Gene panel test, which has been used in the field of solid tumors, is expected to be introduced in the field of hematopoietic tumors in the near future. Unintended germline variants may be detected ...due to the comprehensive nature of the gene panel test, and these are called "secondary findings." Additionally, it sometimes reveals that a person has germline variants that predispose the carriers to develop the disease. There are several impeding issues to be addressed regarding these germline variants, including detection methods, obtaining informed consent, scope of variants to be disclosed, and genetic counseling methods. In the field of hematopoietic tumors, the problem is further complicated by the possibility of detecting germline variants in donors because allogeneic hematopoietic stem cell transplantation constitutes an important treatment modality in this field. Thus, this paper aims to outline the issues related to germline variants in gene panel tests, which were discussed at the symposium "NGS-based multi-gene panel testing in hematology/oncology" at the annual meeting of the Japanese Society of Hematology in 2021.
Voriconazole therapeutic drug monitoring (TDM) is increasingly used in clinical practice. However, the utility of voriconazole TDM to guide therapy remains uncertain and controversial. We conducted a ...meta-analysis of studies assessing the relationship between voriconazole serum concentration and clinical outcomes of success and toxicity.
We searched bibliographic databases for studies on voriconazole serum concentrations and clinical outcomes. We compared success outcomes between patients with therapeutic and subtherapeutic voriconazole serum concentrations, and toxicity outcomes between patients with and without supratherapeutic serum concentrations.
Twenty-four studies were analysed. Pooled analysis for efficacy endpoint demonstrated that patients with therapeutic voriconazole serum concentrations (1.0-2.2 mg/L) were more likely to have successful outcomes compared with those with subtherapeutic voriconazole serum concentrations (OR 2.30; 95% CI 1.39-3.81). A therapeutic threshold of 1.0 mg/L was most predictive of successful outcome (OR 1.94; 95% CI 1.04-3.62). Patients with therapeutic concentrations did not have better survival rates. Pooled analysis for toxicity endpoint demonstrated that patients with supratherapeutic voriconazole serum concentrations (4.0-6.0 mg/L) were at increased risk of toxicity (OR 4.17; 95% CI 2.08-8.36). A supratherapeutic threshold of 6.0 mg/L was most predictive of toxicity (OR 4.60; 95% CI 1.49-14.16).
Patients with therapeutic voriconazole serum concentrations were twice as likely to achieve successful outcomes. The likelihood of toxicity associated with supratherapeutic voriconazole serum concentrations was 4-fold that of therapeutic concentrations. Our findings suggest that the use of voriconazole TDM to aim for serum concentrations between 1.0 and 6.0 mg/L during therapy may be warranted to optimize clinical success and minimize toxicity.
Transfer RNA-derived fragments (tRFs) are emerging small noncoding RNAs that, although commonly altered in cancer, have poorly defined roles in tumorigenesis
. Here we show that pseudouridylation (Ψ) ...of a stem cell-enriched tRF subtype
, mini tRFs containing a 5' terminal oligoguanine (mTOG), selectively inhibits aberrant protein synthesis programmes, thereby promoting engraftment and differentiation of haematopoietic stem and progenitor cells (HSPCs) in patients with myelodysplastic syndrome (MDS). Building on evidence that mTOG-Ψ targets polyadenylate-binding protein cytoplasmic 1 (PABPC1), we employed isotope exchange proteomics to reveal critical interactions between mTOG and functional RNA-recognition motif (RRM) domains of PABPC1. Mechanistically, this hinders the recruitment of translational co-activator PABPC1-interacting protein 1 (PAIP1)
and strongly represses the translation of transcripts sharing pyrimidine-enriched sequences (PES) at the 5' untranslated region (UTR), including 5' terminal oligopyrimidine tracts (TOP) that encode protein machinery components and are frequently altered in cancer
. Significantly, mTOG dysregulation leads to aberrantly increased translation of 5' PES messenger RNA (mRNA) in malignant MDS-HSPCs and is clinically associated with leukaemic transformation and reduced patient survival. These findings define a critical role for tRFs and Ψ in difficult-to-treat subsets of MDS characterized by high risk of progression to acute myeloid leukaemia (AML).
Clonal hematopoiesis (CH) in apparently healthy individuals is implicated in the development of hematological malignancies (HM) and cardiovascular diseases. Previous studies of CH analyzed either ...single-nucleotide variants and indels (SNVs/indels) or copy number alterations (CNAs), but not both. Here, using a combination of targeted sequencing of 23 CH-related genes and array-based CNA detection of blood-derived DNA, we have delineated the landscape of CH-related SNVs/indels and CNAs in 11,234 individuals without HM from the BioBank Japan cohort, including 672 individuals with subsequent HM development, and studied the effects of these somatic alterations on mortality from HM and cardiovascular disease, as well as on hematological and cardiovascular phenotypes. The total number of both types of CH-related lesions and their clone size positively correlated with blood count abnormalities and mortality from HM. CH-related SNVs/indels and CNAs exhibited statistically significant co-occurrence in the same individuals. In particular, co-occurrence of SNVs/indels and CNAs affecting DNMT3A, TET2, JAK2 and TP53 resulted in biallelic alterations of these genes and was associated with higher HM mortality. Co-occurrence of SNVs/indels and CNAs also modulated risks for cardiovascular mortality. These findings highlight the importance of detecting both SNVs/indels and CNAs in the evaluation of CH.
We investigated the role of Hoip, a catalytic subunit of linear ubiquitin chain assembly complex (LUBAC), in adult hematopoiesis and myeloid leukemia by using both conditional deletion of Hoip and ...small-molecule chemical inhibitors of Hoip. Conditional deletion of Hoip led to significantly longer survival and marked depletion of leukemia burden in murine myeloid leukemia models. Nevertheless, a competitive transplantation assay showed the reduction of donor-derived cells in the bone marrow of recipient mice was relatively mild after conditional deletion of Hoip. Although both Hoip-deficient hematopoietic stem cells (HSCs) and leukemia stem cells (LSCs) impaired the maintenance of quiescence, conditional deletion of Hoipinduced apoptosis in LSCs but not HSCs in vivo. Structure-function analysis revealed that LUBAC ligase activity and the interaction of LUBAC subunits were critical for the propagation of leukemia. Hoip regulated oxidative phosphorylation pathway independently of nuclear factor kappa B pathway in leukemia, but not in normal hematopoietic cells. Finally, the administration of thiolutin, which inhibits the catalytic activity of Hoip, improved the survival of recipients in murine myeloid leukemia and suppressed propagation in the patient-derived xenograft model of myeloid leukemia. Collectively, these data indicate that inhibition of LUBAC activity may be a valid therapeutic target for myeloid leukemia.
Although daily higher urinary sodium (Na) and potassium (K) excretion ratio is associated with the risk of cardiovascular disease in the general population, a low Na/K ratio is associated with renal ...dysfunction in critically ill patients. Thus, we retrospectively analyzed the impact of daily urinary Na and K excretion and their ratio on non-relapse mortality (NRM) and overall mortality in 172 adult single-unit cord blood transplantation (CBT) patients treated at our institution between 2007 and 2020. Multivariate analysis showed that a low urinary Na/K ratio at both 14 days (hazard ratio HR, 4.82; 95% confidence interval CI, 1.81-12.83; P = 0.001) and 28 days (HR, 4.47; 95% CI 1.32-15.12; P = 0.015) was significantly associated with higher NRM. Furthermore, a low urinary Na/K ratio at 28 days was significantly associated with higher overall mortality (HR, 2.38; 95% CI 1.15-4.91; P = 0.018). Patients with a low urinary Na/K ratio had decreased urine volume, more weight gain, experienced more grade III-IV acute graft-versus-host disease, and required corticosteroids by 28 days after CBT. These findings indicate that a low urinary Na/K ratio early after single-unit CBT is associated with poor NRM and survival in adults.
Splicing factor mutations are characteristic of myelodysplastic syndromes (MDS) and related myeloid neoplasms and implicated in their pathogenesis, but their roles in the development of MDS have not ...been fully elucidated. In the present study, we investigated the consequence of mutant Srsf2 expression using newly generated Vav1-Cre–mediated conditional knockin mice. Mice carrying a heterozygous Srsf2 P95H mutation showed significantly reduced numbers of hematopoietic stem and progenitor cells (HSPCs) and differentiation defects both in the steady-state condition and transplantation settings. Srsf2-mutated hematopoietic stem cells (HSCs) showed impaired long-term reconstitution compared with control mice in competitive repopulation assays. Although the Srsf2 mutant mice did not develop MDS under the steady-state condition, when their stem cells were transplanted into lethally irradiated mice, the recipients developed anemia, leukopenia, and erythroid dysplasia, which suggests the role of replicative stress in the development of an MDS-like phenotype in Srsf2-mutated mice. RNA sequencing of the Srsf2-mutated HSPCs revealed a number of abnormal splicing events and differentially expressed genes, including several potential targets implicated in the pathogenesis of hematopoietic malignancies, such as Csf3r, Fyn, Gnas, Nsd1, Hnrnpa2b1, and Trp53bp1. Among the mutant Srsf2-associated splicing events, most commonly observed were the enhanced inclusion and/or exclusion of cassette exons, which were caused by the altered consensus motifs for the recognition of exonic splicing enhancers. Our findings suggest that the mutant Srsf2 leads to a compromised HSC function by causing abnormal RNA splicing and expression, contributing to the deregulated hematopoiesis that recapitulates the MDS phenotypes, possibly as a result of additional genetic and/or environmental insults.
•Blood-specific expression of the Srsf2 P95H mutant results in decreased stem/progenitor cell numbers and a reduced repopulation capacity.•Srsf2 P95H mutation by itself is not sufficient to develop MDS but contributes to the MDS phenotype in transplantation settings.
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Germline
DDX41
mutations were recently reported to cause MDS/AML and donor-derived leukemia after transplantation. While previously described in Western countries,
DDX41
variants have not been ...reported in a Southeast Asian population. We performed targeted sequencing of blood or bone marrow samples from 109 Thai patients with myeloid malignancies. Among the 109 patients (75 MDS, 8 MPN, 11 MDS/MPN and 15 AML), the most frequent mutations were in
ASXL1
(17.4%),
TET2
(16.5%) and
SRSF2
(12.8%), respectively.
DDX41
variants were detectable in six (5.5%) cases. Four patients exhibited three presumable germline
DDX41
mutations: p.S21fs (
n
= 2), p.F235fs (
n
= 1), and p.R339H (
n
= 1). While p.S21fs was previously reported in myeloid neoplasm, the latter two variants have not been described. Two of these cases harbored concomitant probable germline/somatic
DDX41
mutations (p.S21fs/p.R525H and p.R339H/p.K494T), while the other two patients carried only somatic mutations (p.R525H and p.F438L). The p.K494T and p.F438L variants have not been previously reported. In patients with
DDX41
alterations, the diagnoses were MDS with excess blasts (4), secondary AML (1) and low-risk MDS (1). In conclusion, we identified
DDX41
variants in Thai patients with myeloid malignancies in which these variants could be used to assess predisposition to MDS in Southeast Asia.
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