T cell receptor-engineered T cells derived from target human leukocyte antigen-DPB1-specific T cell can be a potential tool for therapy against leukemia relapse following allogeneic hematopoietic cell transplantation.

Human leukocyte antigen (HLA)-DPB1 antigens are mismatched in approximately 70% of allogeneic hematopoietic stem cell transplantations (allo-HSCT) from HLA 10/10 matched unrelated donors. HLA-DP-mismatched transplantation was shown to be associated with an increase in acute graft-versus-host disease (GVHD) and a decreased risk of leukemia relapse due to the graft-versus-leukemia (GVL) effect. Immunotherapy targeting mismatched HLA-DP is considered reasonable to treat leukemia following allo-HCT if performed under non-inflammatory conditions. Therefore, we isolated CD4+ T cell clones that recognize mismatched HLA-DPB1 from healthy volunteer donors and generated T cell receptor (TCR)-gene-modified T cells for future clinical applications. Detailed analysis of TCR-T cells expressing TCR from candidate clone #17 demonstrated specificity to myeloid and monocytic leukemia cell lines that even expressed low levels of targeted HLA-DP. However, they did not react to non-hematopoietic cell lines with a substantial level of targeted HLA-DP expression, suggesting that the TCR recognized antigenic peptide is only present in some hematopoietic cells. This study demonstrated that induction of T cells specific for HLA-DP, consisting of hematopoietic cell lineage-derived peptide and redirection of T cells with cloned TCR cDNA by gene transfer, is feasible when using careful specificity analysis.

[Hematological immune-related adverse events of immune checkpoint inhibitors and their management].

Immune checkpoints suppress inappropriate immune responses to self-molecules or cells. Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death protein 1 (PD-1) expressed in T cells are representative molecules involved in the immune checkpoint system. The recent advent of immune checkpoint inhibitors (ICIs) has drastically changed cancer immunotherapy because a substantial proportion of patients with advanced cancers have responded to ICIs and some of them have been cured. This benefit is due to T-cell rescue from immune suppression in their tumor microenvironment by blocking cluster of differentiation 80/CTLA-4 and PD-L1/PD-1 interactions. However, blocking these interactions also liberates T cells that are reactive to self-antigens from tolerance, resulting in the occurrence of autoimmune diseases, that is, immune-related adverse events. Although the primary target organs are the lungs, gastrointestinal tract, and endocrine glands, hematopoietic cells are also affected in 0.5-3% of patients, potentially resulting in anemia or thrombocytopenia. Because hematopoietic system homeostasis is critical to maintaining life support, the occurrence of grade 3-4 irAEs in the hematopoietic system is directly life-threatening. Herein, we review the relationship between ICIs and toxicities in patients with cancer and describe the characteristics and management strategies for hematological immune-related adverse events.

Development of TCR-T cell therapy targeting mismatched HLA-DPB1 for relapsed leukemia after allogeneic transplantation.

Relapsed leukemia after allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains a significant challenge, with the re-emergence of the primary disease being the most frequent cause of death. Human leukocyte antigen (HLA)-DPB1 mismatch occurs in approximately 70% of unrelated allo-HSCT cases, and targeting mismatched HLA-DPB1 is considered reasonable for treating relapsed leukemia following allo-HSCT if performed under proper conditions. In this study, we established several clones restricted to HLA-DPB1*02:01, -DPB1*04:02, and -DPB1*09:01 from three patients who underwent HLA-DPB1 mismatched allo-HSCT using donor-derived alloreactive T cells primed to mismatched HLA-DPB1 in the recipient's body after transplantation. A detailed analysis of the DPB1*09:01-restricted clone 2A9 showed reactivity against various leukemia cell lines and primary myeloid leukemia blasts, even with low HLA-DP expression. T cell receptor (TCR)-T cells derived from clone 2A9 retained the ability to trigger HLA-DPB1*09:01-restricted recognition and lysis of various leukemia cell lines in vitro. Our study demonstrated that the induction of mismatched HLA-DPB1 specific T cell clones from physiologically primed post-allo-HSCT alloreactive CD4+ T cells and the redirection of T cells with cloned TCR cDNA by gene transfer are feasible as techniques for future adoptive immunotherapy.

A simple method to distinguish residual elotuzumab from monoclonal paraprotein in immunofixation assays for multiple myeloma patients.

Negative immunofixation electrophoresis (IFE) of serum and/or urine is a diagnostic marker for determining a complete response (CR) after immunotherapy for multiple myeloma (MM). However, residual therapeutic antibodies such as elotuzumab (IgG-κ), can compromise IFE evaluation when the affected immunoglobulins belong to the same IgG-κ subclass. We thus sought to develop a simple and rapid method to treat patient serum before IFE to distinguish the residual elotuzumab. Serum samples from patients receiving elotuzumab were treated with a predetermined amount of soluble signaling lymphocyte activation molecule F7 (SLAMF7) protein and then subjected to conventional IFE testing. We tested our method in samples from 12 patients. The IgG-κ band in IFE disappeared or shifted after elotuzumab treatment in four patients with no bone marrow minimal residual disease and normalized free light chain, whereas seven patients with any sign of residual MM showed a remaining IgG-κ band after treatment. One-hour incubation of samples with 6-9 molar excess soluble SLAMF7 before IFE was sufficient to distinguish residual elotuzumab in 11 of 12 samples. This simple method does not require special reagents, can be performed in most clinical laboratories, and enables differentiation between patients with a CR and those requiring further treatment.

TCR-Like CAR-T Cells Targeting MHC-Bound Minor Histocompatibility Antigens.

Minor histocompatibility antigens (mHAgs) in allogeneic hematopoietic stem cell transplantation are highly immunogenic as they are foreign antigens and cause polymorphism between donors and recipients. Adoptive cell therapy with mHAg-specific T cells may be an effective option for therapy against recurring hematological malignancies following transplantation. Genetically modified T cells with T cell receptors (TCRs) specific to mHAgs have been developed, but formation of mispaired chimeric TCRs between endogenous and exogenous TCR chains may compromise their function. An alternative approach is the development of chimeric antigen receptor (CAR)-T cells with TCR-like specificity whose CAR transmembrane and intracellular domains do not compete with endogenous TCR for CD3 complexes and transmit their own activation signals. However, it has been shown that the recognition of low-density antigens by high-affinity CAR-T cells has poor sensitivity and specificity. This mini review focuses on the potential for and limitations of TCR-like CAR-T cells in targeting human leukocyte antigen-bound peptide antigens, based on their recognition mechanisms and their application in targeting mHAgs.

[Progress in immune checkpoint inhibitor therapies].

It has been eight years since the first immune checkpoint-blocking antibody, ipilimumab, was approved for metastatic malignant melanoma treatment by FDA in 2011. During this period, several other immune checkpoint blockers have been newly developed and approved for certain cancers, including malignant melanoma. However, there have been several concerns with some of these. The overall response rate did not exceed 30% in many cancers; although combination therapy with ipilimumab and nivolumab increased efficacy, immune-related adverse events also increased. This observation facilitated the reverse translational research (rTR) approach, using clinical specimens from treated patients to gradually elucidate the mechanism of resistance and biomarkers to select patients who can potentially benefit from immunotherapy. This has also promoted the development of novel combination therapies. In this review, immunological findings that highlight the resistance mechanisms of cancers against immune checkpoint blockers and the novel attempts to achieve a break-through will be discussed.

Frequent structural variations involving programmed death ligands in Epstein-Barr virus-associated lymphomas.

Viral infection induces potent cellular immunity and activated intracellular signaling, which may dictate the driver events involved in immune escape and clonal selection of virus-associated cancers, including Epstein-Barr virus (EBV)-positive lymphomas. Here, we thoroughly interrogated PD-L1/PD-L2-involving somatic aberrations in 384 samples from various lymphoma subtypes using high-throughput sequencing, particularly focusing on virus-associated lymphomas. A high frequency of PD-L1/PD-L2-involving genetic aberrations was observed in EBV-positive lymphomas [33 (22%) of 148 cases], including extranodal NK/T-cell lymphoma (ENKTL, 23%), aggressive NK-cell leukemia (57%), systemic EBV-positive T-cell lymphoproliferative disorder (17%) as well as EBV-positive diffuse large B-cell lymphoma (DLBCL, 19%) and peripheral T-cell lymphoma-not otherwise specified (15%). Predominantly causing a truncation of the 3'-untranslated region, these alterations represented the most prevalent somatic lesions in ENKTL. By contrast, the frequency was much lower in EBV-negative lymphomas regardless of histology type [12 (5%) of 236 cases]. Besides PD-L1/PD-L2 alterations, EBV-positive DLBCL exhibited a genetic profile distinct from EBV-negative one, characterized by frequent TET2 and DNMT3A mutations and the paucity of CD79B, MYD88, CDKN2A, and FAS alterations. Our findings illustrate unique genetic features of EBV-associated lymphomas, also suggesting a potential role of detecting PD-L1/PD-L2-involving lesions for these lymphomas to be effectively targeted by immune checkpoint blockade.

Improving TCR affinity on 293T cells.

This study presents an efficient method to improve TCR affinity, comprising 1) CDR-directed saturation mutation of TCR cDNA, 2) transient TCR display on CD3-expressing HEK293T (CD3-293T) cells by simple plasmid transfection, 3) staining with HLA-tetramers, and 4) multi-round sorting of cells with CD8-independent tetramer binding on a flow cytometer. Using these procedures, we successfully identified mutant TCRs with enhanced binding from an HLA-A*24:02-restricted, human telomerase reverse transcriptase (hTERT)-specific TCR. Two such clones, 2A7A and 2D162, harboring mutations in CDR1 and CDR2 of TCRß, respectively, were isolated with both showing sequential four amino acid substitutions. When expressed on CD3-293T cells along with wild-type TCRα, the TCR molecules of these mutants as well as their combinatory mutation, bound to HLA-A24/hTERT-tetramers more strongly than the wild-type TCRs, without binding to control tetramers. Besides, in order to facilitate a functional study of TCR, we established an artificial T cell line, designated as CD8I-J2, which expresses a human CD8 and IFN-γ producing cassette by modifying Jurkat-derived J.RT3-T3.5 cells. CD8I-J2 cells expressing wild-type or affinity-enhanced hTERT-specific TCRs were analyzed for their recognition of serially diluted cognate peptide on HLA-A*24:02-transduced T2 cells. CD8I-J2 cells expressing each mutant TCR recognized the hTERT peptide at lower concentrations than wild-type TCR. The hierarchy of peptide recognition is concordant with tetramer binding on CD3-293T cells and none of these mutant TCRs were cross-reactive with irrelevant peptides reported to be present on HLA-A*24:02 molecules as far as tested. These methods might thus be useful for obtaining high affinity mutants from other TCRs of interest.

Comparison of the tube test and column agglutination techniques for anti-A/-B antibody titration in healthy individuals.

BACKGROUND AND OBJECTIVES: Determination of the anti-A/-B titre pre- and post-transplantation is beneficial for treatment selection. Currently, the recommended method for antibody titration is the tube test (TT) assay. Dithiothreitol (DTT) is used for IgM antibody inactivation. Recently, a fully automated antibody titration assay using the column agglutination technique (CAT) was developed (auto-CAT). Our aim was to compare the auto-CAT and TT techniques for ABO antibody titration, to evaluate the effectiveness of DTT-treated plasma for use with auto-CAT and to define the cut-off value for antibody titration by auto-CAT. MATERIALS AND METHODS: We enrolled 30 healthy individuals, including 10 each for blood types A, B and O. We performed antibody titre measurement using the TT technique and auto-CAT simultaneously. Auto-CAT uses the bead column agglutination technology. RESULTS: With the auto-CAT cut-off value set to weak (w)+ with DTT treatment plasma, the concordance rate was 45%, and the weighted kappa value between TT and auto-CAT results was 0·994 in all subjects. Furthermore, there was a significant positive correlation between the anti-A/-B titre results obtained using the TT technique and auto-CAT in all blood types. Moreover, a positive bias (falsely elevated end-points due to agglomeration of A/B cells) was not observed in auto-CAT testing using DTT-treated plasma. CONCLUSION: Our results show that 1+ agglutination using the TT technique is equivalent to w+ agglutination obtained using auto-CAT. We recommend that DTT may be used with auto-CAT to measure antibody titres. Thus, we suggest that auto-CAT is useful for antibody titration in routine examination.

Antitumor activity of CAR-T cells targeting the intracellular oncoprotein WT1 can be enhanced by vaccination.

The recent success of chimeric antigen receptor (CAR)-T cell therapy for treatment of hematologic malignancies supports further development of treatments for both liquid and solid tumors. However, expansion of CAR-T cell therapy is limited by the availability of surface antigens specific for the tumor while sparing normal cells. There is a rich diversity of tumor antigens from intracellularly expressed proteins that current and conventional CAR-T cells are unable to target. Furthermore, adoptively transferred T cells often suffer from exhaustion and insufficient expansion, in part, because of the immunosuppressive mechanisms operating in tumor-bearing hosts. Therefore, it is necessary to develop means to further activate and expand those CAR-T cells in vivo. The Wilms tumor 1 (WT1) is an intracellular oncogenic transcription factor that is an attractive target for cancer immunotherapy because of its overexpression in a wide range of leukemias and solid tumors, and a low level of expression in normal adult tissues. In the present study, we developed CAR-T cells consisting of a single chain variable fragment (scFv) specific to the WT1235-243/HLA-A*2402 complex. The therapeutic efficacy of our CAR-T cells was demonstrated in a xenograft model, which was further enhanced by vaccination with dendritic cells (DCs) loaded with the corresponding antigen. This enhanced efficacy was mediated, at least partly, by the expansion and activation of CAR-T cells. CAR-T cells shown in the present study not only demonstrate the potential to expand the range of targets available to CAR-T cells, but also provide a proof of concept that efficacy of CAR-T cells targeting peptide/major histocompatibility complex can be boosted by vaccination.

Hematopoiesis by iPSC-derived hematopoietic stem cells of aplastic anemia that escape cytotoxic T-cell attack.

Hematopoietic stem cells (HSCs) that lack HLA-class I alleles as a result of copy-number neutral loss of heterozygosity of the short arm of chromosome 6 (6pLOH) or HLA allelic mutations often constitute hematopoiesis in patients with acquired aplastic anemia (AA), but the precise mechanisms underlying clonal hematopoiesis induced by these HLA-lacking (HLA-) HSCs remain unknown. To address this issue, we generated induced pluripotent stem cells (iPSCs) from an AA patient who possessed HLA-B4002-lacking (B4002-) leukocytes. Three different iPSC clones (wild-type [WT], 6pLOH+, and B*40:02-mutant) were established from the patient's monocytes. Three-week cultures of the iPSCs in the presence of various growth factors produced hematopoietic cells that make up 50% to 70% of the CD34+ cells of each phenotype. When 106 iPSC-derived CD34+ (iCD34+) cells with the 3 different genotypes were injected into the femoral bone of C57BL/6.Rag2 mice, 2.1% to 7.3% human multilineage CD45+ cells of each HLA phenotype were detected in the bone marrow, spleen, and peripheral blood of the mice at 9 to 12 weeks after the injection, with no significant difference in the human:mouse chimerism ratio among the 3 groups. Stimulation of the patient's CD8+ T cells with the WT iCD34+ cells generated a cytotoxic T lymphocyte (CTL) line capable of killing WT iCD34+ cells but not B4002- iCD34+ cells. These data suggest that B4002- iCD34+ cells show a repopulating ability similar to that of WT iCD34+ cells when autologous T cells are absent and CTL precursors capable of selectively killing WT HSCs are present in the patient's peripheral blood.

Rearrangement of VPS13B, a causative gene of Cohen syndrome, in a case of RUNX1-RUNX1T1 leukemia with t(8;12;21).

Variant chromosomal translocations associated with t(8;21) are observed in 3-4% of acute myeloid leukemia (AML) cases with a RUNX1-RUNX1T1 fusion gene. However, the molecular events that occur in variants of t(8;21) are not well characterized. In the present study, we report genetic features of a variant three-way translocation of t(8;12;21)(q22;p11;q22) in a patient with AML. In this patient, leukemia cells lacked azurophilic granules, which does not correspond with the classic features of t(8;21). RNA-seq analysis revealed that TM7SF3 at 12p11 was fused to VPS13B at 8q22 and VPS13B to RUNX1, in addition to RUNX1-RUNX1T1. VPS13B was located near RUNX1T1 and both were localized at the same chromosomal bands. The reading frames of TM7SF3 and VPS13B did not match to those of VPS13B and RUNX1, respectively. Disruption of VPS13B causes Cohen syndrome, which presents intermittent neutropenia with a left-shifted granulopoiesis in the bone marrow. Disruption of VPS13B may thus cause the unusual features of RUNX1-RUNX1T1 leukemia. Our case indicates that rearrangement of VPS13B may be additional genetic events in variant t(8;21).

Safety and persistence of WT1-specific T-cell receptor gene-transduced lymphocytes in patients with AML and MDS.

Wilms' tumor 1 (WT1) is constantly expressed in leukemic cells of acute leukemia and myelodysplastic syndrome (MDS). A T-cell receptor (TCR) that specifically reacts with WT1 peptide in the context of HLA-A*24:02 has been identified. We conducted a first-in-human trial of TCR-gene transduced T-cell (TCR-T-cell) transfer in patients with refractory acute myeloblastic leukemia (AML) and high-risk MDS to investigate the safety and cell kinetics of the T cells. The WT1-specific TCR-gene was transduced to T cells using a retroviral vector encoding small interfering RNAs for endogenous TCR genes. The T cells were transferred twice with a 4-week interval in a dose-escalating design. After the second transfer, sequential WT1 peptide vaccines were given. Eight patients, divided into 2 dose cohorts, received cell transfer. No adverse events of normal tissue were seen. The TCR-T cells were detected in peripheral blood for 8 weeks at levels proportional to the dose administered, and in 5 patients, they persisted throughout the study period. The persisting cells maintained ex vivo peptide-specific immune reactivity. Two patients showed transient decreases in blast counts in bone marrow, which was associated with recovery of hematopoiesis. Four of 5 patients who had persistent T cells at the end of the study survived more than 12 months. These results suggest WT1-specific TCR-T cells manipulated by ex vivo culture of polyclonal peripheral lymphocytes survived in vivo and retained the capacity to mount an immune reaction to WT1. This trial was registered at www.umin.ac.jp as #UMIN000011519.

The prognostic significance of EBV DNA load and EBER status in diagnostic specimens from diffuse large B-cell lymphoma patients.

Epstein-Barr virus (EBV)-encoded small RNA in situ hybridization (EBER-ISH) is a widely accepted method to evaluate EBV involvement in diffuse large B-cell lymphoma (DLBCL), although little is known regarding associations between EBV DNA load and the EBER status and whether EBV DNA load data provide additional clinical information. In this study, we quantified EBV DNA load in diagnostic specimens from DLBCL patients diagnosed at our hospital to evaluate clinical implications of EBV DNA load in diagnostic specimens as contrasted with EBER-ISH. Among 140 DLBCL patients without underlying immunodeficiency, 51 were evaluable for both EBER and EBV DNA load, 83 for EBER only and one for EBV DNA load only. The median EBV DNA load was 708 copies/µg. Although EBV DNA load was significantly higher for EBER-positive patients than for EBER-negative patients (p < 0.001), EBV DNA was detected in up to 72% of EBER-negative patients. Progression-free survival and overall survival were significantly worse for patients with EBV DNA load above 700 copies/µg than for those with EBV DNA load below 700 copies/µg (p = 0.009 and p = 0.003); they were also significantly worse for EBER-positive patients than for EBER-negative patients (p < 0.001 and p = 0.001). Even among EBER-negative patients, higher EBV DNA load conferred worse progression-free survival and overall survival (p = 0.041 and p = 0.013). These findings indicate that EBV DNA load in diagnostic specimens is not a simple surrogate for the EBER status and may be a potential biomarker associated with EBV involvement and prognosis in DLBCL. Copyright © 2015 John Wiley & Sons, Ltd.

Successful treatment with allogeneic stem cell transplantation followed by DLI and TKIs for e6a2 BCR-ABL-positive acute myeloid leukaemia: A case report and literature review.

RATIONALE: Patients with the e6a2 BCR-ABL transcript, 1 of the atypical transcripts, have been reported to have a poor prognosis, and allogeneic stem cell transplantation (ASCT) can be considered as additional therapy. However, long-term survival after ASCT for this disease is rare. PATIENT CONCERNS: This report concerns a 55-year-old female patient with e6a2 BCR-ABL-positive acute myeloid leukemia including the outcome of ASCT followed by donor lymphocyte infusion (DLI). DIAGNOSES: The breakpoint was confirmed by direct sequencing. Her minimal residual disease could be detected by nested reverse-transcription polymerase chain reaction using primers for the minor BCR-ABL (e1a2) transcript. INTERVENTIONS: Treatment with tyrosine kinase inhibitors (TKIs) and ASCT followed by DLI. OUTCOMES: Despite multiple cytogenetic and molecular relapses after ASCT, she remains in molecular remission at 46 months after ASCT. LESSONS: This case indicates the efficacy of the combination of the graft-versus-leukemia effect and TKIs for e6a2 BCR-ABL-positive acute leukemia. When the Philadelphia chromosome with an unusual chromosomal breakpoint is suggested, we should clarify the breakpoint because that information can aid molecular assessments and decisions to provide an additional or alternative therapy.

Historical perspectives and future directions of gene-modified T-cell therapy.

Adoptive immunotherapy using genetically modified T-cells is an emerging and promising treatment modality for various malignant diseases. The technology involves engineering of T-cells armed with well-characterized receptors such as T-cell receptors or chimeric antigen receptors. The latter is comprised of antibody/ligand and intracellular signaling domains. These molecules can be further modified to enhance their affinity, specificity, and several other functions. The success of adoptive immunotherapy is rooted in the application of extensive insights derived from allogeneic hematopoietic stem cell transplantations (HSCT). Herein, the historical perspectives of gene-modified T-cell therapy are discussed by comparison with the evolution of allogeneic HSCT. Furthermore, the prospects for the development and improvement of these powerful therapeutic methods are also highlighted.

Aberrant PD-L1 expression through 3'-UTR disruption in multiple cancers.

Successful treatment of many patients with advanced cancer using antibodies against programmed cell death 1 (PD-1; also known as PDCD1) and its ligand (PD-L1; also known as CD274) has highlighted the critical importance of PD-1/PD-L1-mediated immune escape in cancer development. However, the genetic basis for the immune escape has not been fully elucidated, with the exception of elevated PD-L1 expression by gene amplification and utilization of an ectopic promoter by translocation, as reported in Hodgkin and other B-cell lymphomas, as well as stomach adenocarcinoma. Here we show a unique genetic mechanism of immune escape caused by structural variations (SVs) commonly disrupting the 3' region of the PD-L1 gene. Widely affecting multiple common human cancer types, including adult T-cell leukaemia/lymphoma (27%), diffuse large B-cell lymphoma (8%), and stomach adenocarcinoma (2%), these SVs invariably lead to a marked elevation of aberrant PD-L1 transcripts that are stabilized by truncation of the 3'-untranslated region (UTR). Disruption of the Pd-l1 3'-UTR in mice enables immune evasion of EG7-OVA tumour cells with elevated Pd-l1 expression in vivo, which is effectively inhibited by Pd-1/Pd-l1 blockade, supporting the role of relevant SVs in clonal selection through immune evasion. Our findings not only unmask a novel regulatory mechanism of PD-L1 expression, but also suggest that PD-L1 3'-UTR disruption could serve as a genetic marker to identify cancers that actively evade anti-tumour immunity through PD-L1 overexpression.

Prognostic significance of Wilms tumor 1 mRNA expression levels in peripheral blood and bone marrow in patients with myelodysplastic syndromes.

BACKGROUND: This present study was designed to follow up 82 patients among 115 MDS patients registered in study ODK-0801 for 5 years, to analyze the relationship between the WT1 mRNA expression level and prognosis. OBJECTIVE: This study aimed to investigate the clinical utility of WT1 mRNA expression levels. METHODS: After study ODK-0801, we investigated the conditions of the same patients once a year, including any clinical and laboratory findings supporting the diagnosis, and treatment among the living patients. RESULTS: When we assessed the survival time of 82 MDS patients by WT1 mRNA expression level, there were significant differences between the < 500 and ≥ 104 copies/µ g RNA groups and between the 500-104 and ≥ 104 copies/µ g RNA groups for BM levels (p < 0.01). Examination of the time of freedom from acute myeloid eukemia (AML) transformation indicated that a high WT1 mRNA expression level (> 104 copies/µ g RNA) was a strong prognostic factor for a short time to AML transformation. CONCLUSION: The results indicate that the tumorigenesis of MDS is likely to originate at the stem cell level, suggesting that the WT1 mRNA level measurement in the BM is an effective prognostic marker in patients with MDS.

TP53 mutations in older adults with acute myeloid leukemia.

The net benefits of induction therapy for older adults with acute myeloid leukemia (AML) remain controversial. Because AML in older adults is a heterogeneous disease, it is important to identify those who are unlikely to benefit from induction therapy based on information available at the initial assessment. We used next-generation sequencing to analyze TP53 mutation status in AML patients aged 60 years or older, and evaluated its effects on outcomes. TP53 mutations were detected in 12 of 77 patients (16 %), and there was a significant association between TP53 mutations and monosomal karyotype. Patients with TP53 mutations had significantly worse survival than those without (P = 0.009), and multivariate analysis identified TP53 mutation status as the most significant prognostic factor for survival. Neverthelsess, TP53-mutated patients had a 42 % chance of complete remission and a median survival of 8.0 months, which compares favorably with those who did not undergo induction therapy, even in the short term. These results suggest that screening for TP53 mutations at diagnosis is useful for identifying older adults with AML who are least likely to respond to chemotherapy, although the presence of this mutation alone does not seem to justify rejecting induction therapy.