Cytokine profiling in 128 patients with transient abnormal myelopoiesis: a report from the JPLSG TAM-10 trial.

Transient abnormal myelopoiesis (TAM) occurs in 10% of neonates with Down syndrome (DS). Although most patients show spontaneous resolution of TAM, early death occurs in approximately 20% of cases. Therefore, new biomarkers are needed to predict early death and determine therapeutic interventions. This study aimed to determine the association between clinical characteristics and cytokine levels in patients with TAM. A total of 128 patients with DS with TAM enrolled in the TAM-10 study conducted by the Japanese Pediatric Leukemia/Lymphoma Study Group were included in this study. Five cytokine levels [interleukin (IL)-1b, IL-1 receptor agonist, IL-6, IL-8, and IL-13] were significantly higher in patients with early death than in those with non-early death. Cumulative incidence rates (CIR) of early death were significantly associated with high levels of the five cytokines. Based on unsupervised consensus clustering, patients were classified into three cytokine groups: hot-1 (n = 37), hot-2 (n = 42), and cold (n = 49). The CIR of early death was significantly different between the cytokine groups [hot-1/2 (n = 79); cold (n = 49); CIR (95% confidence interval [CI]) = 16.5% (7.9%-24.2%); 2.0% (0.0%-5.9%), P = 0.013]. Furthermore, cytokine groups (hot-1/2 vs. cold) were independent poor prognostic factors in the multivariable analysis for early death [hazard ratio (95% CI) = 19.25 (2.056-180.3), P = 0.010]. These results provide valuable information that cytokine level measurement was useful in predicting early death in patients with TAM and might help to determine the need for therapeutic interventions.

Landscape of driver mutations and their clinical effects on Down syndrome-related myeloid neoplasms.

Transient abnormal myelopoiesis (TAM) is a common complication in newborns with Down syndrome (DS). It commonly progresses to myeloid leukemia (ML-DS) after spontaneous regression. In contrast to the favorable prognosis of primary ML-DS, patients with refractory/relapsed ML-DS have poor outcomes. However, the molecular basis for refractoriness and relapse, and the full spectrum of driver mutations in ML-DS remain largely unknown. We conducted a genomic profiling study of 143 TAM, 204 ML-DS, and 34 non-DS acute megakaryoblastic leukemia cases, including 39 ML-DS cases analyzed by exome sequencing. Sixteen novel mutational targets were identified in ML-DS samples. Of these, inactivations of IRX1 (16.2%) and ZBTB7A (13.2%) were commonly implicated in the upregulation of the MYC pathway and were potential targets for ML-DS treatment with bromodomain-containing protein 4 inhibitors. Partial tandem duplications of RUNX1 on chromosome 21 were also found, specifically in ML-DS samples (13.7%), presenting its essential role in DS leukemia progression. Finally, in 177 patients with ML-DS treated following the same ML-DS protocol (the Japanese Pediatric Leukemia and Lymphoma Study Group AML-D05/D11), CDKN2A, TP53, ZBTB7A, and JAK2 alterations were associated with a poor prognosis. Patients with CDKN2A deletions (n = 7) or TP53 mutations (n = 4) had substantially lower 3-year event-free survival [28.6% vs. 90.5%, P < 0.001; 25.0% vs. 89.5%, P < 0.001] than those without these mutations. These findings considerably change the mutational landscape of ML-DS, provide new insights into the mechanisms of progression from TAM to ML-DS, and help identify new therapeutic targets and strategies for ML-DS.

Development and validation of a promising 5-gene prognostic model for pediatric acute myeloid leukemia.

Risk classification in pediatric acute myeloid leukemia (P-AML) is crucial for personalizing treatments. Thus, we aimed to establish a risk-stratification tool for P-AML patients and eventually guide individual treatment. A total of 256 P-AML patients with accredited mRNA-seq data from the TARGET database were divided into training and internal validation datasets. A gene-expression-based prognostic score was constructed for overall survival (OS), by using univariate Cox analysis, LASSO regression analysis, Kaplan-Meier (K-M) survival, and multivariate Cox analysis. A P-AML-5G prognostic score bioinformatically derived from expression levels of 5 genes (ZNF775, RNFT1, CRNDE, COL23A1, and TTC38), clustered P-AML patients in training dataset into high-risk group (above optimal cut-off) with shorter OS, and low-risk group (below optimal cut-off) with longer OS (p < 0.0001). Meanwhile, similar results were obtained in internal validation dataset (p = 0.005), combination dataset (p < 0.001), two treatment sub-groups (p < 0.05), intermediate-risk group defined with the Children's Oncology Group (COG) (p < 0.05) and an external Japanese P-AML dataset (p = 0.005). The model was further validated in the COG study AAML1031(p = 0.001), and based on transcriptomic analysis of 943 pediatric patients and 70 normal bone marrow samples from this dataset, two genes in the model demonstrated significant differential expression between the groups [all log2(foldchange) > 3, p < 0.001]. Independent of other prognostic factors, the P-AML-5G groups presented the highest concordance-index values in training dataset, chemo-therapy only treatment subgroups of the training and internal validation datasets, and whole genome-sequencing subgroup of the combined dataset, outperforming two Children's Oncology Group (COG) risk stratification systems, 2022 European LeukemiaNet (ELN) risk classification tool and two leukemic stem cell expression-based models. The 5-gene prognostic model generated by a single assay can further refine the current COG risk stratification system that relies on numerous tests and may have the potential for the risk judgment and identification of the high-risk pediatric AML patients receiving chemo-therapy only treatment.

High IL2RA/CD25 expression is a prognostic stem cell biomarker for pediatric acute myeloid leukemia without a core-binding factor.

CD25 is an aberrant marker expressed on the leukemic stem cell (LSC) surface and an immunotherapy target in acute myeloid leukemia (AML). However, the clinical prevalence and significance of CD25 expression in pediatric AML are unknown. High IL2RA/CD25 expression in pediatric AML showed a stem cell-like phenotype, and elevated CD25 expression was associated with lower overall survival (p < .001) and event-free survival (p < .001) in the Japanese Pediatric Leukemia/Lymphoma Study Group AML-05 study. This finding was reproduced in AML without a core-binding factor in the Children's Oncology Group study cohort. High CD25 expression has prognostic significance in pediatric AML.

TP53 and RB1 alterations characterize poor prognostic subgroups in pediatric acute myeloid leukemia.

Pediatric acute myeloid leukemia (AML) is a poor prognostic subtype of pediatric leukemia. However, the detailed characteristics of many genetic abnormalities are yet to be established in this disease. Although TP53 and RB1 are established as representative tumor suppressor genes in various cancers, alterations of these two genes, especially RB1, have not been characterized in pediatric AML. We performed next-generation sequencing in 328 pediatric AML patients from the Japanese AML-05 trial to ascertain TP53 and RB1 alterations, and their prognostic implications. We identified seven patients with TP53 alterations (2.1%) and six patients with RB1 alterations (1.8%). These alterations were found in only patients without RUNX1::RUNX1T1, CBFB::MYH11, or KMT2A rearrangements. TP53 and RB1 were frequently co-deleted with their neighboring genes PRPF8 and ELF1, respectively. Patients with TP53 alterations had significantly lower 5-year overall survival (OS; 14.3% vs. 71.4%, p < 0.001) and lower 5-year event-free survival (EFS; 0% vs. 56.3%, p < 0.001); similarly, patients with RB1 had significantly lower 5-year OS (0% vs. 71.8%, p < 0.001) and lower 5-year EFS (0% vs. 56.0%, p < 0.001) when compared to patients without these alterations. In gene expression analyses, oxidative phosphorylation, glycolysis, and protein secretion were upregulated in patients with TP53 and/or RB1 alterations. Additionally, Kaplan-Meier analysis revealed that high expressions of SLC2A5, KCNAB2, and CD300LF were related to poor OS of non-core-binding factor AML patients (p < 0.001, p = 0.001, and p = 0.021, respectively). This study will contribute to the development of risk-stratified therapy and precision medicine in pediatric AML.

UBTF-internal tandem duplication as a novel poor prognostic factor in pediatric acute myeloid leukemia.

The prognosis of pediatric acute myeloid leukemia (AML) has improved via stratification therapy. However, relapse or death occurs in 30%-40% of cases. Novel genetic factors for pediatric AML need to be elucidated to improve prognosis. We detected recurrent internal tandem duplication in upstream binding transcription factor (UBTF-ITD) in 1.2% (6/503) of Japanese pediatric patients with de novo AML. No UBTF-ITD was detected in 175 adult patients with AML or in 65 cell lines that included 15 AML, 39 acute lymphoblastic leukemia, five chronic myeloid leukemia, and six neuroblastoma cell lines. All UBTF-ITDs were found in exon 13 and shared a duplicated region. UBTF-ITD was more frequently detected in patients with trisomy 8, FLT3-ITD, WT1 mutation, and/or high PRDM16 expression (trisomy 8, 3/6; FLT3-ITD, 5/6; WT1 mutation, 2/6; and high PRDM16 expression, 6/6). Gene expression patterns of patients with UBTF-ITD were similar to those of patients with NUP98::NSD1 or FUS::ERG. Survival analysis of the AML-05 cohort revealed that patients with UBTF-ITD had worse outcomes than those without UBTF-ITD (3-year event-free survival, 20% vs. 55%; 3-year overall survival, 40% vs. 74%). Moreover, among the 27 patients with trisomy 8, all three patients with UBTF -ITD had a poor prognosis resulting in early events (relapse or non-complete remission) within 1 year. Our findings suggest that UBTF-ITD may be a novel and significant prognostic factor for pediatric patients with AML.

YM155 and chrysin cooperatively suppress survivin expression in SMARCB1/INI1-deficient tumor cells.

SMARCB1/INI1 deficiency is seen in several malignant tumors including malignant rhabdoid tumor (MRT), a highly aggressive pediatric malignancy. Loss of SMARCB1/INI1 function alters diverse oncogenic cellular signals, making it difficult to discover effective targeting therapy. By utilizing an in vitro drug screening system, effective therapeutic agents against SMARCB1/INI1-deficient tumors were explored in this study. In the in vitro drug sensitivity test, 80 agents with various actions were screened for their cytotoxicity in a panel of five SMARCB1/INI1-deficient tumor cell lines. The combination effect was screened based on the Bliss independent model. The growth-inhibitory effect was determined in both the conventional two-dimensional culture and the collagen-embedded three-dimensional culture system. Survivin expression after agent exposure was determined by Western blot analysis. All five cell lines were found to be sensitive to YM155, a selective survivin inhibitor. In the drug combination screening, YM155 showed additive to synergistic effects with various agents including chrysin. Chrysin enhanced YM155-induced apoptosis, but not mitochondrial depolarization upon exposure of SMARCB1/INI1-deficient tumor cells to the two agents for 6 h. YM155 and chrysin synergistically suppressed survivin expression, especially in TTN45 cells in which such suppression was observed as early as 6 h after exposure to the two agents. Survivin is suggested to be a therapeutic target in MRT and other SMARCB1/INI1-deficient tumors. Chrysin, a flavone that is widely distributed in plants, cooperatively suppressed survivin expression and enhanced the cytotoxicity of YM155.

Genome-wide DNA methylation analysis in pediatric acute myeloid leukemia.

We investigated genome-wide DNA methylation patterns in 64 pediatric patients with acute myeloid leukemia (AML). Based on unsupervised clustering with the 567 most variably methylated cytosine guanine dinucleotide (CpG) sites, patients were categorized into 4 clusters associated with genetic alterations. Clusters 1 and 3 were characterized by the presence of known favorable prognostic factors, such as RUNX1-RUNX1T1 fusion and KMT2A rearrangement with low MECOM expression, and biallelic CEBPA mutations (all 8 patients), respectively. Clusters 2 and 4 comprised patients exhibiting molecular features associated with adverse outcomes, namely internal tandem duplication of FLT3 (FLT3-ITD), partial tandem duplication of KMT2A, and high PRDM16 expression. Depending on the methylation values of the 1243 CpG sites that were significantly different between FLT3-ITD+ and FLT3-ITD- AML, patients were categorized into 3 clusters: A, B, and C. The STAT5-binding motif was most frequently found close to the 1243 CpG sites. All 8 patients with FLT3-ITD in cluster A harbored high PRDM16 expression and experienced adverse events, whereas only 1 of 7 patients with FLT3-ITD in the other clusters experienced adverse events. PRDM16 expression levels were also related to DNA methylation patterns, which were drastically changed at the cutoff value of PRDM16/ABL1 = 0.10. The assay for transposase-accessible chromatin sequencing of AMLs supported enhanced chromatin accessibility around genomic regions, such as HOXB cluster genes, SCHIP1, and PRDM16, which were associated with DNA methylation changes in AMLs with FLT3-ITD and high PRDM16 expression. Our results suggest that DNA methylation levels at specific CpG sites are useful to support genetic alterations and gene expression patterns of patients with pediatric AML.

Clinical significance of RAS pathway alterations in pediatric acute myeloid leukemia.

RAS pathway alterations have been implicated in the pathogenesis of various hematological malignancies. However, their clinical relevance in pediatric acute myeloid leukemia (AML) is not well characterized. We analyzed the frequency, clinical significance, and prognostic relevance of RAS pathway alterations in 328 pediatric patients with de novo AML. RAS pathway alterations were detected in 80 (24.4%) of 328 patients: NF1 (n=7, 2.1%), PTPN11 (n=15, 4.6%), CBL (n=6, 1.8%), NRAS (n=44, 13.4%), KRAS (n=12, 3.7%). Most of these alterations in the RAS pathway were mutually exclusive also together with other aberrations of signal transduction pathways such as FLT3-ITD (P=0.001) and KIT mutation (P=0.004). NF1 alterations were frequently detected in patients with complex karyotype (P=0.031) and were found to be independent predictors of poor overall survival (OS) in multivariate analysis (P=0.007). At least four of seven patients with NF1 alterations had biallelic inactivation. NRAS mutations were frequently observed in patients with CBFB-MYH11 and were independent predictors of favorable outcomes in multivariate analysis (OS, P=0.023; event-free survival [EFS], P=0.037). Patients with PTPN11 mutations more frequently received stem cell transplantation (P=0.035) and showed poor EFS than patients without PTPN11 mutations (P=0.013). Detailed analysis of RAS pathway alterations may enable a more accurate prognostic stratification of pediatric AML and may provide novel therapeutic molecular targets related to this signal transduction pathway.

C/EBPß induces B-cell acute lymphoblastic leukemia and cooperates with BLNK mutations.

BLNK (BASH/SLP-65) encodes an adaptor protein that plays an important role in B-cell receptor (BCR) signaling. Loss-of-function mutations in this gene are observed in human pre-B acute lymphoblastic leukemia (ALL), and a subset of Blnk knock-out (KO) mice develop pre-B-ALL. To understand the molecular mechanism of the Blnk mutation-associated pre-B-ALL development, retroviral tagging was applied to KO mice using the Moloney murine leukemia virus (MoMLV). The Blnk mutation that significantly accelerated the onset of MoMLV-induced leukemia and increased the incidence of pre-B-ALL Cebpb was identified as a frequent site of retroviral integration, suggesting that its upregulation cooperates with Blnk mutations. Transgenic expression of the liver-enriched activator protein (LAP) isoform of Cebpb reduced the number of mature B-lymphocytes in the bone marrow and inhibited differentiation at the pre-BI stage. Furthermore, LAP expression significantly accelerated leukemogenesis in Blnk KO mice and alone acted as a B-cell oncogene. Furthermore, an inverse relationship between BLNK and C/EBPß expression was also noted in human pre-B-ALL cases, and the high level of CEBPB expression was associated with short survival periods in patients with BLNK-downregulated pre-B-ALL. These results indicate the association between the C/EBPß transcriptional network and BCR signaling in pre-B-ALL development and leukemogenesis. This study gives insight into ALL progression and suggests that the BCR/C/EBPß pathway can be a therapeutic target.

Characteristics of genetic alterations of peripheral T-cell lymphoma in childhood including identification of novel fusion genes: the Japan Children's Cancer Group (JCCG).

Peripheral T-cell lymphoma (PTCL) is a group of heterogeneous non-Hodgkin lymphomas showing a mature T-cell or natural killer cell phenotype, but its molecular abnormalities in paediatric patients remain unclear. By employing next-generation sequencing and multiplex ligation-dependent probe amplification of tumour samples from 26 patients, we identified somatic alterations in paediatric PTCL including Epstein-Barr virus (EBV)-negative (EBV- ) and EBV-positive (EBV+ ) patients. As recurrent mutational targets for PTCL, we identified several previously unreported genes, including TNS1, ZFHX3, LRP2, NCOA2 and HOXA1, as well as genes previously reported in adult patients, e.g. TET2, CDKN2A, STAT3 and TP53. However, for other reported mutations, VAV1-related abnormalities were absent and mutations of NRAS, GATA3 and JAK3 showed a low frequency in our cohort. Concerning the association of EBV infection, two novel fusion genes: STAG2-AFF2 and ITPR2-FSTL4, and deletion and alteration of CDKN2A/2B, LMO1 and HOXA1 were identified in EBV- PTCL, but not in EBV+ PTCL. Conversely, alterations of PCDHGA4, ADAR, CUL9 and TP53 were identified only in EBV+ PTCL. Our observations suggest a clear difference in the molecular mechanism of onset between paediatric and adult PTCL and a difference in the characteristics of genetic alterations between EBV- and EBV+ paediatric PTCL.

Droplet digital polymerase chain reaction assay for the detection of the minor clone of KIT D816V in paediatric acute myeloid leukaemia especially showing RUNX1-RUNX1T1 transcripts.

KIT D816V mutation within exon 17 has been particularly reported as one of the poor prognostic factors in pediatric acute myeloid leukemia (AML) with RUNX1-RUNX1T1. The exact frequency and the prognostic impact of KIT D816V minor clones at diagnosis were not examined. In this study, the minor clones were examined and the prognostic significance of KIT D816V mutation in pediatric patients was investigated. Consequently, 24 KIT D816V mutations (7.2%) in 335 pediatric patients were identified, and 12 of 24 were only detected via the digital droplet polymerase chain reaction method. All 12 patients were confined in core binding factor (CBF)-AML patients. The 5 year event-free survival of the patients with KIT D816V mutation was significantly inferior to those without KIT D816V mutation (44.1% [95% confidence interval (CI), 16.0%-69.4%] vs. 74.7% [95% CI, 63.0%-83.2%] P-value = 0.02, respectively). The 5 year overall survival was not different between the two groups (92.9% [95% CI, 59.0%-NA vs. 89.7% [95% CI, 69.6%-96.8%] P-value = 0.607, respectively). In this study, KIT D816V minor clones in patients with CBF-AML were confirmed and KIT D816V was considered as a risk factor for relapse in patients with RUNX1-RUNX1T1-positive AML.

Clinical features of 35 Down syndrome patients with transient abnormal myelopoiesis at a single institution.

Transient abnormal myelopoiesis (TAM) is a unique clonal myeloproliferation characterized by immature megakaryoblasts that occurs in 5-10% of neonates with Down syndrome (DS). Although TAM regresses spontaneously in most patients, approximately 20% of TAM cases result in early death, and approximately 20% of survivors develop acute megakaryoblastic leukemia (AMKL). We retrospectively reviewed records of 35 DS patients with TAM to determine the correlation between clinical characteristics and blast percentage. Thirteen of the 35 patients were classified as low blast percentage TAM (LBP-TAM), defined as TAM with a peak peripheral blast percentage ≤ 10%. Although no patient with LBP-TAM experienced systemic edema, disseminated intravascular coagulation, or early death, eight patients had elevated direct bilirubin levels (> 2 mg/dl) and one developed AMKL. All patients with LBP-TAM had serum markers of liver fibrosis that exceeded the normal limits, and two patients underwent liver biopsy to clarify the etiology of pathological jaundice. Taken together, our results suggest that patients with LBP-TAM may be at risk of liver fibrosis and liver failure, similarly to patients with classical TAM. Although these patients generally have a good prognosis, they should be carefully monitored for potential development of liver disease and leukemia.

Association of high-risk neuroblastoma classification based on expression profiles with differentiation and metabolism.

Neuroblastoma, the most common extracranial solid malignancy among children, originates from undifferentiated neural crest cells (NCC). Despite recent intensified treatment, high-risk patients still have a high mortality rate. To explore a new therapeutic strategy, we performed an integrated genomic and transcriptomic analysis of 30 high-risk neuroblastoma cases. Based on the expression profiling of RNA sequencing, neuroblastoma was classified into Mesenchymal (MES; n = 5) and Noradrenergic (ADRN; n = 25) clusters, as previously reported in the super-enhancer landscape. The expression patterns in MES-cluster cases were similar to normal adrenal glands, with enrichment in secretion-related pathways, suggesting chromaffin cell-like features built from NCC-derived Schwann cell precursors (SCPs). In contrast, neuron-related pathways were enriched in the ADRN-cluster, indicating sympathoblast features reported to originate from NCC but not via SCPs. Thus, MES- and ADRN-clusters were assumed to be corresponding to differentiation pathways through SCP and sympathoblast, respectively. ADRN-cluster cases were further classified into MYCN- and ATRX-clusters, characterized by genetic alterations, MYCN amplifications and ATRX alterations, respectively. MYCN-cluster cases showed high expression of ALDH18A1, encoding P5CS related to proline production. As reported in other cancers, this might cause reprogramming of proline metabolism leading to tumor specific proline vulnerability candidate for a target therapy of metabolic pathway. In ATRX-cluster, SLC18A2 (VMAT2), an enzyme known to prevent cell toxicity due to the oxidation of dopamine, was highly expressed and VMAT2 inhibitor (GZ-793A) represented significant attenuation of cell growth in NB-69 cell line (high SLC18A2 expression, no MYCN amplification) but not in IMR-32 cell line (MYCN amplification). In addition, the correlation of VMAT2 expression with metaiodobenzylguanidine (MIBG) avidity suggested a combination of VMAT2 inhibitor and MIBG radiation for a novel potential therapeutic strategy in ATRX-cluster cases. Thus, targeting the characteristics of unique neuroblastomas may prospectively improve prognosis.

Comprehensive genetic analysis of pediatric germ cell tumors identifies potential drug targets.

To elucidate the molecular pathogenesis of pediatric germ cell tumors (GCTs), we performed DNA methylation array analysis, whole transcriptome sequencing, targeted capture sequencing, and single-nucleotide polymorphism array analysis using 51 GCT samples (25 female, 26 male), including 6 germinomas, 2 embryonal carcinomas, 4 immature teratomas, 3 mature teratomas, 30 yolk sac tumors, and 6 mixed germ cell tumors. Among the 51 samples, 11 were from infants, 23 were from young children, and 17 were from those aged ≥10 years. Sixteen of the 51 samples developed in the extragonadal regions. Germinomas showed upregulation of pluripotent genes and global hypomethylation. Pluripotent genes were also highly expressed in embryonal carcinomas. These genes may play essential roles in embryonal carcinomas given that their binding sites are hypomethylated. Yolk sac tumors exhibited overexpression of endodermal genes, such as GATA6 and FOXA2, the binding sites of which were hypomethylated. Interestingly, infant yolk sac tumors had different DNA methylation patterns from those observed in older children. Teratomas had higher expression of ectodermal genes, suggesting a tridermal nature. Based on our results, we suggest that KIT, TNFRSF8, and ERBB4 may be suitable targets for the treatment of germinoma, embryonal carcinomas, and yolk sac tumors, respectively.

Integrated multiomics analysis of hepatoblastoma unravels its heterogeneity and provides novel druggable targets.

Although hepatoblastoma is the most common pediatric liver cancer, its genetic heterogeneity and therapeutic targets are not well elucidated. Therefore, we conducted a multiomics analysis, including mutatome, DNA methylome, and transcriptome analyses, of 59 hepatoblastoma samples. Based on DNA methylation patterns, hepatoblastoma was classified into three clusters exhibiting remarkable correlation with clinical, histological, and genetic features. Cluster F was largely composed of cases with fetal histology and good outcomes, whereas clusters E1 and E2 corresponded primarily to embryonal/combined histology and poor outcomes. E1 and E2, albeit distinguishable by different patient age distributions, were genetically characterized by hypermethylation of the HNF4A/CEBPA-binding regions, fetal liver-like expression patterns, upregulation of the cell cycle pathway, and overexpression of NQO1 and ODC1. Inhibition of NQO1 and ODC1 in hepatoblastoma cells induced chemosensitization and growth suppression, respectively. Our results provide a comprehensive description of the molecular basis of hepatoblastoma and rational therapeutic strategies for high-risk cases.

Impact of immunophenotypic characteristics on genetic subgrouping in childhood acute lymphoblastic leukemia: Tokyo Children's Cancer Study Group (TCCSG) study L04-16.

Immunophenotyping was performed in 1044 consecutive childhood acute lymphoblastic leukemia (ALL) patients enrolled in the Tokyo Children's Cancer Study Group L04-16 trial, revealing novel findings associated with genetic abnormalities. In addition to TCF3-PBX1 and MEF2D fusions, the CD10(+) subtype of KMT2A-MLLT3-positive ALL frequently exhibited the cytoplasmic-µ(+) pre-B ALL immunophenotype. Although ETV6-RUNX1 was significantly correlated with myeloid antigen expression, more than half of patients expressed neither CD33 nor CD13, while the CD27(+) /CD44(-) immunophenotype was maintained. Expression of CD117 and CD56 in B-cell precursor-ALL was limited to certain subtypes including ETV6-RUNX1 and KMT2A-MLLT3. Besides BCR-ABL1, CRLF2, hyperdiploidy, and hypodiploidy, CD66c was also expressed in Ph-like kinase fusion-, PAX5 fusion-, and DUX4 fusion-positive ALL, but not in MEF2D fusion-positive ALL, indicating constant selectivity of CD66c expression. In T-ALL, SIL-TAL1-positive patients were likely to exhibit a more mature immunophenotype. Expression of CD21 and CD10 was not rare in T-ALL, while lack of CD28 was an additional feature of early T-cell precursor-ALL. Considering the immunophenotype as a prognostic maker, MEF2D fusion-positive ALL with CD5 expression may be associated with a poorer prognosis in comparison with those lacking CD5 expression. In cases with characteristic marker expression, the presence of certain fusion transcripts could be predicted accurately.

Nationwide epidemiological survey of familial myelodysplastic syndromes/acute myeloid leukemia in Japan: a multicenter retrospective study.

Although several pedigrees of familial myelodysplastic syndromes/acute myeloid leukemia (fMDS/AML) have been reported, the epidemiology and clinical features has been poorly understood. To explore the epidemiology of this entity, we performed a retrospective nationwide epidemiological survey in Japan using questionnaire sheets. The questionnaire was sent to 561 institutions or hospitals certified by Japanese Society of Hematology, unearthing the existence of 41 pedigrees of fMDS/AML. Among them, we obtained the clinical information of 31 patients in 20 pedigrees. The median age of the initial diagnosis was 51 years (range 9-88 years) and the WHO classification 2008 ranged from refractory anemia (RA) to AML. Focusing on the familial MDS patients, refractory anemia with excess blasts (RAEB)-2 was the largest group (27.3%). The median overall survival (OS) of fMDS and fAML in this study were 71.6 and 12.4 months, and the five-year OS were 61.3 and 50%, respectively.