High-grade B-cell lymphoma with 11q aberration in the HIV setting: a clinicopathological study of 10 cases and literature review.

High-grade B-cell lymphoma with 11q aberration (HGBL-11q) is a distinct lymphoma entity according to the 5th edition of the WHO classification of hematolymphoid tumors. It lacks MYC translocation but carries proximal gains and/or telomeric losses of chromosome 11q. This rare type of B-cell lymphoma is less frequently reported in people living with HIV (PLWH), and its exact frequency remains unclear. Our goal was to retrospectively analyze its frequency in a cohort of aggressive B-cell lymphomas in PLWH, including Burkitt lymphoma (BL, n = 35), diffuse large B-cell lymphoma (DLBCL, n = 48), high-grade B-cell lymphoma, not otherwise specified (HGBL-NOS, n = 13), which was diagnosed as AIDS-related lymphoma (ARL) at our institution. In total, 10/96 (10.4%) cases harbored the typical 11q aberration pattern, predominantly those that had been classified as BL (6/35, 17.1%), DLBCL (2/48, 4.2%), and HGBL, NOS (2/13, 15.4%). We also evaluated 7 cases of AIDS-related HGBL-11q (AR-HGBL-11q) reported in the literature. The median age of our cohort was 35 years, and all the patients were male. Most cases (70%) had a history of HIV infection for over 1 year, and all were involved in lymph nodes (100%), frequently involved extranodal sites (60%), and Ann Arbor stage III/IV. In histomorphology, the cases exhibited diverse cytological features, reminiscent of BL (6 cases), DLBCL (2 cases), and HGBL (2 cases). A comparison of the combined cohort of 17 AR-HGBL-11q cases with 11 ARL cases that lacked both MYC rearrangement and 11q aberration at our institution showed that HGBL-11q cases were characterized by strikingly coarse apoptotic debris (P < 0.001), background rich in eosinophils (P = 0.002), higher expression of the germinal centre marker LMO2 (P = 0.080), lower expression of MUM1 (P = 0.004), BCL2 (P = 0.007), and LEF1 (P = 0.080), and lower positivity for EBER in situ hybridisation (P = 0.027). Notably, one case in our series was EBV-positive, a finding not previously reported in the literature. Furthermore, comparing the prognosis between these two groups, AR-HGBL-11q showed a relatively favorable prognosis (P = 0.15), although the difference was not statistically significant. We analyzed this rare lymphoma entity in the HIV setting and highlighted the importance of integrating histomorphological and immunophenotypic features in its diagnosis and classification.

MicroRNA Profiling as a Predictive Indicator for Time to First Treatment in Chronic Lymphocytic Leukemia: Insights from the O-CLL1 Prospective Study.

A "watch and wait" strategy, delaying treatment until active disease manifests, is adopted for most CLL cases; however, prognostic models incorporating biomarkers have shown to be useful to predict treatment requirement. In our prospective O-CLL1 study including 224 patients, we investigated the predictive role of 513 microRNAs (miRNAs) on time to first treatment (TTFT). In the context of this study, six well-established variables (i.e., Rai stage, beta-2-microglobulin levels, IGVH mutational status, del11q, del17p, and NOTCH1 mutations) maintained significant associations with TTFT in a basic multivariable model, collectively yielding a Harrell's C-index of 75% and explaining 45.4% of the variance in the prediction of TTFT. Concerning miRNAs, 73 out of 513 were significantly associated with TTFT in a univariable model; of these, 16 retained an independent relationship with the outcome in a multivariable analysis. For 8 of these (i.e., miR-582-3p, miR-33a-3p, miR-516a-5p, miR-99a-5p, and miR-296-3p, miR-502-5p, miR-625-5p, and miR-29c-3p), a lower expression correlated with a shorter TTFT, whereas in the remaining eight (i.e., miR-150-5p, miR-148a-3p, miR-28-5p, miR-144-5p, miR-671-5p, miR-1-3p, miR-193a-3p, and miR-124-3p), the higher expression was associated with shorter TTFT. Integrating these miRNAs into the basic model significantly enhanced predictive accuracy, raising the Harrell's C-index to 81.1% and the explained variation in TTFT to 63.3%. Moreover, the inclusion of the miRNA scores enhanced the integrated discrimination improvement (IDI) and the net reclassification index (NRI), underscoring the potential of miRNAs to refine CLL prognostic models and providing insights for clinical decision-making. In silico analyses on the differently expressed miRNAs revealed their potential regulatory functions of several pathways, including those involved in the therapeutic responses. To add a biological context to the clinical evidence, an miRNA-mRNA correlation analysis revealed at least one significant negative correlation between 15 of the identified miRNAs and a set of 50 artificial intelligence (AI)-selected genes, previously identified by us as relevant for TTFT prediction in the same cohort of CLL patients. In conclusion, the identification of specific miRNAs as predictors of TTFT holds promise for enhancing risk stratification in CLL to predict therapeutic needs. However, further validation studies and in-depth functional analyses are required to confirm the robustness of these observations and to facilitate their translation into meaningful clinical utility.

Myeloid/lymphoid neoplasms with eosinophilia and FGFR1 rearrangement t(8;13)(p11;q12): A case report and literature review.

8p11 myeloproliferative syndrome (EMS) is a rare and aggressive hematological malignancy, characterized by myeloproliferative neoplasms, and associated with eosinophilia and T- or B-cell lineage lymphoblastic lymphoma. The pathogenesis is defined by the presence of chromosomal translocations associated with the fibroblast growth factor-1 (FGFR1) gene, located in the 8p11-12.1 chromosomal locus. At present, only ~100 cases have been reported globally. At least 15 partner genes have been identified, including the most common, the zinc finger MYM-type containing 2 (ZNF198)-FGFR1 fusion gene formed by t(8;13)(p11;q12). Different fusion genes determine the clinical manifestations and prognosis of the disease. Patients with EMS with t(8;13)(p11;q12) commonly present with lymphadenopathy and T-lymphoblastic lymphoma, which usually converts to acute myeloid leukemia (AML) with the progression of the disease. The present study describes the case of an elderly female patient with EMS with t(8;13)(p11;q12), presenting with myeloid/lymphoid syndrome (myeloproliferative neoplasms and T lymphoblastic lymphoma). The patient received the CHOPE regimen combined with tyrosine kinase inhibitor (dasatin) treatment and obtained short-term complete remission. However, 6 months later, the disease progressed from EMS to AML and the patient died due to ineffective induction therapy. The present study also reviews the relevant literature about this unusual entity to enhance the understanding of EMS.

Loss of Chromosome Y in Neuroblastoma Is Associated With High-Risk Disease, 11q-Deletion, and Telomere Maintenance.

Neuroblastoma (NB) is a heterogeneous childhood cancer with a slightly higher incidence in boys than girls, with the reason for this gender disparity unknown. Given the growing evidence for the involvement of loss of the Y chromosome (LoY) in male diseases including cancer, we investigated Y chromosome status in NB. Male NB tumor samples from a Swedish cohort, analyzed using Cytoscan HD SNP-microarray, were selected. Seventy NB tumors were analyzed for aneuploidy of the Y chromosome, and these data were correlated with other genetic, biological, and clinical parameters. LoY was found in 21% of the male NB tumors and it was almost exclusively found in those with high-risk genomic profiles. Furthermore, LoY was associated with increased age at diagnosis and enriched in tumors with 11q-deletion and activated telomere maintenance mechanisms. In contrast, tumors with an MYCN-amplified genomic profile retained their Y chromosome. The understanding of LoY in cancer is limited, making it difficult to conclude whether LoY is a driving event in NB or function of increased genomic instability. Gene expression analysis of Y chromosome genes in male NB tumors showed low expression of certain genes correlating with worse overall survival. KDM5D, encoding a histone demethylase stands out as an interesting candidate for further studies. LoY has been shown to impact the epigenomic layer of autosomal loci in nonreproductive tissues, and KDM5D has been reported as downregulated and/or associated with poor survival in different malignancies. Further studies are needed to explore the mechanisms and functional consequences of LoY in NB.

Exploring the Clinical and Genetic Landscape of Angelman Syndrome: Patient-Reported Insights from an Italian Registry.

Background: The Angelman Syndrome Registry (RISA) was developed as a retrospective study with the following objectives: to evaluate the clinical history of individuals with Angelman Syndrome (AS) in Italy and compare it with the existing literature; to investigate the feasibility of gathering data by directly involving participants in the data collection process; and to explore the relationship between different symptoms and genotypes. Methods: Established in 2018, RISA enrolled a total of 82 participants, with 62 (75.6%) providing complete data. Demographic, clinical, and genetic information was collected using electronic case report forms. Descriptive statistics characterized the sample, while associations between genotype and clinical characteristics were examined. Results: Descriptive analysis revealed a median participant age of 8.0 years, with males comprising 48.8% of the sample. Deletion (58.1%) was the most common genotype. The majority (82.2%) experienced epilepsy, with seizures typically onset before 3 years of age. Most patients (86.2%) required multiple anti-epileptic drugs for control, with generalized tonic-clonic seizures and atypical absence seizures being most prevalent. The deletion group exhibited more severe developmental delays and a trend towards higher seizure severity. Sleep problems affected 69.4% of participants, characterized by difficulties in sleep onset and maintenance. Conclusions: This study offers valuable insights into the clinical history and genetic characteristics of AS in Italy, consistent with the prior literature. Additionally, it underscores the efficacy of patient registries in capturing comprehensive data on rare diseases such as AS, highlighting their potential to advance research and enhance patient care.

Cup-like nuclei in adult B-cell acute lymphoblastic leukemia with the translocation (4;11)(q21;q23).

Cuplike Nuclei(CLN) cells, particularly rare in Acute Lymphoblastic Leukemia(ALL), have been documented in only few cases to date. A recent study has revealed a correlation between CLN and IKZF1 deletions in pediatric B-ALL. This study introduces a case of CLN in adult B-ALL with a translocation (4;11)(q21;q23), while discussing the current relevant literature on the subject. Through this examination, several unique characteristics of CLN cells in both ALL and Acute Myeloid Leukemia are highlighted. It is essential to accumulate further data to confirm these distinctive traits, and investigate the potential association between CLN and cytogenetic/molecular abnormalities.

FADD amplification is associated with CD8+ T-cell exclusion and malignant progression in HNSCC.

OBJECTIVE: This study aimed to clarify the relationship between FADD amplification and overexpression and the tumor immune microenvironment. METHODS: Immunohistochemical staining and bioanalysis were used to analyze the association between FADD expression in tumor cells and cells in tumor microenvironment. RNA-seq analysis was used to detect the differences in gene expression upon FADD overexpression. Flow cytometry and multicolor immunofluorescence staining (mIHC) were used to detect the differences in CD8+ T-cell infiltration in FADD-overexpressed cells or tumor tissues. RESULTS: Overexpression of FADD significantly promoted tumor growth. Cells with high FADD expression presented high expression of CD276 and FGFBP1 and low expression of proinflammatory factors (such as IFIT1-3 and CXCL8), which reduced the percentage of CD8+ T cells and created a "cold tumor" immune microenvironment, thus promoting tumor progression. In vivo and in vitro experiment confirmed that tumor tissues with excessive FADD expression exhibited CD8+ T-cell exclusion in the microenvironment. CONCLUSION: Our preliminary investigation has discovered the association between FADD expression and the immunosuppressive microenvironment in HNSCC. Due to the high frequent amplification of the chromosomal region 11q13.3, where FADD is located, targeting FADD holds promise for improving the immune-inactive state of tumors, subsequently inhibiting HNSCC tumor progression.

Chronic myeloproliferative neoplasm in adulthood in CBL syndrome harboring a splice-site CBL variant alongside a novel constitutional CSF3R variant.

Casitas B-cell lineage (CBL) syndrome is a rare RASopathy known to predispose to CBL-mutated juvenile myelomonocytic leukemia (JMML) in childhood. Adulthood acute myeloid leukemia arising out of a genetic aberrancies consistent with prior CBL-mutated JMML has been twice previously described, but chronic myeloproliferative neoplasia has not. We present a case of progressive myeloproliferative neoplasm in adulthood in the context of CBL syndrome alongside a novel CSF3R variant. We also review pathogenic splice-site mutations in CBL-mutated JMML.

Expanding deep phenotypic spectrum associated with atypical pathogenic structural variations overlapping 15q11-q13 imprinting region.

BACKGROUND: The 15q11-q13 region is a genetic locus with genes subject to genomic imprinting, significantly influencing neurodevelopment. Genomic imprinting is an epigenetic phenomenon that causes differential gene expression based on the parent of origin. In most diploid organisms, gene expression typically involves an equal contribution from both maternal and paternal alleles, shaping the phenotype. Nevertheless, in mammals, including humans, mice, and marsupials, the functional equivalence of parental alleles is not universally maintained. Notably, during male and female gametogenesis, parental alleles may undergo differential marking or imprinting, thereby modifying gene expression without altering the underlying DNA sequence. Neurodevelopmental disorders, such as Prader-Willi syndrome (PWS) (resulting from the absence of paternally expressed genes in this region), Angelman syndrome (AS) (associated with the absence of the maternally expressed UBE3A gene), and 15q11-q13 duplication syndrome (resulting from the two common forms of duplications-either an extra isodicentric 15 chromosome or an interstitial 15 duplication), are the outcomes of genetic variations in this imprinting region. METHODS: Conducted a genomic study to identify the frequency of pathogenic variants impacting the 15q11-q13 region in an ethnically homogenous population from Bangladesh. Screened all known disorders from the DECIPHER database and identified variant enrichment within this cohort. Using the Horizon analysis platform, performed enrichment analysis, requiring at least >60% overlap between a copy number variation and a disorder breakpoint. Deep clinical phenotyping was carried out through multiple examination sessions to evaluate a range of clinical symptoms. RESULTS: This study included eight individuals with clinically suspected PWS/AS, all previously confirmed through chromosomal microarray analysis, which revealed chromosomal breakpoints within the 15q11-q13 region. Among this cohort, six cases (75%) exhibited variable lengths of deletions, whereas two cases (25%) showed duplications. These included one type 2 duplication, one larger atypical duplication, one shorter type 2 deletion, one larger type 1 deletion, and four cases with atypical deletions. Furthermore, thorough clinical assessments led to the diagnosis of four PWS patients, two AS patients, and two individuals with 15q11-q13 duplication syndrome. CONCLUSION: Our deep phenotypic observations identified a spectrum of clinical features that overlap and are unique to PWS, AS, and Dup15q syndromes. Our findings establish genotype-phenotype correlation for patients impacted by variable structural variations within the 15q11-q13 region.

Assessment for 11q and other chromosomal aberrations in large B-cell/high-grade B cell lymphomas of germinal center phenotype lacking BCL2 expression.

The WHO classifications of hematolymphoid malignancies have recognized several distinct entities within the large B cell lymphomas, including the more recently described high-grade B cell lymphoma with 11q aberration (HGBCL-11q). We utilized genomic array to assess for chromosome 11q abnormalities in a broad set of aggressive B cell lymphomas from 27 patients with a focus on younger adults. The findings suggest more frequent alterations of 11q in diffuse large B cell lymphoma (DLBCL)/HGBCL-GC BCL2-, in comparison to cases of Burkitt lymphoma (BL) or DLBCL-GC BCL2+, and confirm a low genomic complexity score of BL. Variability identified in patterns of 11q alterations suggests genomic array studies may afford value over FISH testing as we continue to understand HGBCL-11q as a distinct entity, and interrogate cases of DLBCL/HGBCL-GC BCL2-.

Aggressive B-cell non-Hodgkin lymphomas: a report of the lymphoma workshop of the 20th meeting of the European Association for Haematopathology.

Aggressive B-cell non-Hodgkin lymphomas are a heterogeneous group of diseases and our concepts are evolving as we learn more about their clinical, pathologic, molecular genetic features. Session IV of the 2020 EAHP Workshop covered aggressive, predominantly high-grade B-cell lymphomas, many that were difficult to classify. In this manuscript, we summarize the features of the submitted cases and highlight differential diagnostic difficulties. We specifically review issues related to high-grade B-cell lymphomas (HGBCLs) with MYC and BCL2 and/or BCL6 rearrangements including TdT expression in these cases, HGBCL, not otherwise specified, large B-cell lymphomas with IRF4 rearrangement, high-grade/large B-cell lymphomas with 11q aberration, Burkitt lymphoma, and pleomorphic mantle cell lymphoma. Since the workshop, the 5th edition of the WHO Classification for Haematolymphoid Tumours (WHO-HAEM5) and International Consensus Classification (ICC) 2022 were published. We endeavor to use the updated terminology.

Cytogenomic features of Richter transformation.

BACKGROUND: Richter transformation (RT) is the development of aggressive lymphoma in patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL). This rare disease is characterised by dismal prognosis. In recent years, there has been a deeper understanding of RT molecular pathogenesis, and disruptions of apoptosis (TP53) and proliferation (CDKN2A, MYC, NOTCH1) has been described as typical aberrations in RT. RESULTS: A single-institution cohort of 33 RT patients were investigated by karyotyping, fluorescence in situ hybridization and single nucleotide polymorphism/copy number (CN) arrays. Most of RTs were typically manifested by diffuse large B-cell lymphoma, not otherwise specified, among the remaining cases one was classified as high-grade B-cell lymphoma with 11q aberrations. The most frequent alterations (40-60% of cases) were represented by MYC rearrangement/gain, deletions of TP53 and CDKN2A, IGH rearrangement and 13q14 deletion. Several other frequent lesions included losses of 14q24.1-q32.33, 7q31.33-q36.3, and gain of 5q35.2. Analysis of 13 CLL/SLL-RT pairs showed that RT arised from the CLL/SLL by acquiring of 10 ~ 12 cytogenetic or CN lesions/case, but without acquisition of loss of heterozygosity regions. Our result affirmed the higher genetic complexity in RT than CLL/SLL and confirmed the linear features of RT clonal evolution as predominant. CONCLUSIONS: Cytogenomic profile was concordant with the literature data, however the role of IGH rearrangement, 14q deletion and 5q35.2 gain need to be explored. We anticipate that further characterization of RT lesions will probably facilitate better understanding of the RT clonal evolution.

A Review of Childhood Acute Myeloid Leukemia: Diagnosis and Novel Treatment.

Acute myeloid leukemia (AML) is the second most common hematologic malignancy in children. The incidence of childhood AML is much lower than acute lymphoblastic leukemia (ALL), which makes childhood AML a rare disease in children. The role of genetic abnormalities in AML classification, management, and prognosis prediction is much more important than before. Disease classifications and risk group classifications, such as the WHO classification, the international consensus classification (ICC), and the European LeukemiaNet (ELN) classification, were revised in 2022. The application of the new information in childhood AML will be upcoming in the next few years. The frequency of each genetic abnormality in adult and childhood AML is different; therefore, in this review, we emphasize well-known genetic subtypes in childhood AML, including core-binding factor AML (CBF AML), KMT2Ar (KMT2A/11q23 rearrangement) AML, normal karyotype AML with somatic mutations, unbalanced cytogenetic abnormalities AML, NUP98 11p15/NUP09 rearrangement AML, and acute promyelocytic leukemia (APL). Current risk group classification, the management algorithm in childhood AML, and novel treatment modalities such as targeted therapy, immune therapy, and chimeric antigen receptor (CAR) T-cell therapy are reviewed. Finally, the indications of hematopoietic stem cell transplantation (HSCT) in AML are discussed.

Pathogenetic Dichotomy in Angioleiomyoma.

BACKGROUND/AIM: Angioleiomyoma is a benign tumor, occurs at any age, and arises most frequently in the lower extremities. Genetic information on angioleiomyomas is restricted to six reported abnormal karyotypes, losses in chromosome 22 and gains in Xq found by comparative genomic hybridization, and mutation analysis of notch receptor 2 (NOTCH2), NOTCH3, platelet-derived growth factor receptor beta (PDGFRB), and mediator complex subunit 12 (MED12) in a few tumors. Herein, we report the genetic findings in another three angioleiomyomas. MATERIALS AND METHODS: The tumors were examined using G-banding and karyotyping, RNA sequencing, reverse transcription-polymerase chain reaction, Sanger sequencing, and expression analysis. RESULTS: The first tumor carried a t(4;5)(p12;q32) translocation resulting in fusion of the cardiac mesoderm enhancer-associated non-coding RNA (CARMN in 5q32) with the TXK tyrosine kinase gene (TXK in 4p12) leading to overexpression of TXK. To our knowledge, this is the first time that a recurrent chromosome translocation and its resulting fusion gene have been described in angioleiomyomas. The second tumor carried a four-way translocation, t(X;3;4;16)(q22;p11;q11;p13) which fused the myosin heavy chain 11 gene (MYH11 in 16p13) with intergenic sequences from Xq22 that mapped a few kilobase pairs distal to the insulin receptor substrate 4 gene (IRS4), resulting in enhanced IRS4 expression. The third angioleiomyoma carried another rearrangement of chromosome band Xq22, t(X;9)(q22;q32), as the sole cytogenetic aberration, but no material was available for further molecular investigation. CONCLUSION: Our data, together with previously reported abnormal karyotypes in angioleiomyomas, show the presence of two recurrent genetic pathways in this tumor type: The first is characterized by presence of the translocation t(4;5)(p12;q32), which generates a CARMN::TXK chimera. The second is recurrent rearrangement of Xq22 resulting in overexpression of IRS4.

Pure Interstitial Trisomy 11q Arising from a Nonrecurrent 11q13.1q22.3 Mosaic Intrachromosomal Duplication in a Patient with Craniofacial Dysmorphism and Genital Anomalies.

Introduction: The pure interstitial trisomy 11q11q23.2 is an uncommon genomic disorder associated with nonrecurrent intrachromosomal duplications. The phenotype is characterized by intellectual disability and craniofacial abnormalities. Given their uncommonness, a comprehensive genotype-phenotype correlation has not fully been defined. Case Presentation: We report the clinical and cytogenomic characterization of a 5-year-old boy with intellectual disability, psychomotor retardation, craniofacial dysmorphism, genital anomalies, and pure interstitial trisomy 11q arising from a nonrecurrent 11q13.1q22.3 intrachromosomal duplication in a high-mosaic state (>80%). The duplicated chromosome was characterized by cytogenetics, multicolor banding FISH, and SNP array. We demonstrated the wide mosaic distribution of the 11q duplication by interphase FISH in tissues from different embryonic germ layers. The duplication involves a copy number gain of 45.3 Mb containing 22 dosage-sensitive genes. We confirmed the overexpression of dosage-sensitive genes along the duplicated region using RT-qPCR. Discussion: Only 8 patients have been described. Our patient shares clinical features with previous reports but differs from them by the presence of genital anomalies. We provide a detailed clinical review and an accurate genotype-phenotype correlation and propose PC, NDUFV1, FGF3, FGF4, and DHCR7 as dosage-sensitive genes with a possible role in the clinical spectrum of our patient; however, expression changes of FGF3/4 were not detected since they must be regulated in a spatiotemporal way. This patient contributes to the accurate description of the pure interstitial trisomy 11q. Future reports could continue to delineate the description, considering the relationship between the chromosome segment and the genes involved.

Emerging entities: high-grade/large B-cell lymphoma with 11q aberration, large B-cell lymphoma with IRF4 rearrangement, and new molecular subgroups in large B-cell lymphomas. A report of the 2022 EA4HP/SH lymphoma workshop.

Emerging entities and molecular subgroups in large B-cell lymphomas (LBCLs) were discussed during the 2022 European Association for Haematopathology/Society for Hematopathology workshop in Florence, Italy. This session focused on newly recognized diseases and their diagnostic challenges. High-grade/large B-cell lymphoma with 11q aberration (HG/LBCL-11q) is defined by chromosome 11q-gains and telomeric loss. FISH analysis is recommended for the diagnosis. HG/LBCL-11q can occur in the setting of immunodeficiency, including ataxia-telangiectasia, and predominates in children. The morphological spectrum of these cases is broader than previously thought with often Burkitt-like morphology and coarse apoptotic bodies. It has a Burkitt-like immunophenotype (CD10+, BCL6+, BCL2-) but MYC expression is weak or negative, lacks MYC rearrangement, and is in contrast to Burkitt lymphoma 50% of the cases express LMO2. LBCL with IRF4 rearrangement (LBCL-IRF4) occurs mainly in the pediatric population but also in adults. LBCL-IRF4 has an excellent prognosis, with distinguishing molecular findings. IRF4 rearrangements, although characteristic of this entity, are not specific and can be found in association with other chromosomal translocations in other large B-cell lymphomas. Other molecular subgroups discussed included primary bone diffuse large B-cell lymphoma (PB-DLBCL), which has distinctive clinical presentation and molecular findings, and B-acute lymphoblastic leukemia (B-ALL) with IGH::MYC translocation recently segregated from Burkitt lymphoma with TdT expression. This latter disorder has molecular features of precursor B-cells, often tetrasomy 1q and recurrent NRAS and KRAS mutations. In this report, novel findings, recommendations for diagnosis, open questions, and diagnostic challenges raised by the cases submitted to the workshop will be discussed.

ETS1 phosphorylation at threonine 38 is associated with the cell of origin of diffuse large B cell lymphoma and sustains the growth of tumour cells.

The transcriptional factor ETS1 is upregulated in 25% of diffuse large B cell lymphoma (DLBCL). Here, we studied the role of ETS1 phosphorylation at threonine 38, a marker for ETS1 activation, in DLBCL cellular models and clinical specimens. p-ETS1 was detected in activated B cell-like DLBCL (ABC), not in germinal centre B-cell-like DLBCL (GCB) cell lines and, accordingly, it was more common in ABC than GCB DLBCL diagnostic biopsies. MEK inhibition decreased both baseline and IgM stimulation-induced p-ETS1 levels. Genetic inhibition of phosphorylation of ETS1 at threonine 38 affected the growth and the BCR-mediated transcriptome program in DLBCL cell lines. Our data demonstrate that ETS1 phosphorylation at threonine 38 is important for the growth of DLBCL cells and its pharmacological inhibition could benefit lymphoma patients.

[«Malignant stroma?¼ Alternative localization of classical genetic aberrations in neuroblastoma]. / Zlokachestvennaya stroma? Al'ternativnaya lokalizatsiya klassicheskikh geneticheskikh aberratsii v neiroblastome.

Neuroblastoma (NB) is a malignant neoplasm originating from the primary cells of the sympathetic nervous system. Patients with NB are risk-stratified using a number of features including age at diagnosis, disease stage, tumor histology and genetic profile (status of NMYC, ALK genes, regions 1p and 11q). The interpretation of the results of genetic studies can become a source of problems because neuroblastoma has a heterogeneous histological pattern. The article describes 2 cases with classical for NB chromosomal aberrations in the stromal component of the tumor.

Genetic Pathways in Peritoneal Mesothelioma Tumorigenesis.

BACKGROUND/AIM: Mesotheliomas are tumors similar to, and probably derived from, mesothelial cells. They carry acquired chromosomal rearrangements, deletions affecting CDKN2A, pathogenetic polymorphisms in NF2, and fusion genes which often contain the promiscuous EWSR1, FUS, and ALK as partner genes. Here, we report the cytogenomic results on two peritoneal mesotheliomas. MATERIALS AND METHODS: Both tumors were examined using G-banding with karyotyping and array comparative genomic hybridization (aCGH). One of them was further investigated with RNA sequencing, reverse transcription polymerase chain reaction (RT-PCR), Sanger sequencing, and fluorescence in situ hybridization (FISH). RESULTS: In the first mesothelioma, the karyotype was 25∼26,X,+5,+7,+20[cp4]/50∼52,idemx2[cp7]/46,XX[2]. aCGH detected gains of chromosomes 5, 7, and 20 with retained heterozygosity on these chromosomes. In the second tumor, the karyotype was 46,XX,inv(10)(p11q25)[7]/46,XX[3]. aCGH did not detect any gains or losses and showed heterozygosity for all chromosomes. RNA sequencing, RT-PCR/Sanger sequencing, and FISH showed that the inv(10) fused MAP3K8 from 10p11 with ABLIM1 from 10q25. The MAP3K8::ABLIM1 chimera lacked exon 9 of MAP3K8. CONCLUSION: Our data, together with information on previously described mesotheliomas, illustrate two pathogenetic mechanisms in peritoneal mesothelioma: One pathway is characterized by hyperhaploidy, but with retained disomies for chromosomes 5, 7, and 20; this may be particularly prevalent in biphasic mesotheliomas. The second pathway is characterized by rearrangements of MAP3K8 from which exon 9 of MAP3K8 is lost. The absence of exon 9 from oncogenetically rearranged MAP3K8 is a common theme in thyroid carcinoma, lung cancer, and spitzoid as well as other melanoma subtypes.