Cas9-directed long-read sequencing to resolve optical genome mapping findings in leukemia diagnostics.

Leukemias are genetically heterogeneous and diagnostics therefore includes various standard-of-care (SOC) techniques, including karyotyping, SNP-array and FISH. Optical genome mapping (OGM) may replace these as it detects different types of structural aberrations simultaneously and additionally detects much smaller aberrations (500 bp vs 5-10 Mb with karyotyping). However, its resolution may still be too low to define clinical relevance of aberrations when they are located between two OGM labels or when labels are not distinct enough.

Transcriptomic subtyping of malignant peripheral nerve sheath tumours highlights immune signatures, genomic profiles, patient survival and therapeutic targets.

Background: Malignant peripheral nerve sheath tumour (MPNST) is an aggressive orphan disease commonly affecting adolescents or young adults. Current knowledge of molecular tumour biology has been insufficient for development of rational treatment strategies. We aimed to discover molecular subtypes of potential clinical relevance.

Comorbidities and malignancies negatively affect survival in myelodysplastic syndromes: a population-based study.

Population-based studies that contain detailed clinical data on patients with myelodysplastic syndrome (MDS) are scarce. This study focused on the real-world overall survival (OS) of MDS patients in association with comorbidities, specifically malignancies. An observational population-based study using the HemoBase registry was performed, including all patients with MDS diagnosed between 2005 and 2017 in Friesland, a Dutch province.

Mantle cell lymphomas with concomitant MYC and CCND1 breakpoints are recurrently TdT positive and frequently show high-grade pathological and genetic features.

Chromosomal breakpoints involving the MYC gene locus, frequently referred to as MYC rearrangements (MYC - R+), are a diagnostic hallmark of Burkitt lymphoma and recurrent in many other subtypes of B-cell lymphomas including follicular lymphoma, diffuse large B-cell lymphoma and other high-grade B-cell lymphomas and are associated with an aggressive clinical course. In remarkable contrast, in MCL, only few MYC - R+ cases have yet been described. In the current study, we have retrospectively analysed 16 samples (MYC - R+, n = 15, MYC - R-, n = 1) from 13 patients and describe their morphological, immunophenotypic and (molecular) genetic features and clonal evolution patterns.

Targeted RNA-Sequencing Enables Detection of Relevant Translocations and Single Nucleotide Variants and Provides a Method for Classification of Hematological Malignancies-RANKING.

Background: Patients with hematological malignancies (HMs) carry a wide range of chromosomal and molecular abnormalities that impact their prognosis and treatment. Since no current technique can detect all relevant abnormalities, technique(s) are chosen depending on the reason for referral, and abnormalities can be missed. We tested targeted transcriptome sequencing as a single platform to detect all relevant abnormalities and compared it to current techniques.

Detection of Fusion Genes to Determine Minimal Residual Disease in Leukemia Using Next-Generation Sequencing.

Background: Measuring minimal residual disease (MRD), the persistence of leukemic cells after treatment, is important for monitoring leukemia recurrence. The current methods for monitoring MRD are flow cytometry, to assess aberrant immune phenotypes, and digital droplet PCR (ddPCR), to target genetic aberrations such as single-nucleotide variants and gene fusions. We present the performance of an RNA-based next-generation sequencing (NGS) method for MRD gene fusion detection compared with ddPCR.

Ring sideroblasts in AML are associated with adverse risk characteristics and have a distinct gene expression pattern.

Ring sideroblasts (RS) emerge as result of aberrant erythroid differentiation leading to excessive mitochondrial iron accumulation, a characteristic feature for myelodysplastic syndromes (MDS) with mutations in the spliceosome gene SF3B1. However, RS can also be observed in patients diagnosed with acute myeloid leukemia (AML). The objective of this study was to characterize RS in patients with AML.

Not type of induction therapy but consolidation with allogeneic hematopoietic cell transplantation determines outcome in older AML patients: A single center experience of 355 consecutive patients.

Therapeutic decision making is often challenging in older AML patients. We collected retrospective data of 355 consecutive AML patients (≥60 years) who were treated with intensive chemotherapy (IC) (n = 155), hypomethylating agents (HMA) (n = 83), or best supportive care (BSC) (n = 117) between 2002 and 2017. Overall survival (OS) and response rates after therapy were analyzed.

Low-grade central fibroblastic osteosarcoma may be differentiated from its mimicker desmoplastic fibroma by genetic analysis.

Background: We studied two cases of rare fibrous bone tumors, namely desmoplastic fibroma (DF) and low-grade central osteosarcoma (LGCOS) resembling desmoplastic fibroma (DF-like LGCOS). As the clinical presentation, imaging features and histopathology of DF and DF-like LGOS show much overlap, the objective of this study was to investigate the value of cytogenetic analysis, molecular pathology and immunohistochemistry in discrimination of these two mimickers.

Case Presentation: A mutation in (S45F) and nuclear beta-catenin immunostaining were observed in DF.

Inferior survival for patients with malignant peripheral nerve sheath tumors defined by aberrant TP53.

Malignant peripheral nerve sheath tumor is a rare and aggressive disease with poor treatment response, mainly affecting adolescents and young adults. Few molecular biomarkers are used in the management of this cancer type, and although TP53 is one of few recurrently mutated genes in malignant peripheral nerve sheath tumor, the mutation prevalence and the corresponding clinical value of the TP53 network remains unsettled. We present a multi-level molecular study focused on aberrations in the TP53 network in relation to patient outcome in a series of malignant peripheral nerve sheath tumors from 100 patients and 38 neurofibromas, including TP53 sequencing, high-resolution copy number analyses of TP53 and MDM2, and gene expression profiling.

Genetic Screening Test to Detect Translocations in Acute Leukemias by Use of Targeted Locus Amplification.

Background: Over 500 translocations have been identified in acute leukemia. To detect them, most diagnostic laboratories use karyotyping, fluorescent in situ hybridization, and reverse transcription PCR. Targeted locus amplification (TLA), a technique using next-generation sequencing, now allows detection of the translocation partner of a specific gene, regardless of its chromosomal origin.

Early detection and evolution of preleukemic clones in therapy-related myeloid neoplasms following autologous SCT.

Therapy-related myeloid neoplasms (tMNs) are severe adverse events that can occur after treatment with autologous hematopoietic stem cell transplantation (ASCT). This study aimed to investigate the development of tMNs following ASCT at the molecular level by whole-exome sequencing (WES) and targeted deep sequencing (TDS) in sequential (pre-) tMN samples. WES identified a significantly higher number of mutations in tMNs as compared with de novo myelodysplastic syndrome (MDS) (median 27 vs 12 mutations; = .

MYC expression and translocation analyses in low-grade and transformed follicular lymphoma.

Aims: Low-grade follicular lymphoma (FL) (grade 1/2, FL1/2) has an annual risk of transformation of ≈3%, which is associated with aberrations in CDKN2A/B, TP53, and MYC. As in diffuse large B-cell lymphoma, high MYC expression in transformed FL (tFL) might predict a MYC breakpoint.

Methods And Results: We quantified MYC expression by immunohistochemistry and digital analysis in 41 paired biopsies from 20 patients with FL1/2 with subsequent transformation and in four isolated biopsies of tFL.

Guidelines for genomic array analysis in acquired haematological neoplastic disorders.

Genetic profiling is important for disease evaluation and prediction of prognosis or responsiveness to therapy in neoplasia. Microarray technologies, including array comparative genomic hybridization and single-nucleotide polymorphism-detecting arrays, have in recent years been introduced into the diagnostic setting for specific types of haematological malignancies and solid tumours. It can be used as a complementary test or depending on the neoplasia investigated, also as a standalone test.

Targeted sequencing by proximity ligation for comprehensive variant detection and local haplotyping.

Despite developments in targeted gene sequencing and whole-genome analysis techniques, the robust detection of all genetic variation, including structural variants, in and around genes of interest and in an allele-specific manner remains a challenge. Here we present targeted locus amplification (TLA), a strategy to selectively amplify and sequence entire genes on the basis of the crosslinking of physically proximal sequences. We show that, unlike other targeted re-sequencing methods, TLA works without detailed prior locus information, as one or a few primer pairs are sufficient for sequencing tens to hundreds of kilobases of surrounding DNA.

Methylated RASSF1A in malignant peripheral nerve sheath tumors identifies neurofibromatosis type 1 patients with inferior prognosis.

Background: Malignant peripheral nerve sheath tumor (MPNST) is a rare and highly aggressive disease with no evidence of effect from adjuvant therapy. It is further associated with the hereditary syndrome neurofibromatosis type 1 (NF1). Silencing of the tumor suppressor gene RASSF1A through DNA promoter hypermethylation is known to be involved in cancer development, but its impact in MPNSTs remains unsettled.

Identification of prognostic relevant chromosomal abnormalities in chronic lymphocytic leukemia using microarray-based genomic profiling.

Background: Characteristic genomic abnormalities in patients with B cell chronic lymphocytic leukemia (CLL) have been shown to provide important prognostic information. Fluorescence in situ hybridization (FISH) and multiplex ligation-dependent probe amplification (MLPA), currently used in clinical diagnostics of CLL, are targeted tests aimed at specific genomic loci. Microarray-based genomic profiling is a new high-resolution tool that enables genome-wide analyses.

A single center analysis of nucleophosmin in acute myeloid leukemia: value of combining immunohistochemistry with molecular mutation analysis.

Mutations of nucleophosmin 1 are frequently found in acute myeloid leukemia and lead to aberrant cytoplasmic accumulation of nucleophosmin protein. Immunohistochemical staining is therefore recommended as the technique of choice in front-line screening. In this study, we assessed the sensitivity and specificity of immunohistochemistry on formalin-fixed bone marrow biopsies compared with gold standard molecular analysis to predict nucleophosmin 1 mutation status in 119 patients with acute myeloid leukemia.

Azacitidine might be beneficial in a subgroup of older AML patients compared to intensive chemotherapy: a single centre retrospective study of 227 consecutive patients.

Background: Treatment options in older acute myeloid leukaemia (AML) patients include intensive chemotherapy, best supportive care (BSC), and hypomethylating agents. Currently, limited data is available on hypomethylating agents in older AML patients in unselected patient populations.

Methods: To compare the effectiveness of azacitidine with conventional therapy, we collected data of 227 consecutive AML patients (≥60 years) who were treated with azacitidine (N = 26), intensive chemotherapy (N = 90), or BSC (N = 97).

The entire miR-200 seed family is strongly deregulated in clear cell renal cell cancer compared to the proximal tubular epithelial cells of the kidney.

Despite numerous studies reporting deregulated microRNA (miRNA) and gene expression patterns in clear cell renal cell carcinoma (ccRCC), no direct comparisons have been made to its presumed normal counterpart: the renal proximal tubular epithelial cells (PTECs). The aim of this study was to determine the miRNA expression profiles of 10 ccRCC-derived cell lines and short-term cultures of PTEC and to correlate these with their gene expression and copy-number profiles. Using microarray-based methods, a significantly altered expression level in ccRCC cell lines was observed for 23 miRNAs and 1630 genes.

Targeted exome sequencing in clear cell renal cell carcinoma tumors suggests aberrant chromatin regulation as a crucial step in ccRCC development.

Clear cell renal cell carcinomas are characterized by 3p loss, and by inactivation of Von Hippel Lindau (VHL), a tumorsuppressor gene located at 3p25. Recently, SETD2, located at 3p21, was identified as a new candidate ccRCC tumor-suppressor gene. The combined mutational frequency in ccRCC tumors of VHL and SETD2 suggests that there are still undiscovered tumor-suppressor genes on 3p.

Microarray-based genomic profiling as a diagnostic tool in acute lymphoblastic leukemia.

In acute lymphoblastic leukemia (ALL) specific genomic abnormalities provide important clinical information. In most routine clinical diagnostic laboratories conventional karyotyping, in conjunction with targeted screens using e.g.