Panel‑based next‑generation sequencing facilitates the characterization of childhood acute myeloid leukemia in clinical settings

Acute myeloid leukemia (AML) accounts for ~20% of pediatric leukemia cases. The prognosis of pediatric AML has been improved in recent decades, but it trails that of most other types of pediatric cancer, with mortality rates of 30‑40%. Consequently, newer more targeted drugs are required for incorporation into treatment plans. These newer drugs selectively target AML cells with specific gene alterations. However, there are significant differences in genetic alterations between adult and pediatric patients with AML. In the present study, inexpensive and rapid next‑generation sequencing (NGS) of >150 cancer‑related genes was performed for matched diagnostic, remission and relapse (if any) samples from 27 pediatric patients with AML. In this analysis, seven genes were recurrently mutated. KRAS was mutated in seven patients, NRAS was mutated in three patients, and KIT, GATA1, WT1, PTPN11, JAK3 and FLT3 were each mutated in two patients. Among patients with relapsed AML, six harbored KRAS mutations at diagnosis; however, four of these patients lost these mutations at relapse. Additionally, two genetic alterations (FLT3‑ITD and TP53 alterations) were detected among patients who eventually relapsed, and these mutations are reported to be adverse prognostic factors for adult patients with AML. This panel‑based, targeted sequencing approach may be useful in determining the genetic background of pediatric AML and improving the prediction of treatment response and detection of potentially targetable gene alterations. RAS pathway mutations were highly unstable at relapse; therefore, these mutations should be chosen as a target with caution. Incorporating this panel‑based NGS approach into the clinical setting may allow for a patient‑oriented strategy of precision treatment for childhood AML

Aberrant splicing of U12-type introns is the hallmark of ZRSR2 mutant myelodysplastic syndrome.

Somatic mutations in the spliceosome gene ZRSR2-located on the X chromosome-are associated with myelodysplastic syndrome (MDS). ZRSR2 is involved in the recognition of 3'-splice site during the early stages of spliceosome assembly; however, its precise role in RNA splicing has remained unclear. Here we characterize ZRSR2 as an essential component of the minor spliceosome (U12 dependent) assembly. shRNA-mediated knockdown of ZRSR2 leads to impaired splicing of the U12-type introns and RNA-sequencing of MDS bone marrow reveals that loss of ZRSR2 activity causes increased mis-splicing. These splicing defects involve retention of the U12-type introns, while splicing of the U2-type introns remain mostly unaffected. ZRSR2-deficient cells also exhibit reduced proliferation potential and distinct alterations in myeloid and erythroid differentiation in vitro. These data identify a specific role for ZRSR2 in RNA splicing and highlight dysregulated splicing of U12-type introns as a characteristic feature of ZRSR2 mutations in MDS

Notable underlying mechanism for pancreatic β-cell dysfunction and atherosclerosis: Pleiotropic roles of incretin and insulin signaling

Under healthy conditions, pancreatic β-cells produce and secrete the insulin hormone in response to blood glucose levels. Under diabetic conditions, however, β-cells are compelled to continuously secrete larger amounts of insulin to reduce blood glucose levels, and thereby, the β-cell function is debilitated in the long run. In the diabetic state, expression levels of insulin gene transcription factors and incretin receptors are downregulated, which we think is closely associated with β-cell failure. These data also suggest that it would be better to use incretin-based drugs at an early stage of diabetes when incretin receptor expression is preserved. Indeed, it was shown that incretin-based drugs exerted more protective effects on β-cells at an early stage. Furthermore, it was shown recently that endothelial cell dysfunction was also associated with pancreatic β-cell dysfunction. After ablation of insulin signaling in endothelial cells, the β-cell function and mass were substantially reduced, which was also accompanied by reduced expression of insulin gene transcription factors and incretin receptors in β-cells. On the other hand, it has been drawing much attention that incretin plays a protective role against the development of atherosclerosis. Many basic and clinical data have underscored the importance of incretin in arteries. Furthermore, it was shown recently that incretin receptor expression was downregulated in arteries under diabetic conditions, which likely diminishes the protective effects of incretin against atherosclerosis. Furthermore, a series of large-scale clinical trials (SPAED-A, SPIKE, LEADER, SUSTAIN-6, REWIND, PIONEER trials) have shown that various incretin-related drugs have beneficial effects against atherosclerosis and subsequent cardiovascular events. These data strengthen the hypothesis that incretin plays an important role in the arteries of humans, as well as rodents.Kaneto, H.; Obata, A.; Kimura, T.; Shimoda, M.; Sanada, J.; Fushimi, Y.; Katakami, N.; Matsuoka, T.; Kaku, K. Notable Underlying Mechanism for Pancreatic β-Cell Dysfunction and Atherosclerosis: Pleiotropic Roles of Incretin and Insulin Signaling. Int. J. Mol. Sci. 2020, 21, 9444

Allelotypes of lung adenocarcinomas featuring ALK fusion demonstrate fewer onco- and suppressor gene changes

BACKGROUND: A subset of lung adenocarcinomas harboring an EML4-ALK fusion gene resulting in dominant oncogenic activity has emerged as a target for specific therapy. EML4-ALK fusion confers a characteristic histology and is detected more frequently in never or light smokers and younger patients. METHODS: To gain insights into etiology and carcinogenic mechanisms we conducted analyses to compare allelotypes of 35 ALK fusion-positive and 95 -negative tumours using single nucleotide polymorphism (SNP) arrays and especially designed software which enabled precise global genomic profiling. RESULTS: Overall aberration numbers (gains + losses) of chromosomal alterations were 8.42 and 9.56 in tumours with and without ALK fusion, respectively, the difference not being statistically significant, although patterns of gain and loss were distinct. Interestingly, among selected genomic regions, oncogene-related examples such as 1p34.3(MYCL1), 7q11.2(EGFR), 7p21.1, 8q24.21(MYC), 16p13.3, 17q12(ERBB2) and 17q25.1 showed significantly less gain. Also, changes in tumour suppressor gene-related regions, such as 9p21.3 (CDKN2A) 9p23-24.1 (PTPRD), 13q14.2 (RB1), were significantly fewer in tumours with ALK fusion. CONCLUSION: Global genomic comparison with SNP arrays showed tumours with ALK fusion to have fewer alterations in oncogenes and suppressor genes despite a similar overall aberration frequency, suggesting very strong oncogenic potency of ALK activation by gene fusion

ACTN1 Mutations Cause Congenital Macrothrombocytopenia

Congenital macrothrombocytopenia (CMTP) is a heterogeneous group of rare platelet disorders characterized by a congenital reduction of platelet counts and abnormally large platelets, for which CMTP-causing mutations are only found in approximately half the cases. We herein performed whole-exome sequencing and targeted Sanger sequencing to identify mutations that cause CMTP, in which a dominant mode of transmission had been suspected but for which no known responsible mutations have been documented. In 13 Japanese CMTP-affected pedigrees, we identified six (46%) affected by ACTN1 variants cosegregating with CMTP. In the entire cohort, ACNT1 variants accounted for 5.5% of the dominant forms of CMTP cases and represented the fourth most common cause in Japanese individuals. Individuals with ACTN1 variants presented with moderate macrothrombocytopenia with anisocytosis but were either asymptomatic or had only a modest bleeding tendency. ACTN1 encodes α-actinin-1, a member of the actin-crosslinking protein superfamily that participates in the organization of the cytoskeleton. In vitro transfection experiments in Chinese hamster ovary cells demonstrated that altered α-actinin-1 disrupted the normal actin-based cytoskeletal structure. Moreover, transduction of mouse fetal liver-derived megakaryocytes with disease-associated ACTN1 variants caused a disorganized actin-based cytoskeleton in megakaryocytes, resulting in the production of abnormally large proplatelet tips, which were reduced in number. Our findings provide an insight into the pathogenesis of CMTP

Incidence of endocrine-related immune-related adverse events in Japanese subjects with various types of cancer

BackgroundImmune checkpoint inhibitors (ICIs), such as cytotoxic T lymphocyte antigen-4 (CTLA-4) inhibitors, programmed cell death protein 1 (PD-1) inhibitors, and programmed cell death protein 1 ligand 1 (PD-L1) inhibitors, are often used to treat a variety of malignancies. ICIs are known to cause endocrine-related immune-related adverse events (irAEs), but the incidence varies among reports and/or agents. This study evaluated the incidence of endocrine-related irAEs in patients who were treated with ICIs in Japan.MethodThis single-center, retrospective, observational study examined the incidence and clinical characteristics of endocrine-related irAEs in 466 participants who were treated with ICIs at Kawasaki Medical School Hospital.ResultThe mean age of participants with and without endocrine-related irAEs was 69.1 ± 1.8 years and 68.1 ± 1.1 years, respectively, with no difference between them. The overall incidence of any endocrine-related irAEs among the participants was 25.5%. Hypothyroidism was prevalent in 24.3%, hypoadrenocorticism in 3.2%, hypopituitarism in 0.9%, and insulin-dependent diabetes mellitus in 1.1%. Participants receiving combination therapy with CTLA-4 and PD-1 inhibitors had a significantly higher incidence of endocrine-related irAEs than those receiving monotherapy.ConclusionEndocrine-related irAEs correlated significantly with survival and mean observation period. There was substantial difference in the incidence of endocrine-related irAEs among various types of ICIs and types of cancer. We should bear in mind that endocrine testing is necessary during the treatment with ICIs

Frequent loss of HLA alleles associated with copy number-neutral 6pLOH in acquired aplastic anemia

Idiopathic aplastic anemia (AA) is a common cause of acquired BM failure. Although autoimmunity to hematopoietic progenitors is thought to be responsible for its pathogenesis, little is known about the molecular basis of this autoimmunity. Here we show that a substantial proportion of AA patients harbor clonal hematopoiesis characterized by the presence of acquired copy number-neutral loss of heterozygosity (CNN-LOH) of the 6p arms (6pLOH). The 6pLOH commonly involved the HLA locus, leading to loss of one HLA haplotype. Loss of HLA-Aexpression from multiple lineages of leukocytes was confirmed by flow cytometry in all 6pLOH(+) cases. Surprisingly, the missing HLAalleles in 6pLOH(+) clones were conspicuously biased to particular alleles, including HLA-A*02:01, A*02:06, A*31:01, and B*40:02. A large-scale epidemiologic study on the HLA alleles of patients with various hematologic diseases revealed that the 4 HLA alleles were over-represented in the germline of AA patients. These findings indicate that the 6pLOH(+) hematopoiesis found in AA represents "escapes"hematopoiesis from the autoimmunity, which is mediated by cytotoxic T cells that target the relevant autoantigens presented on hematopoietic progenitors through these class I HLAs. Our results provide a novel insight into the genetic basis of the pathogenesis of AA. © 2011 by The American Society of Hematology

Clonal evolution and clinical implications of genetic abnormalities in blastic transformation of chronic myeloid leukaemia

Blast crisis (BC) predicts dismal outcomes in patients with chronic myeloid leukaemia (CML). Although additional genetic alterations play a central role in BC, the landscape and prognostic impact of these alterations remain elusive. Here, we comprehensively investigate genetic abnormalities in 136 BC and 148 chronic phase (CP) samples obtained from 216 CML patients using exome and targeted sequencing. One or more genetic abnormalities are found in 126 (92.6%) out of the 136 BC patients, including the RUNX1-ETS2 fusion and NBEAL2 mutations. The number of genetic alterations increase during the transition from CP to BC, which is markedly suppressed by tyrosine kinase inhibitors (TKIs). The lineage of the BC and prior use of TKIs correlate with distinct molecular profiles. Notably, genetic alterations, rather than clinical variables, contribute to a better prediction of BC prognosis. In conclusion, genetic abnormalities can help predict clinical outcomes and can guide clinical decisions in CML

骨髄系腫瘍における腫瘍抑制遺伝子C-CBLの機能獲得型変異

This paper was published in Nature 2009 Aug 13;460(7257):904-8. doi: 10.1038/nature08240. http://www.nature.com/nature/journal/v460/n7257/full/nature08240.html京都大学0048新制・論文博士博士(医学)乙第12855号論医博第2085号新制||医||1006(附属図書館)31535(主査)教授 髙折 晃史, 教授 羽賀 博典, 教授 岩井 一宏学位規則第4条第2項該当Doctor of Medical ScienceKyoto UniversityDFA