Oncogenic role and target properties of the lysine-specific demethylase KDM1A in chronic lymphocytic leukemia.

In chronic lymphocytic leukemia (CLL), epigenetic alterations are considered to centrally shape the transcriptional signatures that drive disease evolution and underlie its biological and clinical subsets. Characterizations of epigenetic regulators, particularly histone-modifying enzymes, are very rudimentary in CLL. In efforts to establish effectors of the CLL-associated oncogene T-cell leukemia 1A (TCL1A), we identified here the lysine-specific histone demethylase KDM1A to interact with the TCL1A protein in B cells in conjunction with an increased catalytic activity of KDM1A. We demonstrate that KDM1A is upregulated in malignant B cells. Elevated KDM1A and associated gene expression signatures correlated with aggressive disease features and adverse clinical outcomes in a large prospective CLL trial cohort. Genetic Kdm1a knockdown in Eµ-TCL1A mice reduced leukemic burden and prolonged animal survival, accompanied by upregulated p53 and proapoptotic pathways. Genetic KDM1A depletion also affected milieu components (T, stromal, and monocytic cells), resulting in significant reductions in their capacity to support CLL-cell survival and proliferation. Integrated analyses of differential global transcriptomes (RNA sequencing) and H3K4me3 marks (chromatin immunoprecipitation sequencing) in Eµ-TCL1A vs iKdm1aKD;Eµ-TCL1A mice (confirmed in human CLL) implicate KDM1A as an oncogenic transcriptional repressor in CLL which alters histone methylation patterns with pronounced effects on defined cell death and motility pathways. Finally, pharmacologic KDM1A inhibition altered H3K4/9 target methylation and revealed marked anti-B-cell leukemic synergisms. Overall, we established the pathogenic role and effector networks of KDM1A in CLL via tumor-cell intrinsic mechanisms and its impacts in cells of the microenvironment. Our data also provide rationales to further investigate therapeutic KDM1A targeting in CLL.

Characterization of structural, biochemical, pharmacokinetic, and pharmacodynamic properties of the LSD1 inhibitor bomedemstat in preclinical models.

INTRODUCTION: Lysine-specific demethylase 1 (LSD1) is emerging as a critical mediator of tumor progression in metastatic castration-resistant prostate cancer (mCRPC). Neuroendocrine prostate cancer (NEPC) is increasingly recognized as an adaptive mechanism of resistance in mCRPC patients failing androgen receptor axis-targeted therapies. Safe and effective LSD1 inhibitors are necessary to determine antitumor response in prostate cancer models. For this reason, we characterize the LSD1 inhibitor bomedemstat to assess its clinical potential in NEPC as well as other mCRPC pathological subtypes. METHODS: Bomedemstat was characterized via crystallization, flavine adenine dinucleotide spectrophotometry, and enzyme kinetics. On-target effects were assessed in relevant prostate cancer cell models by measuring proliferation and H3K4 methylation using western blot analysis. In vivo, pharmacokinetic (PK) and pharmacodynamic (PD) profiles of bomedemstat are also described. RESULTS: Structural, biochemical, and PK/PD properties of bomedemstat, an irreversible, orally-bioavailable inhibitor of LSD1 are reported. Our data demonstrate bomedemstat has >2500-fold greater specificity for LSD1 over monoamine oxidase (MAO)-A and -B. Bomedemstat also demonstrates activity against several models of advanced CRPC, including NEPC patient-derived xenografts. Significant intra-tumoral accumulation of orally-administered bomedemstat is measured with micromolar levels achieved in vivo (1.2 ± 0.45 µM at the 7.5 mg/kg dose and 3.76 ± 0.43 µM at the 15 mg/kg dose). Daily oral dosing of bomedemstat at 40 mg/kg/day is well-tolerated, with on-target thrombocytopenia observed that is rapidly reversible following treatment cessation. CONCLUSIONS: Bomedemstat provides enhanced specificity against LSD1, as revealed by structural and biochemical data. PK/PD data display an overall safety profile with manageable side effects resulting from LSD1 inhibition using bomedemstat in preclinical models. Altogether, our results support clinical testing of bomedemstat in the setting of mCRPC.

Two monogenic disorders masquerading as one: severe congenital neutropenia with monocytosis and non-syndromic sensorineural hearing loss.

BACKGROUND: We report a large family with four successive generations, presenting with a complex phenotype of severe congenital neutropenia (SCN), partially penetrant monocytosis, and hearing loss of varying severity. METHODS: We performed whole exome sequencing to identify the causative variants. Sanger sequencing was used to perform segregation analyses on remaining family members. RESULTS: We identified and classified a pathogenic GFI1 variant and a likely pathogenic variant in MYO6 which together explain the complex phenotypes seen in this family. CONCLUSIONS: We present a case illustrating the benefits of a broad screening approach that allows identification of oligogenic determinants of complex human phenotypes which may have been missed if the screening was limited to a targeted gene panel with the assumption of a syndromic disorder. This is important for correct genetic diagnosis of families and disentangling the range and severity of phenotypes associated with high impact variants.

LSD1 inhibition exerts its antileukemic effect by recommissioning PU.1- and C/EBPα-dependent enhancers in AML.

Epigenetic regulators are recurrently mutated and aberrantly expressed in acute myeloid leukemia (AML). Targeted therapies designed to inhibit these chromatin-modifying enzymes, such as the histone demethylase lysine-specific demethylase 1 (LSD1) and the histone methyltransferase DOT1L, have been developed as novel treatment modalities for these often refractory diseases. A common feature of many of these targeted agents is their ability to induce myeloid differentiation, suggesting that multiple paths toward a myeloid gene expression program can be engaged to relieve the differentiation blockade that is uniformly seen in AML. We performed a comparative assessment of chromatin dynamics during the treatment of mixed lineage leukemia (MLL)-AF9-driven murine leukemias and MLL-rearranged patient-derived xenografts using 2 distinct but effective differentiation-inducing targeted epigenetic therapies, the LSD1 inhibitor GSK-LSD1 and the DOT1L inhibitor EPZ4777. Intriguingly, GSK-LSD1 treatment caused global gains in chromatin accessibility, whereas treatment with EPZ4777 caused global losses in accessibility. We captured PU.1 and C/EBPα motif signatures at LSD1 inhibitor-induced dynamic sites and chromatin immunoprecipitation coupled with high-throughput sequencing revealed co-occupancy of these myeloid transcription factors at these sites. Functionally, we confirmed that diminished expression of PU.1 or genetic deletion of C/EBPα in MLL-AF9 cells generates resistance of these leukemias to LSD1 inhibition. These findings reveal that pharmacologic inhibition of LSD1 represents a unique path to overcome the differentiation block in AML for therapeutic benefit.

A public resource facilitating clinical use of genomes.

Rapid advances in DNA sequencing promise to enable new diagnostics and individualized therapies. Achieving personalized medicine, however, will require extensive research on highly reidentifiable, integrated datasets of genomic and health information. To assist with this, participants in the Personal Genome Project choose to forgo privacy via our institutional review board- approved "open consent" process. The contribution of public data and samples facilitates both scientific discovery and standardization of methods. We present our findings after enrollment of more than 1,800 participants, including whole-genome sequencing of 10 pilot participant genomes (the PGP-10). We introduce the Genome-Environment-Trait Evidence (GET-Evidence) system. This tool automatically processes genomes and prioritizes both published and novel variants for interpretation. In the process of reviewing the presumed healthy PGP-10 genomes, we find numerous literature references implying serious disease. Although it is sometimes impossible to rule out a late-onset effect, stringent evidence requirements can address the high rate of incidental findings. To that end we develop a peer production system for recording and organizing variant evaluations according to standard evidence guidelines, creating a public forum for reaching consensus on interpretation of clinically relevant variants. Genome analysis becomes a two-step process: using a prioritized list to record variant evaluations, then automatically sorting reviewed variants using these annotations. Genome data, health and trait information, participant samples, and variant interpretations are all shared in the public domain-we invite others to review our results using our participant samples and contribute to our interpretations. We offer our public resource and methods to further personalized medical research.

Cardiac R2* values are independent of the image analysis approach employed.

PURPOSE: To determine whether systematic differences were present between myocardial R2* values obtained with two different decay models: truncation and exponential + constant (Exp-C). METHODS: Single-center cohorts were used to compare black and bright blood sequences separately, and a multicenter cohort of mixed bright and black blood studies was used to assess the generalizability. Truncated exponential estimates were calculated with CMRtools, which uses a single region of interest (ROI) method. Exp-C estimates were calculated using a pixelwise approach. RESULTS: No differences could be distinguished based upon whether a white or black blood sequence was examined. The two fitting algorithms yielded similar R2* values, with R-squared values exceeding 0.997 and a coefficient of variation of 3% to 4%. Results using the pixelwise method yielded a small systematic bias (∼3%) that became apparent in patients with severe iron deposition. This disparity disappeared when Exp-C fitting was used on a single ROI, suggesting that the use of pixelwise mapping was responsible for the bias. In the multicenter cohort, the strong agreement between the two fitting approaches was reconfirmed. CONCLUSION: Cardiac R2* values are independent of the signal model used for its calculation over clinically relevant ranges. Clinicians can compare results among centers using these disparate approaches with confidence.

A phase 2 study of the safety, tolerability, and pharmacodynamics of FBS0701, a novel oral iron chelator, in transfusional iron overload.

This was a 24-week, multicenter phase-2 study designed to assess safety, tolerability, and pharmacodynamics of FBS0701, a novel oral chelator, in adults with transfusional iron overload. Fifty-one patients, stratified by transfusional iron intake, were randomized to FBS0701 at either 14.5 or 29 mg/kg/d (16 and 32 mg/kg/d salt form). FBS0701 was generally well tolerated at both doses. Forty-nine patients (96%) completed the study. There were no drug-related serious adverse events. No adverse events (AEs) showed dose-dependency in frequency or severity. Treatment-related nausea, vomiting, abdominal pain, and diarrhea were each noted in < 5% of patients. Mean serum creatinine did not change significantly from Baseline or between dose groups. Transaminases wer increased in 8 (16%), three of whom acquired HCV on-study from a single blood bank while five had an abnormal baseline ALT. The 24 week mean change in liver iron concentration (ΔLIC) at 14.5 mg/kg/d was +3.1 mg/g (dw); 29% achieved a decrease in LIC. Mean ΔLIC at 29 mg/kg/d was -0.3 mg/g (dw); 44% achieved a decrease in LIC (P < .03 for ΔLIC between doses). The safety and tolerability profile at therapeutic doses compare favorably to other oral chelators.

R2 and R2* are equally effective in evaluating chronic response to iron chelation.

MRI relaxometry (R2, R2*) has generally replaced liver biopsy for estimation of liver iron stores in response to iron chelation, but there have been no longitudinal studies comparing R2 and R2* techniques. We use R2 and R2* liver iron concentration (LIC) estimates, transfusional iron burdens, and drug compliance data to calculate iron chelation efficiency (ICE) in patients undergoing a Phase II trial of SPD602. Fifty-one patients underwent a baseline examination, 39 patients completed 1 year, and 26 patients completed 2 years. Baseline LICR2 and LICR2* estimates were unbiased, but had limits of agreement exceeding 50%, suggesting that these techniques cannot be interchanged with one another in the same patient. However, ICE estimates across the two techniques compared more favorably, with r(2) values reaching 0.89 at 2 years. 95 confidence intervals for efficiency estimates were 0.0 ± 4.1%. These data indicate that clinical trial and clinical effectiveness data calculated using LICR2 and LICR2* estimates can be compared to one another, even though LIC estimates may be disparate on cross-sectional analysis. While the choice of MRI assessment technique for clinical trials and for clinical management depends on many logistical considerations, one can have confidence comparing conclusions on clinical effectiveness.

A mutation in TGFB3 associated with a syndrome of low muscle mass, growth retardation, distal arthrogryposis and clinical features overlapping with Marfan and Loeys-Dietz syndrome.

The transforming growth factor ß (TGF-ß) family of growth factors are key regulators of mammalian development and their dysregulation is implicated in human disease, notably, heritable vasculopathies including Marfan (MFS, OMIM #154700) and Loeys-Dietz syndromes (LDS, OMIM #609192). We described a syndrome presenting at birth with distal arthrogryposis, hypotonia, bifid uvula, a failure of normal post-natal muscle development but no evidence of vascular disease; some of these features overlap with MFS and LDS. A de novo mutation in TGFB3 was identified by exome sequencing. Several lines of evidence indicate the mutation is hypomorphic suggesting that decreased TGF-ß signaling from a loss of TGFB3 activity is likely responsible for the clinical phenotype. This is the first example of a mutation in the coding portion of TGFB3 implicated in a clinical syndrome suggesting TGFB3 is essential for both human palatogenesis and normal muscle growth.

Bomedemstat as an investigative treatment for myeloproliferative neoplasms.

INTRODUCTION: Myeloproliferative neoplasm (MPN) is a heterogeneous group of hematopoietic stem cell disorders characterized by clonal proliferation of one of more of the hematopoietic stem cell lineages. Clinical manifestations result from uncontrolled myeloproliferation, extramedullary hematopoiesis with splenomegaly and excessive inflammatory cytokine production. Currently available therapy improves hematologic parameters and symptoms but does not adequately address the underlying neoplastic biology. Bomedemstat has thus far demonstrated clinical efficacy and tolerability in the treatment of MPNs with recent evidence of impacting the malignant stem cell population. AREAS COVERED: This review summarizes the mechanisms of action, pharmacokinetics and pharmacodynamics, safety and efficacy of bomedemstat in MPN with specific emphasis on essential thrombocythemia (ET) and myelofibrosis (MF). EXPERT OPINION: In patients with MPNs, bomedemstat appears effective and well tolerated. The signs and symptoms of these diseases are managed as a reduction in the frequency of mutant cells was demonstrated in patients with ET and MF. Ongoing and planned studies of bomedemstat in MPN will establish the position of bomedemstat in MPNs and may help to redefine treatment endpoints of MPNs in the future.

Chemical modulation of Schistosoma mansoni lysine specific demethylase 1 (SmLSD1) induces wide-scale biological and epigenomic changes.

Background: Schistosoma mansoni, a parasitic worm species responsible for the neglected tropical disease schistosomiasis, undergoes strict developmental regulation of gene expression that is carefully controlled by both genetic and epigenetic processes. As inhibition of S. mansoni epigenetic machinery components impairs key transitions throughout the parasite's digenetic lifecycle, a greater understanding of how epi-drugs affect molecular processes in schistosomes could lead to the development of new anthelmintics. Methods:   In vitro whole organism assays were used to assess the anti-schistosomal activity of 39 Homo sapiens Lysine Specific Demethylase 1 (HsLSD1) inhibitors on different parasite life cycle stages. Moreover, tissue-specific stains and genomic analysis shed light on the effect of these small molecules on the parasite biology. Results: Amongst this collection of small molecules, compound 33 was the most potent in reducing ex vivo viabilities of schistosomula, juveniles, miracidia and adults. At its sub-lethal concentration to adults (3.13 µM), compound 33 also significantly impacted oviposition, ovarian as well as vitellarian architecture and gonadal/neoblast stem cell proliferation. ATAC-seq analysis of adults demonstrated that compound 33 significantly affected chromatin structure (intragenic regions > intergenic regions), especially in genes differentially expressed in cell populations (e.g., germinal stem cells, hes2 + stem cell progeny, S1 cells and late female germinal cells) associated with these ex vivo phenotypes. KEGG analyses further highlighted that chromatin structure of genes associated with sugar metabolism as well as TGF-beta and Wnt signalling were also significantly perturbed by compound 33 treatment. Conclusions: This work confirms the importance of histone methylation in S. mansoni lifecycle transitions, suggesting that evaluation of LSD1 - targeting epi-drugs may facilitate the search for next-generation anti-schistosomal drugs. The ability of compound 33 to modulate chromatin structure as well as inhibit parasite survival, oviposition and stem cell proliferation warrants further investigations of this compound and its epigenetic target SmLSD1.

Somatic mutational landscape of hereditary hematopoietic malignancies caused by germline variants in RUNX1, GATA2, and DDX41.

Individuals with germ line variants associated with hereditary hematopoietic malignancies (HHMs) have a highly variable risk for leukemogenesis. Gaps in our understanding of premalignant states in HHMs have hampered efforts to design effective clinical surveillance programs, provide personalized preemptive treatments, and inform appropriate counseling for patients. We used the largest known comparative international cohort of germline RUNX1, GATA2, or DDX41 variant carriers without and with hematopoietic malignancies (HMs) to identify patterns of genetic drivers that are unique to each HHM syndrome before and after leukemogenesis. These patterns included striking heterogeneity in rates of early-onset clonal hematopoiesis (CH), with a high prevalence of CH in RUNX1 and GATA2 variant carriers who did not have malignancies (carriers-without HM). We observed a paucity of CH in DDX41 carriers-without HM. In RUNX1 carriers-without HM with CH, we detected variants in TET2, PHF6, and, most frequently, BCOR. These genes were recurrently mutated in RUNX1-driven malignancies, suggesting CH is a direct precursor to malignancy in RUNX1-driven HHMs. Leukemogenesis in RUNX1 and DDX41 carriers was often driven by second hits in RUNX1 and DDX41, respectively. This study may inform the development of HHM-specific clinical trials and gene-specific approaches to clinical monitoring. For example, trials investigating the potential benefits of monitoring DDX41 carriers-without HM for low-frequency second hits in DDX41 may now be beneficial. Similarly, trials monitoring carriers-without HM with RUNX1 germ line variants for the acquisition of somatic variants in BCOR, PHF6, and TET2 and second hits in RUNX1 are warranted.

Inhibition of LSD1 with Bomedemstat Sensitizes Small Cell Lung Cancer to Immune Checkpoint Blockade and T-Cell Killing.

PURPOSE: The addition of immune checkpoint blockade (ICB) to platinum/etoposide chemotherapy changed the standard of care for small cell lung cancer (SCLC) treatment. However, ICB addition only modestly improved clinical outcomes, likely reflecting the high prevalence of an immunologically "cold" tumor microenvironment in SCLC, despite high mutational burden. Nevertheless, some patients clearly benefit from ICB and recent reports have associated clinical responses to ICB in SCLC with (i) decreased neuroendocrine characteristics and (ii) activation of NOTCH signaling. We previously showed that inhibition of the lysine-specific demethylase 1a (LSD1) demethylase activates NOTCH and suppresses neuroendocrine features of SCLC, leading us to investigate whether LSD1 inhibition would enhance the response to PD-1 inhibition in SCLC. EXPERIMENTAL DESIGN: We employed a syngeneic immunocompetent model of SCLC, derived from a genetically engineered mouse model harboring Rb1/Trp53 inactivation, to investigate combining the LSD1 inhibitor bomedemstat with anti-PD-1 therapy. In vivo experiments were complemented by cell-based studies in murine and human models. RESULTS: Bomedemstat potentiated responses to PD-1 inhibition in a syngeneic model of SCLC, resulting in increased CD8+ T-cell infiltration and strong tumor growth inhibition. Bomedemstat increased MHC class I expression in mouse SCLC tumor cells in vivo and augmented MHC-I induction by IFNγ and increased killing by tumor-specific T cells in cell culture. CONCLUSIONS: LSD1 inhibition increased MHC-I expression and enhanced responses to PD-1 inhibition in vivo, supporting a new clinical trial to combine bomedemstat with standard-of-care PD-1 axis inhibition in SCLC.

A phase 1 dose-escalation study: safety, tolerability, and pharmacokinetics of FBS0701, a novel oral iron chelator for the treatment of transfusional iron overload.

BACKGROUND: There is still a clinical need for a well-tolerated and safe iron chelator for the treatment of transfusional iron overload. We describe the pharmacokinetic properties and safety data after 7 days of dosing of FBS0701, a novel oral, once-daily iron chelator. DESIGN AND METHODS: This phase 1b dose-escalation study to assess the safety, tolerability, pharmacokinetics and pharmacodynamics of FBS0701, a novel oral iron chelator for the treatment of transfusional iron overload, was conducted in 16 adult patients with iron overloaded consequent to transfusions. FBS0701 was given daily for 7 days at doses up to 32 mg/kg and was well tolerated at all dose levels. RESULTS: Pharmacokinetics showed dose-proportionality. The maxium plasma concentration (C(max)) was reached within 60-90 minutes of dosing and the drug was rapidly distributed at the predicted therapeutic doses. The plasma elimination half-life (t(1/2)) was approximately 19 hours. There were no serious adverse events associated with the drug. Conclusions On the basis of these safety and pharmacokinetic data, FBS0701 warrants further clinical evaluation in patients with transfusional iron overload. (Clinicaltrials.gov identifier: NCT01186419).

Dietary iron restriction or iron chelation protects from diabetes and loss of beta-cell function in the obese (ob/ob lep-/-) mouse.

Iron overload can cause insulin deficiency, but in some cases this may be insufficient to result in diabetes. We hypothesized that the protective effects of decreased iron would be more significant with increased beta-cell demand and stress. Therefore, we treated the ob/ob mouse model of type 2 diabetes with an iron-restricted diet (35 mg/kg iron) or with an oral iron chelator. Control mice were fed normal chow containing 500 mg/kg iron. Neither treatment resulted in iron deficiency or anemia. The low-iron diet significantly ameliorated diabetes in the mice. The effect was long lasting and reversible. Ob/ob mice on the low-iron diet exhibited significant increases in insulin sensitivity and beta-cell function, consistent with the phenotype in mouse models of hereditary iron overload. The effects were not accounted for by changes in weight or feeding behavior. Treatment with iron chelation had a more dramatic effect, allowing the ob/ob mice to maintain normal glucose tolerance for at least 10.5 wk despite no effect on weight. Although dietary iron restriction preserved beta-cell function in ob/ob mice fed a high-fat diet, the effects on overall glucose levels were less apparent due to a loss of the beneficial effects of iron on insulin sensitivity. Beneficial effects of iron restriction were minimal in wild-type mice on normal chow but were apparent in mice on high-fat diets. We conclude that, even at "normal" levels, iron exerts detrimental effects on beta-cell function that are reversible with dietary restriction or pharmacotherapy.

Leukemia Cell of Origin Influences Apoptotic Priming and Sensitivity to LSD1 Inhibition.

The cell of origin of oncogenic transformation is a determinant of therapeutic sensitivity, but the mechanisms governing cell-of-origin-driven differences in therapeutic response have not been delineated. Leukemias initiating in hematopoietic stem cells (HSC) are less sensitive to chemotherapy and highly express the transcription factor MECOM (EVI1) compared with leukemias derived from myeloid progenitors. Here, we compared leukemias initiated in either HSCs or myeloid progenitors to reveal a novel function for EVI1 in modulating p53 protein abundance and activity. HSC-derived leukemias exhibit decreased apoptotic priming, attenuated p53 transcriptional output, and resistance to lysine-specific demethylase 1 (LSD1) inhibitors in addition to classical genotoxic stresses. p53 loss of function in Evi1 lo progenitor-derived leukemias induces resistance to LSD1 inhibition, and EVI1hi leukemias are sensitized to LSD1 inhibition by venetoclax. Our findings demonstrate a role for EVI1 in p53 wild-type cancers in reducing p53 function and provide a strategy to circumvent drug resistance in chemoresistant EVI1 hi acute myeloid leukemia. SIGNIFICANCE: We demonstrate that the cell of origin of leukemia initiation influences p53 activity and dictates therapeutic sensitivity to pharmacologic LSD1 inhibitors via the transcription factor EVI1. We show that drug resistance could be overcome in HSC-derived leukemias by combining LSD1 inhibition with venetoclax.See related commentary by Gu et al., p. 1445.This article is highlighted in the In This Issue feature, p. 1426.

RUNX1-mutated families show phenotype heterogeneity and a somatic mutation profile unique to germline predisposed AML.

First reported in 1999, germline runt-related transcription factor 1 (RUNX1) mutations are a well-established cause of familial platelet disorder with predisposition to myeloid malignancy (FPD-MM). We present the clinical phenotypes and genetic mutations detected in 10 novel RUNX1-mutated FPD-MM families. Genomic analyses on these families detected 2 partial gene deletions, 3 novel mutations, and 5 recurrent mutations as the germline RUNX1 alterations leading to FPD-MM. Combining genomic data from the families reported herein with aggregated published data sets resulted in 130 germline RUNX1 families, which allowed us to investigate whether specific germline mutation characteristics (type, location) could explain the large phenotypic heterogeneity between patients with familial platelet disorder and different HMs. Comparing the somatic mutational signatures between the available familial (n = 35) and published sporadic (n = 137) RUNX1-mutated AML patients showed enrichment for somatic mutations affecting the second RUNX1 allele and GATA2. Conversely, we observed a decreased number of somatic mutations affecting NRAS, SRSF2, and DNMT3A and the collective genes associated with CHIP and epigenetic regulation. This is the largest aggregation and analysis of germline RUNX1 mutations performed to date, providing a unique opportunity to examine the factors underlying phenotypic differences and disease progression from FPD to MM.