Bergsagel, P. Leif

Key PointsWe identified CRBN-binding proteins and confirmed recent work implicating the Ikaros transcription factors as important members. Low IZKF1 levels predict lack of IMiD responsiveness and shorter OS; IZKF1 expression is a potential predictive biomarker for clinic application.

The celebration of the 50th anniversary of the founding of the American Society of Clinical Oncology provides the occasion to review the progress that has been made in the biology and treatment of multiple myeloma. With the advent of melphalan and cyclophosphamide in the early 1960s the median survival of patients with multiple myeloma more than doubled from 10 months to approximately 24 months. Throughout multiple clinical trials in the 1970s and 1980s, melphalan and prednisone remained the gold standard, with a 3-year survival of 42%. The use of high-dose melphalan with autologous hematopoietic stem cell support provided an incremental advance in the 1990s. The outlook for patients was dramatically improved in the 2000s with the introduction of thalidomide analogs and proteasome inhibitors, so that the 3-year survival of patients treated in 2008 with melphalan and prednisone had increased to 66%. The 2010s are dominated by studying the optimal combination, sequence, and duration of therapies. These clinical advances have occurred along with our evolving understanding of the molecular pathogenesis of myeloma. Myeloma can be divided into two main groups: hyperdiploid, with multiple trisomies of odd-numbered chromosomes, and nonhyperdiploid, with recurrent immunoglobulin heavy chain gene translocations. Disease progression is associated with rearrangements of MYC, the most common mutation in myeloma, present in nearly half of patients. Genomic studies have highlighted marked subclonal heterogeneity that poses one of the main challenges to successful control of the disease. This problem will be addressed in future studies in the 2020s, which will include a focus on immunologic approaches such as monoclonal antibodies, checkpoint inhibitors, engineered T-cells, and novel immunomodulators.

Significance We show that DNA double-strand breaks (DSBs) can be repaired by insertion of 50- to 1,000-bp sequences termed “templated-sequence insertions” (TSIs) derived from distant regions of the genome. Additional experiments indicate that the source of template for repair was primarily nuclear RNA. This mode of DNA-DSB repair by insertion is not restricted to experimentally produced breaks but also occurs at the site of spontaneous DNA DSBs in human cells. These TSIs are polymorphic in the human genome, suggesting that some TSIs occur in germ cells or embryos. Recognition of these TSIs is important in interpreting structural variations in short-read sequencing studies and provides additional polymorphic markers for population and evolution studies. This error-prone form of DNA repair may play a role in genetic diseases.

Key PointsCD28 delivers a pro-survival signal to MM cells via regulation of PI3K/Akt, FoxO3a, and Bim. Blockade of CD28:CD80/CD86 in vivo resensitizes MM cells to chemotherapy and significantly reduces tumor burden.

Key PointsWe describe a novel, druggable pathway that controls myeloma growth through macrophages in the myeloma microenvironment. Macrophages are dominant orchestrators of the inflammatory milieu of the myeloma niche.

Primary IGH translocations involving seven recurrent partner loci and oncogenes are present in about 40% of multiple myeloma tumors. Secondary IGH rearrangements, which occur in a smaller fraction of tumors, usually are complex structures, including insertions or translocations that can involve three chromosomes, and often with involvement of MYC. The main approach to detect IGH rearrangements is interphase—but sometimes metaphase—FISH strategies that use a telomeric variable region probe and a centromeric constant region/ Eα enhancer or 3′ flanking probe to detect a separation of these two probes, or a fusion of these probes with probes located at nonrandom partner sites in the genome. We analyzed 18 myeloma cell lines for detection discrepancies among Vysis, Cytocell, and in‐house IGH probe sets that hybridize with differing sequences in the IGH locus. There were no detection discrepancies for the three telomeric IGH probes, or for unrearranged IGH loci or primary IGH translocations using the centromeric IGH probes. However, the majority of complex IGH rearrangements had detection discrepancies among the three centromeric IGH probes. © 2014 Wiley Periodicals, Inc.

Key Points The tumor microenvironment drives myeloma cell clonogenic growth and self-renewal through GDF15.

Everolimus is an oral raptor mTOR inhibitor and has shown activity in patients with Waldenstrom's macroglobulinemia (WM). This study examines a large cohort of patients with relapsed/refractory WM with long‐term follow up for survival. Patients were eligible if they had measurable disease, a platelet count >75,000 × 106/L, an absolute neutrophil count >1,000 × 106/L. Patients received everolimus 10 mg PO daily and were evaluated monthly. A success was defined as a complete or partial response (PR); minor responses (MR) were recorded and considered to be of clinical benefit. Sixty patients were enrolled and treated. The overall response rate (ORR) was 50% (all PR); the clinical benefit rate including MR or better was 73% (95% CI: 60–84%) with 23% MR. The median time to response for patients who achieved PR was 2 months (range, 1–26). The median duration of response has not been reached and median progression‐free survival (PFS) was 21 months. Grade 3 or higher toxicities (at least possibly related to everolimus) were observed in 67% of patients. The most common grade 3 or 4 toxicities were anemia (27%), leukopenia (22%), and thrombocytopenia (20%). Other nonhematological toxicities were diarrhea (5%), fatigue (8%), stomatitis (8%) and pulmonary toxicity (5%). Everolimus has a high single‐agent activity of 73% including MR, with a progression free survival of 21 months, indicating that this agent is active in relapsed/refractory WM. Am. J. Hematol. 89:237–242, 2014. © 2013 Wiley Periodicals, Inc

Abstract Smoldering multiple myeloma (SMM) bridges the gap between monoclonal gammopathy of undetermined significance (a mostly premalignant disorder) and active multiple myeloma (MM). Until recently, no interventional study in patients with SMM showed improved overall survival (OS) with therapy as compared with observation. A report from the PETHEMA-GEM (Programa Español de Tratamientos en Hematologica) group described both fewer myeloma-related events and better OS among patients with high-risk SMM who were treated with lenalidomide and dexamethasone. This unique study prompted us to review current knowledge about SMM and address the following questions: (1) Are there patients currently defined as SMM who should be treated routinely? (2) Should the definitions of SMM and MM be reconsidered? (3) Has the time come when not treating is more dangerous than treating? (4) Could unintended medical harm result from overzealous intervention? Our conclusion is that those patients with the highest-risk SMM (extreme bone marrow plasmacytosis, extremely abnormal serum immunoglobulin free light chain ratio, and multiple bone lesions detected only by modern imaging) should be reclassified as active MM so that they can receive MM-appropriate therapy and the paradigm of careful observation for patients with SMM can be preserved.