NSD2 drives t(4;14) myeloma cell dependence on adenylate kinase 2 by diverting one-carbon metabolism to the epigenome.

ABSTRACT: Chromosomal translocation (4;14), an adverse prognostic factor in multiple myeloma (MM), drives overexpression of the histone methyltransferase nuclear receptor binding SET domain protein 2 (NSD2). A genome-wide CRISPR screen in MM cells identified adenylate kinase 2 (AK2), an enzyme critical for high-energy phosphate transfer from the mitochondria, as an NSD2-driven vulnerability. AK2 suppression in t(4;14) MM cells decreased nicotinamide adenine dinucleotide phosphate (NADP[H]) critical for conversion of ribonucleotides to deoxyribonucleosides, leading to replication stress, DNA damage, and apoptosis. Driving a large genome-wide increase in chromatin methylation, NSD2 overexpression depletes S-adenosylmethionine, compromising the synthesis of creatine from its precursor, guanidinoacetate. Creatine supplementation restored NADP(H) levels, reduced DNA damage, and rescued AK2-deficient t(4;14) MM cells. As the creatine phosphate shuttle constitutes an alternative means for mitochondrial high-energy phosphate transport, these results indicate that NSD2-driven creatine depletion underlies the hypersensitivity of t(4;14) MM cells to AK2 loss. Furthermore, AK2 depletion in t(4;14) cells impaired protein folding in the endoplasmic reticulum, consistent with impaired use of mitochondrial adenosine triphosphate (ATP). Accordingly, AK2 suppression increased the sensitivity of MM cells to proteasome inhibition. These findings delineate a novel mechanism in which aberrant transfer of carbon to the epigenome creates a metabolic vulnerability, with direct therapeutic implications for t(4;14) MM.

BCL3 rearrangements in B-cell lymphoid neoplasms occur in two breakpoint clusters associated with different diseases.

The t(14;19)(q32;q13) often juxtaposes BCL3 with immunoglobulin heavy chain (IGH) resulting in overexpression of the gene. In contrast to other oncogenic translocations, BCL3 rearrangement (BCL3-R) has been associated with a broad spectrum of lymphoid neoplasms. Here we report an integrative whole-genome sequence, transcriptomic, and DNA methylation analysis of 13 lymphoid neoplasms with BCL3-R. The resolution of the breakpoints at single base-pair revealed that they occur in two clusters at 5' (n=9) and 3' (n=4) regions of BCL3 associated with two different biological and clinical entities. Both breakpoints were mediated by aberrant class switch recombination of the IGH locus. However, the 5' breakpoints (upstream) juxtaposed BCL3 next to an IGH enhancer leading to overexpression of the gene whereas the 3' breakpoints (downstream) positioned BCL3 outside the influence of the IGH and were not associated with its expression. Upstream BCL3-R tumors had unmutated IGHV, trisomy 12, and mutated genes frequently seen in chronic lymphocytic leukemia (CLL) but had an atypical CLL morphology, immunophenotype, DNA methylome, and expression profile that differ from conventional CLL. In contrast, downstream BCL3-R neoplasms were atypical splenic or nodal marginal zone lymphomas (MZL) with mutated IGHV, complex karyotypes and mutated genes typical of MZL. Two of the latter four tumors transformed to a large B-cell lymphoma. We designed a novel fluorescence in situ hybridization assay that recognizes the two different breakpoints and validated these findings in 17 independent tumors. Overall, upstream or downstream breakpoints of BCL3-R are mainly associated with two subtypes of lymphoid neoplasms with different (epi)genomic, expression, and clinicopathological features resembling atypical CLL and MZL, respectively.

Epigenetic dysregulation of eukaryotic initiation factor 3 subunit E (eIF3E) by lysine methyltransferase REIIBP confers a pro-inflammatory phenotype in t(4;14) myeloma.

REIIBP is a lysine methyltransferase aberrantly expressed through alternative promoter usage of NSD2 locus in t(4;14)-translocated multiple myeloma (MM). Clinically, t(4;14) translocation is an adverse prognostic factor found in approximately 15% of MM patients. The contribution of REIIBP relative to other NSD2 isoforms as a dependency gene in t(4;14)-translocated MM remains to be evaluated. Here, we demonstrated that despite homology with NSD2, REIIBP displayed distinct substrate specificity by preferentially catalyzing H3K4me3 and H3K27me3, with little activity on H3K36me2. Furthermore, REIIBP was regulated through microRNA by EZH2 in a Dicer-dependent manner, exemplifying a role of REIIBP in SET-mediated H3K27me3. Chromatin immunoprecipitation sequencing revealed chromatin remodeling characterized by changes in genome-wide and loci-specific occupancy of these opposing histone marks, allowing a bidirectional regulation of its target genes. Transcriptomics indicated that REIIBP induced a pro-inflammatory gene signature through upregulation of TLR7, which in turn led to B-cell receptor-independent activation of BTK and driving NFkB-mediated production of cytokines such as IL-6. Activation of this pathway is targetable using Ibrutinib and partially mitigated bortezomib resistance in a REIIBP xenograft model. Mechanistically, REIIBP upregulated TLR7 through eIF3E, and this relied on eIF3E RNA-binding function instead of its canonical protein synthesis activity, as demonstrated by direct binding to the 3'UTR of TLR7 mRNA. Altogether, we provided a rationale that co-existence of different NSD2 isoforms induced diversified oncogenic programs that should be considered in the strategies for t(4;14)-targeted therapy.

Adults with paternal UPD14 causing Kagami-Ogata syndrome: Case report and review of the literature.

Kagami-Ogata syndrome (KOS) is a clinically recognizable syndrome in the neonatal period. It is characterized by specific skeletal anomalies and facial dysmorphisms. It is typically caused by paternal uniparental disomy of chromosome 14, while epimutations and microdeletions are less commonly reported causes. In the pediatric setting, KOS is a well delineated syndrome. However, there is a dearth of literature describing the natural history of the condition in adults. Herein, we describe a 35-year-old man, the first adult with KOS reported due to paternal uniparental disomy 14, and review reports of KOS in other affected adults. This highlights the variability in neurocognitive phenotypes, the presence of connective tissue abnormalities, and the uncertainties around long-term cancer risk.

14q22.3 duplication including OTX2 in a girl with medulloblastoma: A case report with literature review.

Orthodenticle homeobox 2 (OTX2) is a known oncogenic driver of medulloblastoma. Germline duplication of 14q22.3 including OTX2 is a rare condition reported in patients with combined pituitary hormone deficiency, oculo-auriculo-vertebral spectrum, and hemifacial microsomia. There has been one previously published case of a patient carrying a 14q22.3 duplication that included OTX2 with hemifacial microsomia who also developed medulloblastoma. Here, we present a case of a 6-year-old girl with a history of delayed development who was diagnosed with medulloblastoma. Genetic evaluations revealed that she inherited a germline duplication of 14q22.3, which included OTX2. This genetic alteration was passed down from her mother, who also had a history of delayed development. Results from other genetic testing, including exome sequencing, fragile X syndrome, and mtDNA testing, were negative/normal. This is the second report of a 14q22.3 duplication that included OTX2 in a patient with medulloblastoma. Further studies are necessary to establish a clear association.

Continued Success of Venetoclax in t(11;14) Multiple Myeloma Despite Negative Trials.

The June Hot Topics focuses on the challenges venetoclax regimens have faced in multiple myeloma trials.

Childhood and Adolescent Relapsed/Refractory Aggressive B-Cell Lymphomas With t(8;14) and BCL2 Expression, Burkitt Lymphoma Versus Diffuse Large B-Cell Lymphoma: A Diagnostic Challenge.

We present 2 diagnostically challenging cases of pediatric/adolescent relapsed/refractory aggressive mature B-cell non-Hodgkin lymphoma (B-NHL) within the spectrum of Burkitt lymphoma and diffuse large B-cell lymphoma and illustrate the different therapeutic regimens that are employed for pediatric and adult cancer centers. Both cases displayed varying-sized lymphoma cells with occasional single prominent nucleoli and heterogeneous BCL2 expression. Cytogenetics revealed complex karyotypes with t(8:14)(q24.2;q32) and IGH::MYC rearrangement by FISH. Next generation sequencing revealed deleterious TP53 and MYC mutations. We concluded that both could be diagnosed as "DLBCL-NOS with MYC rearrangement" using the current pathologic classifications, 2022 International Consensus Classification (ICC) and World Health Organization Classifications of Haematolymphoid Tumors (WHO-HAEM5). This report illustrates diagnostic challenges and treatment dilemmas that may be encountered, particularly for adolescent and young adults (AYA).

Genetic Analysis of a Fetus with 14q11.2 Microdeletion in Ultrasound Abnormalities.

BACKGROUND: This study aimed to explore the genetic basis of a fetus with ultrasound indicating a thickening of the nuchal translucency (NT) and a choroid plexus cyst. METHODS: Fetal amniotic fluid and peripheral blood were collected for a G-banding karyotype analysis and single nucleotide polymorphism array (SNP-array) detection. RESULTS: The chromosome karyotypes of the fetus and its parents were normal. SNP-array showed the fetus had carried 277 kb microdeletion at 14q11.2, which was a new mutation. After the induced abortion, the fetus was diagnosed with macrocephaly. CONCLUSIONS: A prenatal diagnosis of a fetus with 14q11.2 microdeletion-induced intrauterine growth retardation was confirmed, which has provided guidance for the subsequent pregnancy.

A rare case of IgA lambda multiple myeloma in a 32-year-old woman with t(14;16) translocation associated with kidney injury and non-albumin proteinuria.

BACKGROUND: Multiple myeloma (MM) is a malignant disorder characterized by monoclonal differentiated plasma cells. While it is more commonly diagnosed in elderly individuals, it can also affect younger populations, though with a lower incidence. CASE PRESENTATION: Here, we present the case of a 32-year-old woman diagnosed with IgA lambda MM. She presented with fatigue, nausea, acute kidney injury (AKI) with a rapid increase in creatinine, and anemia. A kidney biopsy was done to rule out a rapidly progressive glomerular disease and a diagnosis was thus reached. A genetic workup revealed t(14;16) translocation and an extra copy of TP53. The patient received aggressive intravenous steroids and intravenous fluid resuscitation, resulting in an improvement in renal function. Treatment with daratumumab in combination with bortezomib, thalidomide, and dexamethasone was initiated and well tolerated. Despite the generally poor prognosis of IgA MM, our case emphasizes the importance of considering MM in young patients with unexplained kidney injury. CONCLUSION: Early recognition and prompt intervention are essential in managing MM patients, especially in those with high-risk cytogenetic abnormalities. This case serves as a reminder for clinicians to maintain a high index of suspicion for MM, even in younger populations, when presented with unexplained kidney injury.

Use of venetoclax in t(11;14) positive relapsed/refractory multiple myeloma: A systematic review.

BACKGROUND: The plasma cell malignancy, multiple myeloma (MM), remains incurable despite advanced treatment protocols. Overexpression of Bcl-2 (an anti-apoptotic protein), in MM harboring the translocation (11;14), contributes to resistance to prior therapy. Venetoclax, a selective oral inhibitor of BCL-2 is a novel agent that shows promise as a therapeutic agent. AIMS: The objective of this systematic review is to address how the use of venetoclax, alone or as a combination regimen, contributed to the treatment of patients with t(11:14) positive relapsed/refractory multiple myeloma (RRMM). DATA SOURCES: This systematic review was conducted in accordance to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and was done on 5th June 2022. A literature search was conducted on PubMed and Scopus, 145 articles were screened and 10 studies were included. Risk of bias assessment was performed using the Methodological Index for Non-Randomized Studies (MINORS) criteria. DATA SUMMARY: Across the studies reviewed, a total of 311 patients were identified with t(11;14) positive RRMM. The overall response rate achieved ranged between 33% and 95.5%. Furthermore, the use of venetoclax has exhibited a favorable adverse effect profile. Side effects included hematological side effects, nausea, vomiting, and diarrhea. CONCLUSION: Venetoclax demonstrates promising results. When given with drugs like dexamethasone, daratumumab and carfilzomib, a synergistic effect is seen in treating translocation (11:14) positive relapsed/refractory MM. The use of venetoclax in clinical practice can potentially improve outcomes and quality of life in RRMM patients, and future research should continue to explore this promising treatment option.

Imaging flow cytometry-based multiplex FISH for three IGH translocations in multiple myeloma.

Three types of chromosomal translocations, t(4;14)(p16;q32), t(14;16)(q32;q23), and t(11;14)(q13;q32), are associated with prognosis and the decision making of therapeutic strategy for multiple myeloma (MM). In this study, we developed a new diagnostic modality of the multiplex FISH in immunophenotyped cells in suspension (Immunophenotyped-Suspension-Multiplex (ISM)-FISH). For the ISM-FISH, we first subject cells in suspension to the immunostaining by anti-CD138 antibody and, then, to the hybridization with four different FISH probes for genes of IGH, FGFR3, MAF, and CCND1 tagged by different fluorescence in suspension. Then, cells are analyzed by the imaging flow cytometry MI-1000 combined with the FISH spot counting tool. By this system of the ISM-FISH, we can simultaneously examine the three chromosomal translocations, i.e, t(4;14), t(14;16), and t(11;14), in CD138-positive tumor cells in more than 2.5 × 104 nucleated cells with the sensitivity at least up to 1%, possibly up to 0.1%. The experiments on bone marrow nucleated cells (BMNCs) from 70 patients with MM or monoclonal gammopathy of undetermined significance demonstrated the promising qualitative diagnostic ability in detecting t(11;14), t(4;14), and t(14;16) of our ISM-FISH, which was more sensitive compared with standard double-color (DC) FISH examining 200 interphase cells with its best sensitivity up to 1.0%. Moreover, the ISM-FISH showed a positive concordance of 96.6% and negative concordance of 98.8% with standard DC-FISH examining 1000 interphase cells. In conclusion, the ISM-FISH is a rapid and reliable diagnostic tool for the simultaneous examination of three critically important IGH translocations, which may promote risk-adapted individualized therapy in MM.

14q32 rearrangements deregulating BCL11B mark a distinct subgroup of T-lymphoid and myeloid immature acute leukemia.

Acute leukemias (ALs) of ambiguous lineage are a heterogeneous group of high-risk leukemias characterized by coexpression of myeloid and lymphoid markers. In this study, we identified a distinct subgroup of immature acute leukemias characterized by a broadly variable phenotype, covering acute myeloid leukemia (AML, M0 or M1), T/myeloid mixed-phenotype acute leukemia (T/M MPAL), and early T-cell precursor acute lymphoblastic leukemia (ETP-ALL). Rearrangements at 14q32/BCL11B are the cytogenetic hallmark of this entity. In our screening of 915 hematological malignancies, there were 202 AML and 333 T-cell acute lymphoblastic leukemias (T-ALL: 58, ETP; 178, non-ETP; 8, T/M MPAL; 89, not otherwise specified). We identified 20 cases of immature leukemias (4% of AML and 3.6% of T-ALL), harboring 4 types of 14q32/BCL11B translocations: t(2,14)(q22.3;q32) (n = 7), t(6;14)(q25.3;q32) (n = 9), t(7;14)(q21.2;q32) (n = 2), and t(8;14)(q24.2;q32) (n = 2). The t(2;14) produced a ZEB2-BCL11B fusion transcript, whereas the other 3 rearrangements displaced transcriptionally active enhancer sequences close to BCL11B without producing fusion genes. All translocations resulted in the activation of BCL11B, a regulator of T-cell differentiation associated with transcriptional corepressor complexes in mammalian cells. The expression of BCL11B behaved as a disease biomarker that was present at diagnosis, but not in remission. Deregulation of BCL11B co-occurred with variants at FLT3 and at epigenetic modulators, most frequently the DNMT3A, TET2, and/or WT1 genes. Transcriptome analysis identified a specific expression signature, with significant downregulation of BCL11B targets, and clearly separating BCL11B AL from AML, T-ALL, and ETP-ALL. Remarkably, an ex vivo drug-sensitivity profile identified a panel of compounds with effective antileukemic activity.

Venetoclax sensitivity in multiple myeloma is associated with B-cell gene expression.

Venetoclax is a highly potent, selective BCL2 inhibitor capable of inducing apoptosis in cells dependent on BCL2 for survival. Most myeloma is MCL1-dependent; however, a subset of myeloma enriched for translocation t(11;14) is codependent on BCL2 and thus sensitive to venetoclax. The biology underlying this heterogeneity remains poorly understood. We show that knockdown of cyclin D1 does not induce resistance to venetoclax, arguing against a direct role for cyclin D1 in venetoclax sensitivity. To identify other factors contributing to venetoclax response, we studied a panel of 31 myeloma cell lines and 25 patient samples tested for venetoclax sensitivity. In cell lines, we corroborated our previous observation that BIM binding to BCL2 correlates with venetoclax response and further showed that knockout of BIM results in decreased venetoclax sensitivity. RNA-sequencing analysis identified expression of B-cell genes as enriched in venetoclax-sensitive myeloma, although no single gene consistently delineated sensitive and resistant cells. However, a panel of cell surface makers correlated well with ex vivo prediction of venetoclax response in 21 patient samples and may serve as a biomarker independent of t(11;14). Assay for transposase-accessible chromatin sequencing of myeloma cell lines also identified an epigenetic program in venetoclax-sensitive cells that was more similar to B cells than that of venetoclax-resistant cells, as well as enrichment for basic leucine zipper domain-binding motifs such as BATF. Together, these data indicate that remnants of B-cell biology are associated with BCL2 dependency and point to novel biomarkers of venetoclax-sensitive myeloma independent of t(11;14).

Maternally inherited deletion encompassing the RTL1as and MEG8 genes of the human 14q32 imprinted region in a patient with a mild Kagami-Ogata syndrome phenotype.

Kagami-Ogata syndrome and Temple syndrome are imprinting disorders caused by the abnormal expression of genes in an imprinted cluster on chromosome 14q32. Here, we report a female with mild features of the Kagami-Ogata syndrome phenotype with polyhydramnios, neonatal hypotonia, feeding difficulties, abnormal foot morphology, patent foramen ovale, distal arthrogryposis, normal facial profile, and a bell-shaped thorax without coat hanger ribs. The single nucleotide polymorphism array revealed the interstitial deletion of chromosome 14q32.2-q32.31 (117 kb in size), involving the RTL1as and MEG8 genes, and other small nucleolar RNAs and microRNAs. The differentially methylated regions (DMRs) appeared unaltered. The RTL1as gene deletion and the normal methylation pattern of the MEG3 gene loci were confirmed by methylation-specific multiplex ligation-dependent probe amplification. Deletions of the 14q32 region without involving DMRs, and encompassing only the RTL1as and MEG8 genes, are poorly described in the literature. The mother's chromosomal microarray also confirmed the identical 14q32.2 deletion, although she presented a normal phenotype. The maternally inherited 14q32 deletion was responsible for Kagami-Ogata syndrome in our patient. It was not sufficient, however, to produce Temple syndrome or any other pathogenic phenotype in the patient's mother.

Risk prediction for metastasis of clear cell renal cell carcinoma using digital multiplex ligation-dependent probe amplification.

Precise quantification of copy-number alterations (CNAs) in a tumor genome is difficult. We have applied a comprehensive copy-number analysis method, digital multiplex ligation-dependent probe amplification (digitalMLPA), for targeted gene copy-number analysis in clear cell renal cell carcinoma (ccRCC). Copy-number status of all chromosomal arms and 11 genes was determined in 60 ccRCC samples. Chromosome 3p loss and 5q gain, known as early changes in ccRCC development, as well as losses at 9p and 14q were detected in 56/60 (93.3%), 31/60 (51.7%), 11/60 (18.3%), and 33/60 (55%), respectively. Through gene expression analysis, a significant positive correlation was detected in terms of 14q loss determined using digitalMLPA and downregulation of mRNA expression ratios with HIF1A and L2HGDH (P = .0253 and .0117, respectively). Patients with early metastasis (<1 y) (n = 18) showed CNAs in 6 arms (in median), whereas metastasis-free patients (n = 34) showed those in significantly less arms (3 arms in median) (P = .0289). In particular, biallelic deletion of CDKN2A/2B was associated with multiple CNAs (≥7 arms) in 3 tumors. Together with sequence-level mutations in genes VHL, PBRM1, SETD2, and BAP1, we performed multiple correspondence analysis, which identified the association of 9p loss and 4q loss with early metastasis (both P < .05). This analysis indicated the association of 4p loss and 1p loss with poor survival (both, P < .05). These findings suggest that CNAs have essential roles in aggressiveness of ccRCC. We showed that our approach of measuring CNA through digitalMLPA will facilitate the selection of patients who may develop metastasis.

Temple syndrome and Kagami-Ogata syndrome: clinical presentations, genotypes, models and mechanisms.

Temple syndrome (TS) and Kagami-Ogata syndrome (KOS) are imprinting disorders caused by absence or overexpression of genes within a single imprinted cluster on human chromosome 14q32. TS most frequently arises from maternal UPD14 or epimutations/deletions on the paternal chromosome, whereas KOS most frequently arises from paternal UPD14 or epimutations/deletions on the maternal chromosome. In this review, we describe the clinical symptoms and genetic/epigenetic features of this imprinted region. The locus encompasses paternally expressed protein-coding genes (DLK1, RTL1 and DIO3) and maternally expressed lncRNAs (MEG3/GTL2, RTL1as and MEG8), as well as numerous miRNAs and snoRNAs. Control of expression is complex, with three differentially methylated regions regulating germline, placental and tissue-specific transcription. The strong conserved synteny between mouse chromosome 12aF1 and human chromosome 14q32 has enabled the use of mouse models to elucidate imprinting mechanisms and decipher the contribution of genes to the symptoms of TS and KOS. In this review, we describe relevant mouse models and highlight their value to better inform treatment options for long-term management of TS and KOS patients.

Hematological and Genetic Markers in the Rational Approach to Patients With HCV Sustained Virological Response With or Without Persisting Cryoglobulinemic Vasculitis.

BACKGROUND AND AIMS: Direct-acting antivirals (DAAs) usually lead to improvement/remission of cryoglobulinemic vasculitis (CV), although symptoms may persist/recur after a sustained virological response (SVR). We evaluated hematological and genetic markers in patients with HCV-SVR vasculitis with and without persisting/recurring symptoms to early predict the CV outcome. APPROACH AND RESULTS: Ninety-eight patients with HCV-CV were prospectively enrolled after a DAA-induced SVR: Group A: 52 with complete clinical response; Group B: 46 with symptom maintenance/recurrence. Monoclonal B-cell lymphocytosis, t(14;18) translocation, and abnormal free light chains κ/λ ratios were detected by flow cytometry or nested-PCR or nephelometry in 4% Group A versus 17% Group B (P = 0.04) patients, 17% Group A versus 40% Group B patients (P = 0.02), and 17% Group A versus 47% Group B (P = 0.003) patients, respectively. At least 1 out of 3 clonality markers was altered/positive in 29% of Group A versus 70% of Group B patients (P < 0.0001). When available, pretherapy samples were also tested for t(14;18) translocation (detected in 12/37 [32%] Group A and 21/38 [55%] Group B) and κ/λ ratios (abnormal in 5/35 [14%] Group A and 20/38 [53%] Group B) (P = 0.0006), whereas at least one clonality marker was detected/altered in 16/37 (43%) Group A and 30/38 (79%) Group B (P = 0.002). CV-associated single-nucleotide polymorphisms were tested by real-time PCR. Among them, notch4 rs2071286 T minor allele and TT genotype showed a higher frequency in Group B versus Group A (46% vs. 29%, P = 0.01, and 17% vs. 2%, P = 0.006, respectively). CONCLUSIONS: Hematological or genetic analyses could be used to foresee the CV clinical response after DAA therapy and could be valuable to assess a rational flowchart to manage CV during follow-up.

Increased complexity of t(11;14) rearrangements in plasma cell neoplasms compared with mantle cell lymphoma.

Plasma cell neoplasms (PCN) and mantle cell lymphoma (MCL) can both harbor t(11;14)(q13;q32) (CCND1/IGH), usually resulting in cyclin D1 overexpression. In some cases, particularly at low levels of disease, it can be morphologically challenging to distinguish between these entities in the bone marrow (BM) since PCN with t(11;14) are often CD20-positive with lymphoplasmacytic cytology, while MCL can rarely have plasmacytic differentiation. We compared the difference in CCND1/IGH by fluorescence in situ hybridization (FISH) in PCN and MCL to evaluate for possible differentiating characteristics. We identified 326 cases of MCL with t(11;14) and 279 cases of PCN with t(11;14) from either formalin-fixed, paraffin-embedded tissue or fresh BM specimens. The "typical," balanced CCND1/IGH FISH signal pattern was defined as three total CCND1 signals, three total IGH signals, and two total fusion signals. Any deviation from the "typical" pattern was defined as an "atypical" pattern, which was further stratified into "gain of fusion" vs "complex" patterns. There was a significantly higher proportion of cases that showed an atypical FISH pattern in PCN compared with MCL (53% vs 27%, P < .0001). There was also a significantly higher proportion of cases that showed a complex FISH pattern in PCN compared with MCL (47% vs 17%, P < .0001). We confirmed these findings using mate-pair sequencing of 25 PCN and MCL samples. PCN more often have a complex CCND1/IGH FISH pattern compared with MCL, suggesting possible differences in the genomic mechanisms underlying these rearrangements in plasma cells compared with B cells.

Multiple myeloma with t(11;14)-associated immature phenotype has lower CD38 expression and higher BCL2 dependence.

CD38 expression on myeloma cells is a critical factor affecting the early response to the anti-CD38 antibody daratumumab. However, factors affecting CD38 expression in untreated multiple myeloma are not fully elucidated. In this study, we found that CD38 expression was significantly lower in myeloma patients with the translocation t(11;14)-associated immature plasma cell phenotype, and particularly in those expressing B-cell-associated genes such as PAX5 and CD79A. CD138, a representative marker of plasmacytic differentiation, was also significantly lower in these patients, suggesting that CD38 expression may be associated with the differentiation and maturation stages of myeloma cells. Furthermore, the BCL2/BCL2L1 ratio, a response marker of the BCL2 inhibitor venetoclax, was significantly higher in patients with the immature phenotype expressing B-cell-associated genes. The BCL2/BCL2L1 ratio and CD38 expression were significantly negatively correlated. We also confirmed that patients with translocation t(11;14) expressing B-cell-associated genes were indeed less sensitive to daratumumab-mediated direct cytotoxicity but highly sensitive to venetoclax treatment in ex vivo assays. Moreover, all-trans-retinoic acid, which enhances CD38 expression and induces cell differentiation in myeloma cells, reduced B-cell marker expression and the BCL2/BCL2L1 ratio in myeloma cell lines, leading to reduced efficacy of venetoclax. Venetoclax specifically induces cell death in myeloma with t(11;14), although why patients with translocation t(11;14) show BCL2 dependence is unclear. These results suggest that BCL2 dependence, as well as CD38 expression, are deeply associated with the differentiation and maturation stages of myeloma cells. This study highlights the importance of examining t(11;14) and considering cell maturity in myeloma treatment strategies.

Kagami-Ogata syndrome in a patient with 46,XX,t(2;14)(q11.2;q32.2)mat disrupting MEG3.

Kagami-Ogata syndrome (KOS14) is a rare imprinting disorder characterized by a unique constellation of phenotypes including bell-shaped small thorax with coat-hanger appearance of the ribs. We encountered an African American female infant with KOS14 phenotype and 46,XX,t(2;14)(q11.2;q32.2)mat. After excluding upd(14)pat and an epimutation (hypermethylation) and a deletion affecting the maternally derived 14q32.2 imprinted region, we performed whole-genome sequencing, revealing that the translocation was generated between noncoding region at 2q11.2 and intron 6 of MEG3 at 14q32.2. Subsequent Sanger sequencing for the fusion points showed that the chromosomal fusion on the der(2) chromosome occurred between Chr2:102,193,994 (bp) and Chr14:101,314,628 (bp) in association with an insertion of 5-bp segment of unknown origin and that on the der(14) chromosome took place between Chr14:101,314,627 (bp) and Chr2:102,193,995 (bp) in association with an insertion of 1-bp segment of unknown origin (according to GRCh37/hg19). The results, together with the previous data in patients with KOS14, imply that the MEG3 disruption by 46,XX,t(2;14)(q11.2;q32.2)mat caused silencing of all MEGs including RTL1as and resultant excessive RTL1 expression, leading to the development of KOS14. To our knowledge, while Robertsonian translocations involving chromosome 14 have been reported in KOS14, this is the first case of KOS14 caused by a chromosomal translocation involving the 14q32.2 imprinted region.