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Summary: The criteria of myelodysplastic syndromes (MDS) with mutated SFB31 (MDS‐SFB31) proposed by the 5th edition of the WHO classification (WHO 2022) and the International Consensus Classification (ICC) need validation. We analysed 125 consecutive MDS cases with SFB31 mutation or ring sideroblasts (RS) ≥15% without excess blasts. We found that SFB31‐negative MDS with RS had significantly different clinical features and worse prognosis. According to WHO 2022, the detection of ≥15% RS may substitute for SF3B1 mutation and our analyses support this proposal for similar prognosis of two groups after excluding high‐risk genetic features referred by WHO 2022. Patients with variant allele frequency (VAF) <10% SFB31 tend to have briefer survival, supporting the VAF 10% threshold of ICC. Patients with multilineage dysplasia (MLD) had significantly shorter OS than those with single lineage dysplasia. MLD is still a powerful morphological marker of worse outcome in WHO 2022 and ICC‐defined MDS‐SF3B1. [ABSTRACT FROM AUTHOR]

Myelodysplastic neoplasms (MDS) with ring sideroblasts (RS) are diagnosed via bone marrow aspiration in the presence of either (i) ≥15% RS or (ii) 5–14% RS and an SF3B1 mutation. In the MEDALIST trial and in an interim analysis of the COMMANDS trial, lower-risk MDS-RS patients had decreased transfusion dependency with luspatercept treatment. A total of 6817 patients with suspected hematologic malignancies underwent molecular testing using a next-generation-sequencing-based genetic assay and 395 MDS patients, seen at our centre from 1 January 2018 to 31 May 2023, were reviewed. Of these, we identified 39 evaluable patients as having lower-risk MDS with SF3B1 mutations: there were 20 (51.3%) males and 19 (48.7%) females, with a median age of 77 years (range of 57 to 92). Nineteen (48.7%) patients had an isolated SF3B1 mutation with a mean variant allele frequency of 35.2% +/− 8.1%, ranging from 7.4% to 46.0%. There were 29 (74.4%) patients with ≥15% RS, 6 (15.4%) with 5 to 14% RS, one (2.6%) with 1% RS, and 3 (7.7%) with no RS. Our study suggests that a quarter of patients would be missed based on the morphologic criterion of only using RS greater than 15% and supports the revised 2022 definitions of the World Health Organization (WHO) and International Consensus Classification (ICC), which shift toward molecularly defined subtypes of MDS and appropriate testing.

Myelodysplastic neoplasms (MDS) with ring sideroblasts (RS) are diagnosed via bone marrow aspiration in the presence of either (i) ≥15% RS or (ii) 5–14% RS and an SF3B1 mutation. In the MEDALIST trial and in an interim analysis of the COMMANDS trial, lower-risk MDS-RS patients had decreased transfusion dependency with luspatercept treatment. A total of 6817 patients with suspected hematologic malignancies underwent molecular testing using a next-generation-sequencing-based genetic assay and 395 MDS patients, seen at our centre from 1 January 2018 to 31 May 2023, were reviewed. Of these, we identified 39 evaluable patients as having lower-risk MDS with SF3B1 mutations: there were 20 (51.3%) males and 19 (48.7%) females, with a median age of 77 years (range of 57 to 92). Nineteen (48.7%) patients had an isolated SF3B1 mutation with a mean variant allele frequency of 35.2% +/− 8.1%, ranging from 7.4% to 46.0%. There were 29 (74.4%) patients with ≥15% RS, 6 (15.4%) with 5 to 14% RS, one (2.6%) with 1% RS, and 3 (7.7%) with no RS. Our study suggests that a quarter of patients would be missed based on the morphologic criterion of only using RS greater than 15% and supports the revised 2022 definitions of the World Health Organization (WHO) and International Consensus Classification (ICC), which shift toward molecularly defined subtypes of MDS and appropriate testing. [ABSTRACT FROM AUTHOR]

Simple Summary: Myelodysplastic syndromes/myeloproliferative neoplasms (MDS/MPN) are entities that have been quite difficult to define since their discovery. At the time of presentation, they possess features of both myelodysplastic syndromes and myeloproliferative neoplasms. Because of this overlap, there has been an inherent difficulty in the diagnosis and classification of these neoplasms. The recent World Health Organization (WHO) 2022 classification and the International Consensus Classification (ICC) improved the diagnostic criteria for these disorders. In this review, we describe the main entities, highlighting the differential diagnosis. The myelodysplastic syndromes/myeloproliferative neoplasms (MDS/MPN) category comprises a varied group of myeloid neoplastic diseases characterized by clinical and pathologic overlapping features of both myelodysplastic and myeloproliferative neoplasms. For these reasons, these tumors are challenging in terms of diagnosis. The recent World Health Organization (WHO) 2022 classification and the International Consensus Classification (ICC) made changes in the classification of MDS/MPN compared to the previous 2016 WHO classification and improved the diagnostic criteria of these entities. The aim of this review is to describe the main entities reported in the more recent classifications, focusing on chronic myelomonocytic leukemia (CMML), MDS/MPN with neutrophilia (or atypical CML [aCML]), and MDS/MPN with SF3B1 mutation and thrombocytosis/MDS/MPN with ring sideroblasts and thrombocytosis. A particular emphasis is given to the differential diagnosis and analysis of subtle divergences and semantic differences between the WHO classification and the ICC for these entities. [ABSTRACT FROM AUTHOR]

Abstract Background Recently, a hotspot mutation in prolactinoma was observed in splicing factor 3b subunit 1 (SF3B1 R625H ), but its functional effects and underlying molecular mechanisms remain largely unexplored. Methods Using the CRISPR/Cas9 genome editing system and rat pituitary GH3 cells, we generated heterozygous Sf3b1 R625H mutant cells. Sanger and whole-genome sequencing were conducted to verify the introduction of this mutation. Transcriptome analysis was performed in SF3B1-wild-type versus mutant human prolactinoma samples and GH3 cells. RT-PCR and minigene reporter assays were conducted to verify aberrant splicing. The functional consequences of SF3B1 R625H were evaluated in vitro and in vivo. Critical makers of epithelial-mesenchymal transition and key components were detected using western blot, immunohistochemistry, and immunofluorescence. Suppressing proteins was achieved using siRNA. Results Transcriptomic analysis of prolactinomas and heterozygous mutant cells revealed that the SF3B1 R625H allele led to different alterations in splicing properties, affecting different genes in different species. SF3B1R625H promoted aberrant splicing and DLG1 suppression in both rat cells and human tumors. In addition, SF3B1R625H and knocking down DLG1 promoted cell migration, invasion, and epithelial-mesenchymal transition through PI3K/Akt pathway. Conclusions Our findings elucidate a mechanism through which mutant SF3B1 promotes tumor progression and may provide a potent molecular therapeutic target for prolactinomas with the SF3B1 R625H mutation.

Simple Summary: This review updates recent advances in the pathogenesis, diagnosis, and therapy of prolactinoma. Prolactinomas, comprising 30–50% of all pituitary neuroendocrine tumors, frequently occur in females aged 20 to 50 and cause hypogonadism and infertility. In typical cases, female patients exhibit galactorrhea and amenorrhea due to serum prolactin (PRL) elevation, and during pregnancy, they should be carefully treated. During diagnosis, other causes of hyperprolactinemia must be excluded, and an MRI is useful for detecting pituitary neuroendocrine tumors. For the treatment of prolactinoma, dopamine agonists are effective in decreasing PRL levels and shrinking tumor size in most patients. Surgical treatment is recommended for patients who are resistant or intolerant to dopamine agonists. This review also discusses giant and malignant prolactinomas, prolactinoma-associated pregnancy, and new therapeutic approaches. Prolactinomas comprise 30–50% of all pituitary neuroendocrine tumors, frequently occur in females aged 20 to 50, and cause hypogonadism and infertility. In typical cases, female patients exhibit galactorrhea and amenorrhea due to serum prolactin (PRL) elevation, and patients during pregnancy should be carefully treated. During diagnosis, other causes of hyperprolactinemia must be excluded, and an MRI is useful for detecting pituitary neuroendocrine tumors. For treating prolactinoma, dopamine agonists (DAs) are effective for decreasing PRL levels and shrinking tumor size in most patients. Some DA-resistant cases and the molecular mechanisms of resistance to a DA are partially clarified. The side effects of a DA include cardiac valve alterations and impulse control disorders. Although surgical therapies are invasive, recent analysis shows that long-term remission rates are higher than from medical therapies. The treatments for giant or malignant prolactinomas are challenging, and the combination of medication, surgery, and radiation therapy should be considered. Regarding pathogenesis, somatic SF3B1 mutations were recently identified even though molecular mechanisms in most cases of prolactinoma have not been elucidated. To understand the pathogenesis of prolactinomas, the development of new therapeutic approaches for treatment-resistant patients is expected. This review updates the recent advances in understanding the pathogenesis, diagnosis, and therapy of prolactinoma. [ABSTRACT FROM AUTHOR]

The outcomes of myelodysplastic syndrome (MDS) patients with SF3B1 mutation, despite identified as a favorable prognostic biomarker, are variable. To comprehend the heterogeneity in clinical characteristics and outcomes, we reviewed 140 MDS patients with SF3B1 mutation in Zhejiang province of China. Seventy-three (52.1%) patients diagnosed as MDS with ring sideroblasts (MDS-RS) following the 2016 World Health Organization (WHO) classification and 118 (84.3%) patients belonged to lower risk following the revised International Prognostic Scoring System (IPSS-R). Although clonal hematopoiesis-associated mutations containing TET2 , ASXL1 and DNMT3A were the most frequent co-mutant genes in these patients, RUNX1, EZH2, NF1 and KRAS/NRAS mutations had significant effects on overall survival (OS). Based on that we developed a risk scoring model as IPSS-R×0.4+ RUNX1 ×1.1+ EZH2 ×0.6+ RAS ×0.9+ NF1 ×1.6. Patients were categorized into two subgroups: low-risk (L-R, score <= 1.4) group and high risk (H-R, score > 1.4) group. The 3-year OS for the L-R and H-R groups was 91.88% (95% CI, 83.27%-100%) and 38.14% (95% CI, 24.08%-60.40%), respectively (P<0.001). This proposed model distinctly outperformed the widely used IPSS-R. In summary, we constructed and validated a personalized prediction model of MDS patients with SF3B1 mutation that can better predict the survival of these patients. [ABSTRACT FROM AUTHOR]

We present the case of a 56-year-old male patient with paravertebral extramedullary hematopoiesis (EMH) secondary to myelodysplastic syndrome with ring sideroblasts and multilineage dysplasia. In a routine health checkup over 5 years prior, he presented with asymptomatic mild anemia and a posterior mediastinal mass. Pathological and cytomorphological findings of the resected paravertebral mass were similar to those of his bone marrow specimen, and included cellularity with erythroid hyperplasia, multilineage dysplastic changes, and the presence of ring sideroblasts. A concordant SF3B1 mutation was detected in both bone marrow and paravertebral mass samples, suggesting that the EMH cells were derived from the bone marrow. [ABSTRACT FROM AUTHOR]

The outcomes of myelodysplastic syndrome (MDS) patients with SF3B1 mutation, despite identified as a favorable prognostic biomarker, are variable. To comprehend the heterogeneity in clinical characteristics and outcomes, we reviewed 140 MDS patients with SF3B1 mutation in Zhejiang province of China. Seventy-three (52.1%) patients diagnosed as MDS with ring sideroblasts (MDS-RS) following the 2016 World Health Organization (WHO) classification and 118 (84.3%) patients belonged to lower risk following the revised International Prognostic Scoring System (IPSS-R). Although clonal hematopoiesis-associated mutations containing TET2, ASXL1 and DNMT3A were the most frequent co-mutant genes in these patients, RUNX1, EZH2, NF1 and KRAS/NRAS mutations had significant effects on overall survival (OS). Based on that we developed a risk scoring model as IPSS-R×0.4+RUNX1×1.1+EZH2×0.6+RAS×0.9+NF1×1.6. Patients were categorized into two subgroups: low-risk (L-R, score 1.4) group. The 3-year OS for the L-R and H-R groups was 91.88% (95% CI, 83.27%-100%) and 38.14% (95% CI, 24.08%-60.40%), respectively (P

Background: Recently, a hotspot mutation in prolactinoma was observed in splicing factor 3b subunit 1 (SF3B1R625H), but its functional effects and underlying molecular mechanisms remain largely unexplored. Methods: Using the CRISPR/Cas9 genome editing system and rat pituitary GH3 cells, we generated heterozygous Sf3b1R625H mutant cells. Sanger and whole-genome sequencing were conducted to verify the introduction of this mutation. Transcriptome analysis was performed in SF3B1-wild-type versus mutant human prolactinoma samples and GH3 cells. RT-PCR and minigene reporter assays were conducted to verify aberrant splicing. The functional consequences of SF3B1R625H were evaluated in vitro and in vivo. Critical makers of epithelial-mesenchymal transition and key components were detected using western blot, immunohistochemistry, and immunofluorescence. Suppressing proteins was achieved using siRNA. Results: Transcriptomic analysis of prolactinomas and heterozygous mutant cells revealed that the SF3B1R625H allele led to different alterations in splicing properties, affecting different genes in different species. SF3B1R625H promoted aberrant splicing and DLG1 suppression in both rat cells and human tumors. In addition, SF3B1R625H and knocking down DLG1 promoted cell migration, invasion, and epithelial-mesenchymal transition through PI3K/Akt pathway. Conclusions: Our findings elucidate a mechanism through which mutant SF3B1 promotes tumor progression and may provide a potent molecular therapeutic target for prolactinomas with the SF3B1R625H mutation. [ABSTRACT FROM AUTHOR]

Mutations in splicing factor genes have a severe impact on the survival of cancer patients. Splicing factor 3b subunit 1 (SF3B1) is one of the most frequently mutated genes in chronic lymphocytic leukemia (CLL); patients carrying these mutations have a poor prognosis. Since the splicing machinery and the epigenome are closely interconnected, we investigated whether these alterations may affect the epigenomes of CLL patients. While an overall hypomethylation during CLL carcinogenesis has been observed, the interplay between the epigenetic stage of the originating B cells and SF3B1 mutations, and the subsequent effect of the mutations on methylation alterations in CLL, have not been investigated. We profiled the genome-wide DNA methylation patterns of 27 CLL patients with and without SF3B1 mutations and identified local decreases in methylation levels in SF3B1mut CLL patients at 67 genomic regions, mostly in proximity to telomeric regions. These differentially methylated regions (DMRs) were enriched in gene bodies of cancer-related signaling genes, e.g., NOTCH1, HTRA3, and BCL9L. In our study, SF3B1 mutations exclusively emerged in two out of three epigenetic stages of the originating B cells. However, not all the DMRs could be associated with the methylation programming of B cells during development, suggesting that mutations in SF3B1 cause additional epigenetic aberrations during carcinogenesis.

According to 2008 WHO classification RARS is regarded as less than 5% blasts and more than 15% ring sideroblasts in the bone marrow. In 2016 WHO classification MDS-RS is revised as more than 15% ring sideroblasts or more than 5% ring sideroblasts in the presence of the SF3B1 mutation. In our study, we classified intracellular iron in bone marrow into four types according to the size and quantity of iron granules. We found that there was a significant difference between SF3B1-mutant and SF3B1-wild-type MDS patients in intracellular iron III, intracellular iron IV and ring sideroblasts. We defined intracellular iron (III + IV + RS)%×100 as 'Iron score'. We suggest that the patients carrying SF3B1 mutation with Iron score ≥10 will extend the subtype of MDS-RS, in addition to the current WHO classification criteria. This study gives us a new insight into the relation of SF3B1 mutation and intracellular iron in lower-risk MDS. [ABSTRACT FROM AUTHOR]

Myeloid neoplasms with ring sideroblasts are currently categorized within the myelodysplastic syndromes ( MDS) or myelodysplastic/myeloproliferative neoplasms ( MDS/ MPN) in the World Health Organization classification. Recent findings have identified that the presence of ring sideroblasts in these disorders has a unique molecular basis, i.e., the somatic mutation of SF3B1, a gene encoding a splicing factor. Mutations of SF3B1 occur in up to 90% of patients with refractory anaemia with unilineage dysplasia ( RARS) and 70% of those with refractory cytopenia with multilineage dysplasia and ring sideroblasts or RARS associated with marked thrombocytosis. Experimental evidence has shown that mutant SF3B1 results in the abnormal splicing of several genes, primarily due to misrecognition of 3′ splice sites. The resulting aberrant mRNAs undergo nonsense-mediated mRNA decay ( NMD), resulting in haploinsufficiency of canonical transcripts and protein expression. In addition, it is also possible that NMD-insensitive aberrant transcripts are translated into proteins with altered function. Patients with MDS carrying the SF3B1 mutation show a homogeneous disease phenotype characterized by isolated erythroid dysplasia and mild dysplasia in granulocytic or megakaryocytic lineages, supporting the notion that the SF3B1 mutation identifies a distinct entity within MDS. The available evidence suggests that these findings may have relevant impact on the diagnosis, classification and management of patients with these neoplasms. [ABSTRACT FROM AUTHOR]

Mutations in splicing factor genes have a severe impact on the survival of cancer patients. Splicing factor 3b subunit 1 (SF3B1) is one of the most frequently mutated genes in chronic lymphocytic leukemia (CLL); patients carrying these mutations have a poor prognosis. Since the splicing machinery and the epigenome are closely interconnected, we investigated whether these alterations may affect the epigenomes of CLL patients. While an overall hypomethylation during CLL carcinogenesis has been observed, the interplay between the epigenetic stage of the originating B cells and SF3B1 mutations, and the subsequent effect of the mutations on methylation alterations in CLL, have not been investigated. We profiled the genome-wide DNA methylation patterns of 27 CLL patients with and without SF3B1 mutations and identified local decreases in methylation levels in SF3B1mut CLL patients at 67 genomic regions, mostly in proximity to telomeric regions. These differentially methylated regions (DMRs) were enriched in gene bodies of cancer-related signaling genes, e.g., NOTCH1, HTRA3, and BCL9L. In our study, SF3B1 mutations exclusively emerged in two out of three epigenetic stages of the originating B cells. However, not all the DMRs could be associated with the methylation programming of B cells during development, suggesting that mutations in SF3B1 cause additional epigenetic aberrations during carcinogenesis. [ABSTRACT FROM AUTHOR]

Approximately 25% of all uveal melanoma (UM) contain driver mutations in the gene encoding the spliceosome factor SF3B1 , and whilst patients with such SF3B1 mutations generally have an intermediate risk on developing metastatic disease, a third of these patients develop early metastasis within 5 years after diagnosis. We therefore investigated whether clinical and/or genetic variables could be indicative of short progression-free survival (PFS < 60 months) or long PFS (PFS ≥ 60 months) for SF3B1 -mutated ( SF3B1 mut ) UM patients. We collected 146 SF3B1 mut UM from our Rotterdam Ocular Melanoma Studygroup (ROMS) database and external published datasets. After stratification of all SF3B1 mut UM using short PFS vs. long PFS, only largest tumor diameter (LTD) was significantly larger (mean: 17.7 mm (±2.8 SD) in the short PFS SF3B1 mut group vs. the long PFS group (mean: 14.7 (±3.7 SD, p = 0.001). Combined ROMS and The Cancer Genome Atlas (TCGA) transcriptomic data were evaluated, and we identified SF3B1 mut -specific canonical transcripts (e.g., a low expression of ABHD6 indicative for early-onset metastatic disease) or distinct expression of SF3B1 mut UM aberrant transcripts, indicative of early- or late-onset or no metastatic SF3B1 mut UM.

The myelodysplastic syndromes (MDS) are common myeloid malignancies. Mutations in genes encoding different components of the spliceosome occur in more than half of all MDS patients. SF3B1 is the most frequently mutated splicing factor gene in MDS, and there is a strong association between SF3B1 mutations and the presence of ring sideroblasts in the bone marrow of MDS patients. It has been recently proposed that SF3B1 mutant MDS should be recognized as a distinct nosologic entity. Splicing factor mutations cause aberrant pre-mRNA splicing of many target genes, some of which have been shown to impact on hematopoiesis in functional studies. Emerging data show that some of the downstream effects of different mutated splicing factors converge on common cellular processes, such as hyperactivation of NF-κB signaling and increased R-loops. The aberrantly spliced target genes and the dysregulated pathways and cellular processes associated with splicing factor mutations provided the rationale for new potential therapeutic approaches to target MDS cells with mutations of SF3B1 and other splicing factors. [ABSTRACT FROM AUTHOR]

Abstract: Objective: Somatic mutations of SF3B1 gene have recently been identified in myelodysplastic syndrome and chronic lymphocytic leukemia. The frequency and clinical relevance of SF3B1 mutations have been rarely studied in acute myeloid leukemia (AML) and chronic myeloid leukemia (CML). The present study was aimed to analyze the frequency of SF3B1 mutations in AML and CML. Designs and methods: High-resolution melting analysis (HRMA) was established to detect the mutation hotspots (codon E622, H662, K666, and K700) of SF3B1 gene in 275 AML and 81 CML patients. Results: Heterozygous SF3B1 mutations were detected in three AML patients by HRMA. Direct DNA sequencing identified one K666T, one K666N and one K700E mutations. All three AML patients had normal karyotypes. One case also had NPM1 and DNMT3A mutations, one had FLT3 internal tandem duplication and DNMT3A mutations, and the other had NPM1 mutation. No SF3B1 mutations were detected in CML patients. Conclusions: SF3B1 mutation is a rare molecular event in Chinese AML and CML patients. [Copyright &y& Elsevier]

Splicing factor 3B subunit 1 (SF3B1) is a complex takes part in intron splicing of pre-mRNA and mutations within it have been reported frequently in myeloid malignancies including myelodysplastic syndromes (MDS). However, its prognostic value has been controversial. Hence, we aimed this meta-analysis to investigate the prognostic effect of SF3B1 mutations in patients with MDS. Several electronic databases were searched in of EMBASE, PubMed, the Cochrane Library and Web of Science (published up to November 2017) to obtain eligible studies. The pooled Hazard Ratio (HRs) and 95% confidence interval (CI) for overall survival (OS) and leukemia-free survival (LFS) as the primary and secondary endpoint, respectively, were chosen and extracted to determine the prognostic impact of SF3B1 mutations and to compare SF3B1 mutations to those with wild-type. Nine cohort studies with a total of 2259 patients were obtained, and the pooled HRs for OS was 0.93 (95% CI: 0.56-1.52, p-value = 0.78) and revealed no significant effect on overall survival of MDS patients by random effect models. Our meta-analysis suggested that SF3B1 has no impact on OS of patients with MDS, however, an adequately designed prospective study with a large number of patients with different type of SF3B1 mutations is needed to confirm these results. Additionally, Begg's and Egger's tests did not show any publication bias. [ABSTRACT FROM AUTHOR]

Background: Integrating the proportion of ring sideroblasts and SF3B1 mutation status is required for diagnosis of sideroblastic subgroups in myelodysplastic syndrome (MDS) as proposed by the World Health Organization 2016 classification. However, the clinical implications of SF3B1 mutation and ring sideroblasts in MDS-refractory cytopenia with multilineage dysplasia (MDS-RCMD) remain unclear., Patients and Methods: Clinical and laboratory features in 238 MDS-RCMD patients were retrospectively analyzed, and the prognostic significance of SF3B1 mutation and ring sideroblasts on overall survival and leukemia-free survival in total MDS-RCMD patients and different subgroups stratified by the percentage of ring sideroblasts or SF3B1 mutation status were evaluated., Results: MDS-RCMD patients with ring sideroblasts ≥ 15% showed a significantly higher prevalence of SF3B1 mutation compared to ring sideroblasts 5%-14% or ring sideroblasts < 5% (75.6% vs. 15.1% vs. 6.4%, P < .001). In multivariate analysis, SF3B1 mutation was associated with a significantly prolonged survival (hazard ratio [HR] = 0.430, P = .013) and reduced leukemic transformation (HR = 0.174, P = .021) in total MDS-RCMD patients, while ring sideroblasts showed no independent effect on either survival or leukemic transformation. There were no significant differences in clinical characteristics or survival between MDS-RCMD patients with ring sideroblasts ≥ 15% and ring sideroblasts 5%-14% in the presence of SF3B1 mutation. Furthermore, SF3B1 mutation showed an independent prognostic effect on overall survival in MDS-RCMD patients with ring sideroblasts 5%-14% (HR = 0.195, P = .046)., Conclusion: SF3B1 mutation, not the presence of ring sideroblasts, identifies a distinct subtype and showed independent prognostic value on survival and leukemia transformation in MDS-RCMD patients., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Myelodysplastic/myeloproliferative neoplasm (MDS/MPN) with ring sideroblasts and thrombocytosis (MDS/MPN with RS-T), which exhibits both an increased number of marrow ring sideroblasts and thrombocytosis, is a rare disorder classified as one of the newly established forms of MDS/MPN in the WHO 2016 classification. A 77-year-old female with marked thrombocytosis of 1,024×10 9 /L was tentatively diagnosed with essential thrombocythemia in 2011, and the thrombocytosis was controlled using hydroxycarbamide and low-dose busulfan. In 2016, the leukocyte count increased to a peak value of 68.8×10 9 /L (86.6% mature neutrophils) during platelet-reduction therapy. Bone marrow aspirate exhibited hypercellularity with ring sideroblasts comprising 41.5% erythroblasts without excess myeloblasts. Cytogenetic examination demonstrated the JAK2 V617F mutation and chromosomal abnormality of 46,XX,del(20)(q1?). Furthermore, dysplastic features of erythroid and granuloid precursors, as well as many large atypical megakaryocytes, were observed. Further genetic examinations revealed the SF3B1 K700E mutation, but not amplification of the JAK2 gene or pathogenic mutations in the 13 other genes examined. A diagnosis of MDS/MPN with RS-T was established and hyperleukocytosis was controlled using a higher dose of hydroxycarbamide. Although the patient maintained a stable disease state, she became RBC transfusion-dependent. Hyperleukocytosis, regardless of chemotherapy, is rare and may be novel in this disorder.

Genetic mutations in genes encoding critical component of RNA splicing machinery including SF3B1 are frequently identified and recognized as the pathogenesis in the development of myelodysplatic syndrome (MDS). In this study, PCR sequencings specific for SF3B1 exon 13, 14, 15, and 16 were performed to analyse genomic DNA isolated from bone marrow samples of 72 newly diagnosed MDS patients. We found that 10 of 72 (14%) patients harbor SF3B1 missense mutations including E622D (1/72), R625C/G (2/72), H662Q (1/72), K666T (1/72), K700E (4/72) and G740E (1/72), respectively. Mutations were predominantly located on exon 14 and 15 of SF3B1 coding sequence. Interestingly, patients with SF3B1 mutations exhibited higher platelet counts (195×109/L VS. 140×109/L, p-value = 0.025) as well as lower hemoglobin levels (81 g/L VS. 92 g/L, p-value = 0.009) and associated with ring sideroblast phenotype (p-value < 0.001) when compared with patients without the SF3B1 mutation. In summary, we reported the frequency of SF3B1 mutations in Thai patients with different subtypes of MDS. SF3B1 mutations were predominantly occurred in MDS-RS and considered as favourable prognosis value. This study further highlighted the clinical important of SF3B1 mutations analysis for the classification of MDS., (Creative Commons Attribution License)

Splicing factor mutations represent a novel class of driver mutations in myelodysplastic syndromes, where four genes, including SF3B1, SRSF2, U2AF1, and ZRSR2, are most frequently affected. SF3B1 and SRSF2 mutations show prominent specificity to the syndrome subtypes characterized by increased ring sideroblasts and chronic myelomonocytic leukemia, respectively. These mutations are suspected to be involved in the pathogenesis of the above mentioned syndromes most likely via abnormal RNA splicing. However, the precise mechanism and target genes have not been fully understood. Splicing alterations induced by these mutations are extensively studied using RNA sequencing. SF3B1 mutations caused misrecognition of 3' splice sites. Target genes included those involved in mitochondrial iron metabolism or heme biosynthesis, such as ABCB7 and PPOX, suggesting a role in the abnormal erythropoiesis associated with increased ring sideroblasts. By contrast, SRSF2 and U2AF1 mutations were mainly associated with alternative exon usage in hundreds of genes. The targets included genes of which mutations are definitive or putative drivers in myeloid malignancies. Protein structure modeling and experiments with cell lines and mouse models supported these findings. ZRSR2 mutations were associated with the retention of U12-type introns, and this is consistent with the known role of ZRSR2 as an essential component of the U12-type spliceosome. Further studies are warranted to determine the biological effects of splicing alterations.

The purpose of this study was to explore the relationship between SF3B1 mutations and the prognoses of patients with breast cancer. Clinical and SF3B1 mutation data from The Cancer Genome Atlas were analyzed. SF3B1 mutations were evaluated as prognostic factors in all breast cancer patients and specific subgroups through Cox regression and Kaplan-Meier analyses. We also investigated the relationship between traditional parameters and SF3B1 mutations. Receiver operating characteristics curves were used to analyze common risk factors for their sensitivity and specificity in predicting SF3B1 mutations. SF3B1 mutations were a poor prognostic factor in luminal B and progesterone receptor (PR)-negative breast cancer ( P < 0.01). Age at diagnosis and estrogen receptor (ER) status were associated with SF3B1 mutations in all breast cancers ( P < 0.01) and in luminal B and PR-negative subgroups ( P < 0.01). The age at diagnosis and ER status combined had a higher sensitivity and specificity for predicting SF3B1 mutations than each factor alone. SF3B1 mutations are a poor prognostic factor in luminal B and PR-negative breast cancer patients. These mutations are significantly associated with age at diagnosis and ER status. SF3B1 mutations may therefore be a novel therapeutic target for breast cancer patients., Competing Interests: CONFLICTS OF INTEREST The authors declare that they have no conflicts of interest.

Objective: To clarify the possible biological differences and implication of the SF3B1 gene for patients with MDS-RS (myelodysplastic syndromes with ring sideroblasts)., Methods: Sanger sequencing was performed on mutation hotspots of the SF3B1 gene in MDS-RS patients. The differences between the SF3B1 mutated and wild-type subsets, including the ultrastructure of erythroid precursors, iron profile parameters, erythropoiesis-related measurements, as well as clinical features, were analyzed., Results: SF3B1 mutations were detected in 33 out of fifty-two MDS-RS patients (63%). The vast majority of patients with mutations (94%) were categorized in the lower risk group according to the IPSS (International Prognostic Scoring System), in contrast to only fifty-eight percent of the wild-type cases. In addition to the notably higher percentages of erythroblasts and ring sideroblasts in patients with mutations, abundant electron-dense granules in the mitochondria of the erythroid precursors were clearly observed. Moreover, patients with mutations presented both improper iron uptake and distribution (lower serum hepcidin-25 concentration, P=0.028) and enhanced erythropoietic activity (higher soluble transferrin receptor level, P=0.132; higher growth differentiation factor 15 concentration, P<0.001). Finally, MDS-RS patients carrying SF3B1 mutations had a better overall survival (median 38 vs. 18 months, P=0.001) compared to those without mutations. By multivariable analysis, the prognostic significance of the SF3B1 mutation was primarily accounted for by IPSS risk categorization., Conclusion: MDS-RS patients carrying SF3B1 mutations harbored a more severe iron overload and corresponding over-erythropoiesis. The better overall survival of SF3B1-mutated MDS-RS patients may be mainly due to the clustering of patients with lower risk disease in this group., (Copyright © 2016 Elsevier Ltd. All rights reserved.)