Molecular profiling in multiple myeloma

Multiple Myeloma (MM) is a malignant plasma cell disorder accounting for 1% of all malignant diseases and 10% of hematological malignancies. The annual incidence world-wide of MM is approximately 0.4 to 5 per 100.000, with high incidence rates in North America, Australia/New Zealand, Northern Europe, and Western Europe compared with Asian countries. Within the United States, the incidence in African Americans is about double that in Caucasians, whereas persons of Japanese and Chinese origin have lower rates. In the Netherlands the annual incidence of MM is 5 per 100.000 and increases progressively with age, the median age of diagnosis is 70 years. MM is characterized by clonal expansion of malignant plasma cells in the bone marrow. The myeloma plasma cell is a post-germinal centre plasma cell which has undergone somatic hypermutation and immunoglobulin class switching. MM cells secrete a monoclonal protein (M-protein) which can be detected in serum and/or urine. The M-protein is IgG in 50% of patients, and IgA in 30% of patients or consists of light chain (15%). In rare cases, secretion of IgD (1%–2%), IgM (0.2%), or IgE (even less frequent), or absence of secretion (non-secretory MM) is found. Osteolytic bone lesions are the hallmark of MM. Other characteristic clinical features include renal injury, anemia, hypercalcemia and immunodeficiency with recurrent infections. These features may result directly from mass accumulation of plasma cells in tissues (plasmacytomas) or indirectly from effects of the M-protein and/or cytokines secreted by the plasma cells. Furthermore a high level of M-protein can cause hyperviscosity, renal failure and neuropathy

Influence of genetic polymorphisms in CYP3A4, CYP3A5, GSTP1, GSTM1, GSTT1 and MDR1 genes on survival and therapy-related toxicity in multiple myeloma

We investigated the role of single nucleotide polymorphisms in genes encoding for drug-metabolizing enzymes in 209 newly diagnosed multiple myeloma patients included in a clinical trial comparing single with double intensive therapy. We observed no significant association between polymorphisms in CYP3A4, CYP3A5, MDR1, GSTM1 and GSTT1 and outcome either after treatment with induction chemotherapy or after high-dose therapy

A gene expression based predictor for high risk myeloma treated with intensive therapy and autologous stem cell rescue

Myeloma is characterized by a highly variable clinical outcome. Despite the effectiveness of high-dose therapy, 15% of patients relapse within 1 year. We show that these cases also have a significantly shorter post-relapse survival compared to the others (median 14.9 months vs. 40 months, p = 8.03 × 10(- 14)). There are no effective approaches to define this potentially distinct biological group such that treatment could be altered. In this work a series of uniformly treated patients with myeloma were used to develop a gene expression profiling (GEP)-based signature to identify this high risk clinical behavior. Gene enrichment analyses applied to the top differentially expressed genes showed a significant enrichment of epigenetic regulators as well as "stem cell" myeloma genes. A derived 17-gene signature effectively identifies patients at high risk of early relapse as well as impaired overall survival. Integrative genomic analyses showed that epigenetic mechanisms may play an important role on transcription of these genes

Phase II study of carfilzomib, thalidomide, and low-dose dexamethasone as induction and consolidation in newly diagnosed, transplant eligible patients with multiple myeloma; the Carthadex trial

This is a phase II dose escalation trial of carfilzomib in combination with thalidomide and dexamethasone for induction and consolidation in transplant-eligible patients with newly diagnosed multiple myeloma (NDMM). The results of four dose levels are reported. Induction therapy consisted of four cycles of carfilzomib 20/27 mg/m2 (n=50), 20/36 mg/m2 (n=20), 20/45 mg/m2 (n=21), and 20/56 mg/m2 (n=20) on days 1, 2, 8, 9, 15, 16 of a 28-day cycle; thalidomide 200 mg on day 1 through 28 and dexamethasone 40 mg weekly. Induction therapy was followed by high-dose melphalan and autologous stem cell transplantation and consolidation therapy with four cycles of carfilzomib, thalidomide and dexamethasone in the same schedule except a lower dose of thalidomide (50 mg). Very good partial response rate or better and complete response rate or better after ind

Transcriptome-wide association study of multiple myeloma identifies candidate susceptibility genes

Background: While genome-wide association studies (GWAS) of multiple myeloma (MM) have identified variants at 23 regions influencing risk, the genes underlying these associations are largely unknown. To identify candidate causal genes at these regions and search for novel risk regions, we performed a multi-tissue transcriptome-wide association study (TWAS). Results: GWAS data on 7319 MM cases and 234,385 controls was integrated with Genotype-Tissue Expression Project (GTEx) data assayed in 48 tissues (sample sizes, N = 80–491), including lymphocyte cell lines and whole blood, to predict gene expression. We identified 108 genes at 13 independent regions associated with MM risk, all of which were in 1 Mb of known MM GWAS risk variants. Of these, 94 genes, located in eight regions, had not previously been considered as a candidate gene for that locus. Conclusions: Our findings highlight the value of leveraging expression data from multiple tissues to identify candidate genes responsible for GWAS associations which provide insight into MM tumorigenesis. Among the genes identified, a number have plausible roles in MM biology, notably APOBEC3C, APOBEC3H, APOBEC3D, APOBEC3F, APOBEC3G, or have been previously implicated in other malignancies. The genes identified in this TWAS can be explored for follow-up and validation to further understand their role in MM biology

Identification of multiple risk loci and regulatory mechanisms influencing susceptibility to multiple myeloma

Genome-wide association studies (GWAS) have transformed our understanding of susceptibility to multiple myeloma (MM), but much of the heritability remains unexplained. We report a new GWAS, a meta-analysis with previous GWAS and a replication series, totalling 9974 MM cases and 247,556 controls of European ancestry. Collectively, these data provide evidence for six new MM risk loci, bringing the total number to 23. Integration of information from gene expression, epigenetic profiling and in situ Hi-C data for the 23 risk loci implicate disruption of developmental transcriptional regulators as a basis of MM susceptibility, compatible with altered B-cell differentiation as a key mechanism. Dysregulation of autophagy/apoptosis and cell cycle signalling feature as recurrently perturbed pathways. Our findings provide further insight