hyperdiploidity and the decrease of CD27 expression. We demonstrated that MM cells with CD20 positivity also have CD28 expression. Multiple myeloma patients with active CD29 showed better response to treatment. Our results suggest that these changes may result in an alteration of the interaction between stromal cell and MM cell facilitating cell survival and the development of a more aggressive and resistant phenotype.

Atypical immunoglobulin light chain amyloidosis: Spontaneous vertebral compression fracture, liver involvement, and bone marrow involvement report of 3 cases and review of the literature

BACKGROUND

Primary immunoglobulin light chain amyloidosis (AL amyloidosis) is a plasma cell disorder which mainly affects heart, kidneys, liver, and peripheral nervous system. Cases of atypical AL amyloidosis presented as spontaneous vertebral compression fractures have been rarely reported, and data about the management and clinical outcomes of the patients are scarce.

METHODS

Herein, we present 3 new cases of AL amyloidosis with spontaneous vertebral compression fracture and review 13 cases retrieved from the literature.

RESULTS

Moreover, we observed overrepresentations of liver involvement and bone marrow involvement in AL amyloidosis with spontaneous vertebral compression fracture.

CONCLUSION

We believe that better awareness of the rare clinical presentation as spontaneous vertebral compression fracture of AL amyloidosis can facilitate earlier diagnosis and earlier treatment.

Hydroxyapatite/Collagen Composite Is a Reliable Material for Malar Augmentation

PURPOSE

To evaluate the long-term results of cheekbone augmentation using porous hydroxyapatite granules mixed with microfibrillar collagen in a large group of patients.

MATERIALS AND METHODS

Four hundred thirty patients who underwent zygomatic augmentation and intermaxillary osteotomy were evaluated clinically, radiologically, and histologically.

RESULTS

Complications were found in 13 patients (1.56%). There were no relevant radiologic differences in prosthesis volume after 1 month (T1) or after 24 months (T2) in any patient; there were no clinically relevant differences in 110 patients after 36 months. At T1, the prosthesis had a granular structure and the granules had not migrated; at T2, the prosthesis was staunchly adhering to the underlying bone. Over time, the radiopacity of the material increased. Histologic results of 19 biopsy specimens obtained from 8 patients 2 years after the procedure showed prominent ossification with low inflammation, confirming new bone formation over time. According to the visual analog scale, the patients were generally satisfied with the aspects that were considered.

CONCLUSION

Hydroxyapatite and collagen composite used during malarplasty produced a successful outcome. Its main drawback is a learning curve that is longer than for more frequently used implantable biomaterials.

Case 2-2016. An 84-Year-Old Woman with Chest Pain, Dyspnea, and a Rash

An 84-year-old woman was admitted to the hospital because of chest pain, respiratory distress, and a purpuric rash. Initial chest imaging showed bilateral patchy and confluent opacities, a finding consistent with pulmonary edema. A diagnostic procedure was performed.

Absence of both CD56 and CD117 expression on malignant plasma cells is related with a poor prognosis in patients with newly diagnosed multiple myeloma

We retrospectively evaluated the association between the expression of CD56 and CD117 on neoplastic plasma cells and patients prognosis in 50 newly diagnosed multiple myeloma (MM) patients. The overall survival (OS) was measured and Cox proportional hazards model was used to evaluate CD56 and CD117 as possible prognostic factors for OS. CD56+ and CD117+ were detected in 74% and 32% multiple myeloma cases, respectively. In Kaplan-Meier analysis, CD56 and CD117 expression demonstrated potential prognostic impacts and were associated with longer OS (CD56: p=0.004, CD117: p=0.022), absence of both of them showed significantly shorter OS (p=0.046 compared to CD56+/CD117+ group, p=0.014 compared to CD56-/CD117+ or CD56+/CD117- group). Multivariate analysis showed that CD56 was independently prognostic of longer OS (p=0.012). After induction chemotherapy, overall response rates (ORR) was higher in CD56-positive group compared to CD56-negative group (70.6% versus 30.0%, p=0.024), however, there was no difference between CD117-positive and CD117-negative group (69.2% versus 58.1%, p=0.448). This study demonstrated the prognostic value of CD56 and CD117 in patients with newly diagnosed MM patients. Absence of both of them was associated with the poorest prognosis.

Inhibition of Neurosphere Formation in Neural Stem/Progenitor Cells by Acrylamide

Previous studies showed that transplantation of cultured neural stem/progenitor cells (NSPCs) could improve functional recovery for various neurological diseases. This study aims to develop a stem cell-based model for predictive toxicology of development in the neurological system after acrylamide exposure. Treatment of mouse (KT98/F1B-GFP) and human (U-1240 MG/F1B-GFP) NSPCs with 0.5 mM acrylamide resulted in the inhibition of neurosphere formation (definition of self-renewal ability in NSPCs), but not inhibition of cell proliferation. Apoptosis and differentiation of KT98 (a precursor of KT98/F1B-GFP) and KT98/F1B-GFP are not observed in acrylamide-treated neurospheres. Analysis of secondary neurosphere formation and differentiation of neurons and glia illustrated that acrylamide-treated KT98 and KT98/F1B-GFP neurospheres retain the NSPC properties, such as self-renewal and differentiation capacity. Correlation of acrylamide-inhibited neurosphere formation with cell-cell adhesion was observed in mouse NSPCs by live cell image analysis and the presence of acrylamide. Protein expression levels of cell adhesion molecules [neural cell adhesion molecule (NCAM) and N-cadherin] and extracellular signal-regulated kinases (ERK) in acrylamide-treated KT98/F1B-GFP and U-1240 MG/F1B-GFP neurospheres demonstrated that NCAM decreased and phospho-ERK (pERK) increased, whereas expression of N-cadherin remained unchanged. Analysis of AKT (protein kinase B, PKB)/β-catenin pathway showed decrease in phospho-AKT (p-AKT) and cyclin D1 expression in acrylamide-treated neurospheres of KT98/F1B-GFP. Furthermore, PD98059, an ERK phosphorylation inhibitor, attenuated acrylamide-induced ERK phosphorylation, indicating that pERK contributed to the cell proliferation, but not in neurosphere formation in mouse NSPCs. Coimmunoprecipitation results of KT98/F1B-GFP cell lysates showed that the complex of NCAM and fibroblast growth factor receptor 1 (FGFR1) is present in the neurosphere, and the amount of this complex decreases after acrylamide treatment. Our results reveal that acrylamide inhibits neurosphere formation through the disruption of the neurosphere architecture in NSPCs. The downregulation of cell-cell adhesion resulted from decreasing the levels of NCAM as well as the formation of NCAM/ FGFR complex.

A unique population of IgG-expressing plasma cells lacking CD19 is enriched in human bone marrow

Healthy human BM is enriched for PC lacking CD19 that express a prosurvival and distinctly mature phenotype. CD19− PC resist mobilization into blood during immune responses after vaccination as well as B-cell depletion with rituximab.

Characterization of a new human plasma cell leukemia cell line UHKT-944

OBJECTIVE

A new interleukin-6 (IL-6)-dependent plasma cell leukemia cell line UHKT-944 was established from bone marrow cells derived from a 55-yr-old man with plasma cell leukemia.

RESULTS

The cell line possesses phenotypic characteristics of plasma cells including the production of a monoclonal immunoglobulin IgA1-kappa. VH3-9 region of IgVH genes was rearranged and somatically hypermutated. The UHKT-944 cells were found to be negative for most of tested B-cell, T-cell, and myeloid markers. According to cytogenetic analysis, the cells were classified as near tetraploid with several numerical and structural abnormalities including the t(14;20) involving IgH locus.

CONCLUSION

The established permanent plasma cell leukemia cell line is a suitable model for the study of cellular and molecular mechanisms of pathogenesis of this rare malignant disease.

CD56 Expression in Odontogenic Cysts and Tumors

Background and aims. Odontogenic cysts and tumors have a wide spectrum of clinical characteristics that lead to the different management strategies. Since definite diagnosis is difficult in some cases, it has been suggested that CD56 may be a candidate marker for definitive diagnosis of some odontogenic tumors. The present study was designed to examine CD56 expression in lesions with histopathological similarities.

Materials and methods. In this cross-sectional, analytical study the subjects were 22 ameloblastomas, 13 dentigerous cysts, 10 keratocystic odontogenic tumors (KCOT), 4 adenomatoid odontogenic tumors (AOT), 3 orthokeratinized odonto-genic cysts, 3 calcifying odontogenic cysts (COC) and one glandular odontogenic cyst (GOC). All the samples were examined for CD56 immunoreactivity. Data were analyzed using chi-square test.

Results. Twenty cases (91%) of ameloblastomas, 3 (75%) AOT, 4 (40%) KCOT and one case of GOC were positive for CD56. None of the dentigerous cysts, COC and orthokeratinized odontogenic cysts was CD56-positive. There was a significant difference in the CD56 expression between ameloblastoma and dentigerous cyst, as well as COC. Also, KCOT showed significantly higher expression than orthokeratinized odontogenic cyst.

Conclusion. In this study CD56 expression was limited to the odontogenic tumors and more aggressive cystic lesions. This marker can be a useful aid for distinguishing cysts and tumors from similar lesions.

Bone marrow graft-versus-host disease: evaluation of its clinical impact on disrupted hematopoiesis after allogeneic hematopoietic stem cell transplantation

Idiopathic cytopenias are frequently observed in patients after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We have previously reported the effect of graft-versus-host disease (GVHD) on bone marrow (BM) in murine models, indicating that the osteoblast injury mediated by donor T cells was associated with bone marrow suppression and delayed immune reconstitution. In this study, we prospectively evaluated the relevance of these findings in 51 patients. Patients with chronic GVHD manifested the loss of osteoblasts, contributing to cytopenic symptoms (P = .0427 compared with patients without cytopenic symptoms). The loss of osteoblasts was significantly associated with the extensive type of chronic GVHD (P = .012), and flow cytometric analyses revealed lower numbers of CD19(+) B cells and a significantly increased CD4 to CD8 ratio (P = .0002) in these patients. Our data, for the first time to our knowledge, summarize the detailed analyses of the effect of GVHD on BM in the clinical allo-HSCT patients.

Extramedullary plasmacytoma of the trachea

Extramedullary plasmacytomas are plasma cell tumors that occur outside the bone marrow. They constitute around 4 % of all plasma cell neoplasms. The most common site of extramedullary plasmacytoma is the upper aerodigestive tract-nasal cavity, paranasal sinuses and oronasopharynx. We are presenting a case of extramedullary plasmacytoma of the trachea. Trachea is an extremely rare site of plasmacytoma. When extraosseous plasmacytoma occur in uncommon sites, the distinction from B cell lymphomas showing extensive plasmacytic differentiation can be difficult and diagnostically challenging.

Monoclonal antibody-based immunotherapy for multiple myeloma

Multiple myeloma (MM) is a life-threatening hematological malignancy. High-dose chemotherapy followed by autologous stem cell transplantation is a relatively effective treatment, but disease recurrence remains a major obstacle. Allogeneic transplantation may result in durable responses and cure due to antitumor immunity mediated by donor lymphocytes. However, morbidity and mortality related to graft-versus-host disease remain a challenge. Recent advances in understanding the interaction between the immune system of the patient and the malignant cells are influencing the design of clinically more efficient study protocols for MM. This review will focus on MM antigens and their specific antibodies. These monoclonal antibodies are an attractive therapeutic tool for MM humoral immunotherapy, with most promising preclinical results.

EuroFlow antibody panels for standardized n-dimensional flow cytometric immunophenotyping of normal, reactive and malignant leukocytes

Most consensus leukemia & lymphoma antibody panels consist of lists of markers based on expert opinions, but they have not been validated. Here we present the validated EuroFlow 8-color antibody panels for immunophenotyping of hematological malignancies. The single-tube screening panels and multi-tube classification panels fit into the EuroFlow diagnostic algorithm with entries defined by clinical and laboratory parameters. The panels were constructed in 2-7 sequential design-evaluation-redesign rounds, using novel Infinicyt software tools for multivariate data analysis. Two groups of markers are combined in each 8-color tube: (i) backbone markers to identify distinct cell populations in a sample, and (ii) markers for characterization of specific cell populations. In multi-tube panels, the backbone markers were optimally placed at the same fluorochrome position in every tube, to provide identical multidimensional localization of the target cell population(s). The characterization markers were positioned according to the diagnostic utility of the combined markers. Each proposed antibody combination was tested against reference databases of normal and malignant cells from healthy subjects and WHO-based disease entities, respectively. The EuroFlow studies resulted in validated and flexible 8-color antibody panels for multidimensional identification and characterization of normal and aberrant cells, optimally suited for immunophenotypic screening and classification of hematological malignancies.

Novel strategies for immunotherapy in multiple myeloma: previous experience and future directions

Multiple myeloma (MM) is a life-threatening haematological malignancy for which standard therapy is inadequate. Autologous stem cell transplantation is a relatively effective treatment, but residual malignant sites may cause relapse. Allogeneic transplantation may result in durable responses due to antitumour immunity mediated by donor lymphocytes. However, morbidity and mortality related to graft-versus-host disease remain a challenge. Recent advances in understanding the interaction between the immune system of the patient and the malignant cells are influencing the design of clinically more efficient study protocols for MM. Cellular immunotherapy using specific antigen-presenting cells (APCs), to overcome aspects of immune incompetence in MM patients, has received great attention, and numerous clinical trials have evaluated the potential for dendritic cell (DC) vaccines as a novel immunotherapeutic approach. This paper will summarize the data investigating aspects of immunity concerning MM, immunotherapy for patients with MM, and strategies, on the way, to target the plasma cell more selectively. We also include the MM antigens and their specific antibodies that are of potential use for MM humoral immunotherapy, because they have demonstrated the most promising preclinical results.

Myeloma-induced alloreactive T cells arising in myeloma-infiltrated bones include double-positive CD8+CD4+ T cells: evidence from myeloma-bearing mouse model

The graft-versus-myeloma (GVM) effect represents a powerful form of immune attack exerted by alloreactive T cells against multiple myeloma cells, which leads to clinical responses in multiple myeloma transplant recipients. Whether myeloma cells are themselves able to induce alloreactive T cells capable of the GVM effect is not defined. Using adoptive transfer of T naive cells into myeloma-bearing mice (established by transplantation of human RPMI8226-TGL myeloma cells into CD122(+) cell-depleted NOD/SCID hosts), we found that myeloma cells induced alloreactive T cells that suppressed myeloma growth and prolonged survival of T cell recipients. Myeloma-induced alloreactive T cells arising in the myeloma-infiltrated bones exerted cytotoxic activity against resident myeloma cells, but limited activity against control myeloma cells obtained from myeloma-bearing mice that did not receive T naive cells. These myeloma-induced alloreactive T cells were derived through multiple CD8(+) T cell divisions and enriched in double-positive (DP) T cells coexpressing the CD8αα and CD4 coreceptors. MHC class I expression on myeloma cells and contact with T cells were required for CD8(+) T cell divisions and DP-T cell development. DP-T cells present in myeloma-infiltrated bones contained a higher proportion of cells expressing cytotoxic mediators IFN-γ and/or perforin compared with single-positive CD8(+) T cells, acquired the capacity to degranulate as measured by CD107 expression, and contributed to an elevated perforin level seen in the myeloma-infiltrated bones. These observations suggest that myeloma-induced alloreactive T cells arising in myeloma-infiltrated bones are enriched with DP-T cells equipped with cytotoxic effector functions that are likely to be involved in the GVM effect.

Neural cell adhesion molecule potentiates the growth of murine melanoma via β-catenin signaling by association with fibroblast growth factor receptor and glycogen synthase kinase-3β

The neural cell adhesion molecule (NCAM) was recently shown to be involved in the progression of various tumors with diverse effects. We previously demonstrated that NCAM potentiates the cellular invasion and metastasis of melanoma. Here we further report that the growth of melanoma is obviously retarded when the expression of NCAM is silenced. We found that the proliferation of murine B16F0 melanoma cells, their colony formation on soft agar, and growth of transplanted melanoma in vivo are clearly inhibited by the introduction of NCAM siRNA. Interestingly, change of NCAM expression level is shown to regulate the activity of Wnt signaling molecule, β-catenin, markedly. This novel machinery requires the function of FGF receptor and glycogen synthase kinase-3β but is independent of the Wnt receptors, MAPK-Erk and PI3K/Akt pathways. In addition, NCAM is found to form a functional complex with β-catenin, FGF receptor, and glycogen synthase kinase-3β. Moreover, up-regulation of NCAM140 and NCAM180 appears more potent than NCAM120 in activation of β-catenin, suggesting that the intracellular domain of NCAM is required for facilitating the β-catenin signaling. Furthermore, the melanoma cells also exhibit distinct differentiation phenotypes with the NCAM silencing. Our findings reveal a novel regulatory role of NCAM in the progression of melanoma that might serve as a new therapeutic target for the treatment of melanoma.