Low dose venetoclax as a single agent treatment of plasma cell malignancies harboring t(11;14).

Approximately 20% of newly diagnosed multiple myeloma (NDMM) patients harbor t(11;14), a marker of inferior prognosis, resulting in up-regulation of CCND1. These patients respond to BCL2 inhibitor experimental drug venetoclax. Furthermore, t(11;14) is reported to be associated with increased BCL2/MCL1 ratio. We investigated the use of venetoclax (400 mg daily) in a cohort of 25 multiple myeloma (MM) and AL-amyloidosis patients harboring t(11;14) and assessed safety and efficacy. Efficacy was assessed by response rate (RR) and time on treatment. Furthermore, immunohistochemistry (IHC), for BCL2 family member expression was assessed at diagnosis and relapse in the venetoclax-treated group and analyzed for correlation with clinical RR. Additionally, patient material from venetoclax non-treated group including non-t(11;14) diagnosis (n = 27), t(11;14) diagnosis (n = 17), t(11;14) relapse (n = 7), hyperdiploidy (n = 6) and hyperdiploidy + t(11;14) (n = 6) was used for RNA sequencing (RNASeq) and validation by qPCR. Venetoclax treatment in t(11;14) patients demonstrated manageable safety and promising efficacy. Partial responses or better were observed in eleven patients (44%). Responding patients had significantly higher BCL2/MCL1 (p = 0.031) as well as BCL2/BCL-XL (p = 0.021) ratio, regardless of time of measurement before venetoclax treatment. Furthermore, an IRF5 motif was enriched (p < .001) in the downregulated genes in t(11;14) relapses vs diagnoses. The RR with single agent venetoclax was 71% in AL-amyloidosis and 33% in MM, and IHC proved useful in prediction of treatment outcome. We could also demonstrate possible resistance mechanisms of t(11;14), downregulation of IRF5 targeted genes, which can be exploited for therapeutic advantages.

Active enhancer and chromatin accessibility landscapes chart the regulatory network of primary multiple myeloma.

Multiple myeloma (MM) is an aggressive cancer that originates from antibody-secreting plasma cells. Although genetically and transcriptionally well characterized, the aberrant gene regulatory networks that underpin this disease remain poorly understood. Here, we mapped regulatory elements, open chromatin, and transcription factor (TF) footprints in primary MM cells. In comparison with normal antibody-secreting cells, MM cells displayed consistent changes in enhancer activity that are connected to superenhancer (SE)-mediated deregulation of TF genes. MM cells also displayed widespread decompaction of heterochromatin that was associated with activation of regulatory elements and in a major subset of patients' deregulation of the cyclic adenosine monophosphate pathway. Finally, building SE-associated TF-based regulatory networks allowed identification of several novel TFs that are central to MM biology. Taken together, these findings significantly add to our understanding of the aberrant gene regulatory network that underpins MM.

Translocation (11;14) in newly diagnosed multiple myeloma, time to reclassify this standard risk chromosomal aberration?

OBJECTIVES: The most common translocation in multiple myeloma (MM) is t(11;14)(q13;q32), and its importance as prognostic factor has been controversial. The aim was to analyze its prognostic value. METHOD: In this retrospective study of 469 newly diagnosed myeloma patients, outcomes in patients with (11;14) and standard risk (t(11;14)SR) or high risk (t(11;14)HR) cytogenetics were compared to outcomes of patients without t(11;14) and SR (non-t(11;14)SR) or HR (non-t(11;14)HR), respectively. RESULTS: Overall progression-free survival (PFS) was shorter in t(11;14)SR than non-t(11;14)SR (median 28.9 vs 35.3 months); however, the difference was not significant (P = .2). Overall survival (OS) did not differ significantly between the groups. In the subgroup of patients that did not receive high-dose treatment, PFS was shorter for t(11;14)SR compared to non-t(11;14)SR, 10.6 vs 24.6 months (P = .01). Although OS were shorter for t(11,14)SR compared to non-t(11;14)SR (5-year OS 41.7% vs 63.8%), the difference was not significant (P = .1). In HDT patients, no significant difference was observed for OS or PFS between those with or without t(11;14). CONCLUSION: This study shows that t(11;14) is associated with poorer outcome in MM, particularly in non-high-dose-treated SR patients. It should be considered an intermediate or high-risk marker in these patients.

Linked-read whole-genome sequencing resolves common and private structural variants in multiple myeloma.

Multiple myeloma (MM) is an incurable and aggressive plasma cell malignancy characterized by a complex karyotype with multiple structural variants (SVs) and copy-number variations (CNVs). Linked-read whole-genome sequencing (lrWGS) allows for refined detection and reconstruction of SVs by providing long-range genetic information from standard short-read sequencing. This makes lrWGS an attractive solution for capturing the full genomic complexity of MM. Here we show that high-quality lrWGS data can be generated from low numbers of cells subjected to fluorescence-activated cell sorting (FACS) without DNA purification. Using this protocol, we analyzed MM cells after FACS from 37 patients with MM using lrWGS. We found high concordance between lrWGS and fluorescence in situ hybridization (FISH) for the detection of recurrent translocations and CNVs. Outside of the regions investigated by FISH, we identified >150 additional SVs and CNVs across the cohort. Analysis of the lrWGS data allowed for resolution of the structure of diverse SVs affecting the MYC and t(11;14) loci, causing the duplication of genes and gene regulatory elements. In addition, we identified private SVs causing the dysregulation of genes recurrently involved in translocations with the IGH locus and show that these can alter the molecular classification of MM. Overall, we conclude that lrWGS allows for the detection of aberrations critical for MM prognostics and provides a feasible route for providing comprehensive genetics. Implementing lrWGS could provide more accurate clinical prognostics, facilitate genomic medicine initiatives, and greatly improve the stratification of patients included in clinical trials.

Impact of chromosome 13 deletion and plasma cell load on long-term survival of patients with multiple myeloma undergoing autologous transplantation.

High-dose therapy (HDT) followed by autologous stem cell transplantation (ASCT) is the most common treatment for patients under 65 years of age with multiple myeloma (MM). In this study, we present a retrospective analysis of the prognostic impact of different factors in patients who have received this treatment as first line therapy in our centre. Abnormalities in chromosome 13 were identified by fluorescence in situ hybridization at the time of diagnosis. The median overall survival (OS) and progression-free survival (PFS) from transplantation time in the whole group of 193 patients were 90 and 48 months respectively. The median follow-up was 65 months (range: 6-186 months). The complete remission (CR) rate in patients with and without del(13) was 31 and 40% respectively whereas the median OS in patients with del(13) was 58 months but not reached in patients without del(13) (p=0.006). The PFS was 26 months in patients with del(13) and 84 months in those without del(13) (p=0.001). The transplantation related mortality was 2.5% both in the absence and presence of del(13). Patients who achieved CR following ASCT had longer OS and PFS when compared to those who only achieved partial remission. Thus, this study confirms the role of del(13) as a marker of poor prognosis. Multivariate analysis showed that the existence of del(13) was the only single independent factor effecting survival (p=0.001). In patients without del(13), the prognostic impact was even stronger when combined with the plasma cell load in the bone marrow (p=0.020), whereas the plasma cell load had no effect on survival of patients with del(13). Overall, the absence of del(13) in combination with low plasma cell infiltration at diagnosis predicts the best survival.

Characterization of genetic changes in MCL by interphase FISH on tissue sections.

Mantle cell lymphoma is a clinically heterogeneous disease, where further elucidation of pathogenetic mechanisms and better prognostic information is required. We evaluated genetic aberrations by interphase FISH on tissue sections or cytological material in 38 samples from 30 MCL patients, including 5 cases with cyclin D1 3'UTR low, which previously has been associated to unfavourable prognosis. The findings have been related to proliferation and clinical outcome. All but one of MCL showed t(11:14) translocation and in 22/30 samples taken at diagnosis or first relapse, one or several cytogenetic changes were detected; 11 deletions of ATM, 13 p53 deletions, 8 numerical c-myc-aberrations and 6 delp16. All but one MCL with low cyclin D1 3'UTR had additional cytogenetic changes, however no particular genetic change was strictly associated with this MCL variant. One fourth of MCL had none of the investigated additional aberrations and these tumours were in general less proliferative and some of these patients had a very long survival.

Deletion of Chromosomal Region 8p21 Confers Resistance to Bortezomib and Is Associated with Upregulated Decoy TRAIL Receptor Expression in Patients with Multiple Myeloma.

Loss of the chromosomal region 8p21 negatively effects survival in patients with multiple myeloma (MM) that undergo autologous stem cell transplantation (ASCT). In this study, we aimed to identify the immunological and molecular consequences of del(8)(p21) with regards to treatment response and bortezomib resistance. In patients receiving bortezomib as a single first line agent without any high-dose therapy, we have observed that patients with del(8)(p21) responded poorly to bortezomib with 50% showing no response while patients without the deletion had a response rate of 90%. In vitro analysis revealed a higher resistance to bortezomib possibly due to an altered gene expression profile caused by del(8)(p21) including genes such as TRAIL-R4, CCDC25, RHOBTB2, PTK2B, SCARA3, MYC, BCL2 and TP53. Furthermore, while bortezomib sensitized MM cells without del(8)(p21) to TRAIL/APO2L mediated apoptosis, in cells with del(8)(p21) bortezomib failed to upregulate the pro-apoptotic death receptors TRAIL-R1 and TRAIL-R2 which are located on the 8p21 region. Also expressing higher levels of the decoy death receptor TRAIL-R4, these cells were largely resistant to TRAIL/APO2L mediated apoptosis. Corroborating the clinical outcome of the patients, our data provides a potential explanation regarding the poor response of MM patients with del(8)(p21) to bortezomib treatment. Furthermore, our clinical analysis suggests that including immunomodulatory agents such as Lenalidomide in the treatment regimen may help to overcome this negative effect, providing an alternative consideration in treatment planning of MM patients with del(8)(p21).

Constitutional inv(3) in myelodysplastic syndromes.

The constitutional pericentric inversion on chromosome 3, inv(3), is rarely found in a normal population. The aim of our study was to investigate its possible link to hematologic malignancy. Chromosomes from bone marrow cells in 890 patients with hematologic disorders were analyzed with the Q-banding technique. Thirty-four patients had inv(3) (3.8%). In 241 patients with myelodysplastic syndromes the frequency was 6.2% as opposed to 2.9% in the remaining 649 patients (p=0.02). The increased frequency of inv(3) in patients with myelodysplastic syndromes indicates that inv(3) could be a risk factor for the development of the disease.