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In this study, investigators compared genome sequencing with cytogenetic analysis in 263 patients with acute myeloid leukemia or myelodysplastic syndromes. Prospective sequencing detected new genetic information that was not revealed by cytogenetic analysis in nearly 25% of the patients, which altered the risk category for most of these patients.

Hematopoietic clones harboring specific mutations may expand over time. However, it remains unclear how different cellular stressors influence this expansion. Here we characterize clonal hematopoiesis after two different cellular stressors: cytotoxic therapy and hematopoietic transplantation. Cytotoxic therapy results in the expansion of clones carrying mutations in DNA damage response genes, including TP53 and PPM1D . Analyses of sorted populations show that these clones are typically multilineage and myeloid-biased. Following autologous transplantation, most clones persist with stable chimerism. However, DNMT3A mutant clones often expand, while PPM1D mutant clones often decrease in size. To assess the leukemic potential of these expanded clones, we genotyped 134 t-AML/t-MDS samples. Mutations in non- TP53 DNA damage response genes are infrequent in t-AML/t-MDS despite several being commonly identified after cytotoxic therapy. These data suggest that different hematopoietic stressors promote the expansion of distinct long-lived clones, carrying specific mutations, whose leukemic potential depends partially on the mutations they harbor. Cellular stressors can impact clonal hematopoiesis. Here, the authors explore the impact of cytotoxic therapy and hematopoietic transplantation on clonal expansion, suggesting different stressors can promote expansion of distinct long-lived clones.

Whole-genome sequencing of samples from seven subjects with secondary acute myeloid leukemia identified somatic mutations. These data, together with genotype analysis of the antecedent myelodysplastic syndromes (MDS), revealed the clonal evolution of MDS and secondary AML. The myelodysplastic syndromes, a heterogeneous group of diseases characterized by ineffective hematopoiesis, are the most common cause of acquired bone marrow failure in adults. 1 Secondary acute myeloid leukemia (AML) develops in approximately one third of persons with myelodysplastic syndromes. 2 Clinical discrimination between the myelodysplastic syndromes and secondary AML currently rests predominantly on cytomorphologic analysis, since patients with myelodysplastic syndromes have dysplastic hematopoiesis and a myeloblast count of less than 20%, whereas those with a myeloblast count of 20% or more have AML. Although considerable overlap exists between the spectrum of cytogenetic and molecular lesions seen in the two disorders, there . . .

Tumor lysis syndrome (TLS) is widely recognized as a serious adverse event associated with the cytotoxic therapies primarily used in hematologic cancers, such as Burkitt lymphoma and acute lymphoblastic leukemia. In recent years, TLS has been more widely observed, due at least in part to the availability of more effective cancer treatments. Moreover, TLS is seen with greater frequency in solid tumors, and particularly in bulky tumors with extensive metastases and tumors with organ or bone marrow involvement. The consequences of TLS include the serious morbidity and high risk of mortality associated with the condition itself. Additionally, TLS may delay or force an alteration in the patient’s chemotherapy regimen. The changing patterns of TLS, as well as its frequency, in the clinical setting, result in unnecessarily high rates of illness and/or fatality. Prophylactic measures are widely available for patients at risk of TLS, and are considered highly effective. The present article discusses the various manifestations of TLS, its risk factors and management options to prevent TLS from occurring.

Matthew Walter and colleagues report the whole-genome sequencing of a secondary acute myeloid leukemia sample and a matched normal tissue sample. Further analysis of additional subjects identified recurrent mutations in U2AF1 in 13/150 (8.7%) individuals with myelodysplastic syndrome. Myelodysplastic syndromes (MDS) are hematopoietic stem cell disorders that often progress to chemotherapy-resistant secondary acute myeloid leukemia (sAML). We used whole-genome sequencing to perform an unbiased comprehensive screen to discover the somatic mutations in a sample from an individual with sAML and genotyped the loci containing these mutations in the matched MDS sample. Here we show that a missense mutation affecting the serine at codon 34 (Ser34) in U2AF1 was recurrently present in 13 out of 150 (8.7%) subjects with de novo MDS, and we found suggestive evidence of an increased risk of progression to sAML associated with this mutation. U2AF1 is a U2 auxiliary factor protein that recognizes the AG splice acceptor dinucleotide at the 3′ end of introns, and the alterations in U2AF1 are located in highly conserved zinc fingers of this protein 1 , 2 . Mutant U2AF1 promotes enhanced splicing and exon skipping in reporter assays in vitro . This previously unidentified, recurrent mutation in U2AF1 implicates altered pre-mRNA splicing as a potential mechanism for MDS pathogenesis.

Next-generation sequencing has been used to infer the clonality of heterogeneous tumor samples. These analyses yield specific predictions-the population frequency of individual clones, their genetic composition, and their evolutionary relationships-which we set out to test by sequencing individual cells from three subjects diagnosed with secondary acute myeloid leukemia, each of whom had been previously characterized by whole genome sequencing of unfractionated tumor samples. Single-cell mutation profiling strongly supported the clonal architecture implied by the analysis of bulk material. In addition, it resolved the clonal assignment of single nucleotide variants that had been initially ambiguous and identified areas of previously unappreciated complexity. Accordingly, we find that many of the key assumptions underlying the analysis of tumor clonality by deep sequencing of unfractionated material are valid. Furthermore, we illustrate a single-cell sequencing strategy for interrogating the clonal relationships among known variants that is cost-effective, scalable, and adaptable to the analysis of both hematopoietic and solid tumors, or any heterogeneous population of cells.

Cytogenetic analysis of acute myeloid leukemia (AML) cells has accelerated the identification of genes important for AML pathogenesis. To complement cytogenetic studies and to identify genes altered in AML genomes, we performed genome-wide copy number analysis with paired normal and tumor DNA obtained from 86 adult patients with de novo AML using 1.85 million feature SNP arrays. Acquired copy number alterations (CNAs) were confirmed using an ultra-dense array comparative genomic hybridization platform. A total of 201 somatic CNAs were found in the 86 AML genomes (mean, 2.34 CNAs per genome), with French-American-British system M6 and M7 genomes containing the most changes (10-29 CNAs per genome). Twenty-four percent of AML patients with normal cytogenetics had CNA, whereas 40% of patients with an abnormal karyotype had additional CNA detected by SNP array, and several CNA regions were recurrent. The mRNA expression levels of 57 genes were significantly altered in 27 of 50 recurrent CNA regions <5 megabases in size. A total of 8 uniparental disomy (UPD) segments were identified in the 86 genomes; 6 of 8 UPD calls occurred in samples with a normal karyotype. Collectively, 34 of 86 AML genomes (40%) contained alterations not found with cytogenetics, and 98% of these regions contained genes. Of 86 genomes, 43 (50%) had no CNA or UPD at this level of resolution. In this study of 86 adult AML genomes, the use of an unbiased high-resolution genomic screen identified many genes not previously implicated in AML that may be relevant for pathogenesis, along with many known oncogenes and tumor suppressor genes.

BackgroundCutaneous squamous cell carcinoma (cSCC) is not uncommon in association with indolent malignancies that were treated with prior radiotherapy and after allogenic bone marrow transplantation. On the other hand, cutaneous T-cell lymphoma (CTCL) is a subtype of non-Hodgkin’s lymphoma which is characterized by an indolent course, with relative refractoriness to conventional chemotherapies and radiotherapy, and occasionally referred for allogeneic hematopoietic cell transplantation (allo-HCT). Recently, the use of immune checkpoint inhibitors has gained attention in the treatment of both cutaneous squamous cell carcinoma and hematological malignancies. However, many patients with hematological malignancies eventually undergo allo-HCT, raising the concern of potential adverse events (graft versus host disease) due to manipulation of the immune system with use of checkpoint inhibitors.Case presentationWe describe a patient with relapsed refractory CTCL (Sézary Syndrome) who underwent allo-HCT with persistence of disease post-transplant. The patient additionally developed a progressively worsening lesion on the right shoulder which was biopsied and showed poorly differentiated carcinoma (cSCC). Pembrolizumab was started for the treatment of cSCC. After second cycle of treatment, the cSCC lesion responded dramatically to the use of immune checkpoint inhibitor. Also, the patient experienced significant resolution of pruritus and generalized erythema. During 24 months of follow up after initial treatment with checkpoint inhibition immunotherapy, the patient showed durable response of both cSCC and CTCL, as well as restoration of full donor chimerism, without obvious worsening of graft versus host disease (GVHD).ConclusionThis is the first case to our knowledge of rapid and durable response of both cSCC and CTCL to immune checkpoint inhibition after allo-HCT. Although this report highlights the potential for significant response to this class of medication, further studies are required to confirm the efficacy and safety of this approach in patients with CTCL after allo-HCT given the potential concern of GVHD.

We conducted a phase I study using midostaurin (25 or 50 mg orally twice daily), all- trans retinoic acid (ATRA) and CLAG chemotherapy to target multiple pathways in relapsed/refractory AML. 10 patients received the combination and no dose-limiting toxicities were observed. Two patients (22 %) achieved complete remission and 1 patient (11 %) achieved complete remission with incomplete count recovery. Pharmacokinetic data showed that the 25 mg dosing of midostaurin achieved therapeutic levels with no significant interaction between midostaurin and ATRA. With evidence of activity of ATRA in NPM1-mutated AML and midostaurin in FLT3-ITD AML, this combination warrants further investigation.

Posttransplant Lymphoproliferative Disorder (PTLD) is one of the most common malignancies complicating solid organ transplantation. In contrast, PTLD accounts for a minority of secondary cancers following allogeneic hematopoietic cell transplantation (HCT). Here we report on a 61-year-old woman who received an ABO-mismatched, HLA-matched unrelated donor hematopoietic cell transplantation from a presumably healthy donor for a diagnosis of acute myeloid leukemia (AML). Eighteen months following her transplant, she developed a monoclonal gammopathy. Bone marrow studies revealed 10% plasma cells, but the patient lacked clinical defining features of multiple myeloma (MM); thus a diagnosis of smoldering multiple myeloma (SMM) was established. Cytogenetic and molecular studies of the bone marrow confirmed the plasma cells were donor-derived. The donor lacks a diagnosis of monoclonal gammopathy of undetermined significance, SMM, or MM.