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Few prospective studies have examined posttransplant chimeric antigen receptor (CAR) T cell infusion as candidates for front-line consolidation therapy for high-risk multiple myeloma (MM) patients. This single-arm exploratory clinical trial is the first to evaluate the safety and efficacy of sequential anti-CD19 and anti-BCMA CAR-T cell infusion, followed by lenalidomide maintenance after autologous stem cell transplantation (ASCT), in 10 high-risk newly diagnosed multiple myeloma (NDMM) patients. The treatment was generally well tolerated, with hematologic toxicities being the most common grade 3 or higher adverse events. All patients had cytokine release syndrome (CRS), which was grade 1 in 5 patients (50%) and grade 2 in 5 patients (50%). No neurotoxicity was observed after CAR-T cell infusion. The overall response rate was 100%, with the best response being 90% for a stringent complete response (sCR), and 10% for a complete response (CR). At a median follow-up of 42 (36-49) months, seven (70%) of 10 patients showed sustained minimal residual disease (MRD) negativity for more than 2 years. The median progression-free survival (PFS) and overall survival (OS) were not reached. Although the sample size was small and there was a lack of control in this single-arm study, the clinical benefits observed warrant ongoing randomized controlled trials.

ETO2 is a nuclear co-repressor, which plays a critical role in the regulation of the cell cycle, self-renewal capacity, and differentiation of hematopoietic progenitor cells. We identified novel fusion transcripts involving ETO2 and CTCF by RNA-seq in a multiple relapsed AML case. The CTCF-ETO2 and ETO2-CTCF chimeric genes were validated by RT-PCR and Sanger sequencing. In addition, both transcripts apparently promoted cell proliferation via JAK/STAT3 pathway that is sensitive to STAT3 inhibitors. The novel fusions may have prognostic value and pathogenic mechanisms in acute myeloid leukemia.

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm defined by the presence of t(9;22)(q34;q11.2)/BCR::ABL1. Additional chromosomal abnormalities play an important role in the progression to CML. However, the additional fusion gene was rarely reported such as CBFB::MYH11. In this report, we described two cases of the co-occurrence of BCR::ABL1 and SET::NUP214 in CML-BP for the first time, which is associated with poor outcomes during tyrosine kinase inhibitor (TKI) treatment. Meanwhile, we retrospectively analyzed SET::NUP214 fusion transcript of the two cases at initial diagnosis of the CML chronic phase by quantitative RT-PCR, and detected at a ratio of 1.63% and 1.50%, respectively. SET::NUP214 may promote disease progression during the transformation of CML. This study highlights the importance of extended molecular testing at the initial diagnosis of CML-CP at TKI resistance and/or disease transformation.

About 5 per cent of follicular lymphoma (FL) cases are double‐hit (DH) lymphomas. Double‐hit follicular lymphoma (DHFL) cell lines can improve our understanding and drug development on FL. But there are only few DHFL cell lines. Here, we established a new MYC/BCL2 DHFL cell line, FL‐SJC. The cells were obtained from the hydrothorax of a patient with MYC/BCL2 DHFL and cultured for 140 passages in vitro. FL‐SJC cells demonstrated CD19++, CD20+, CD22++, HLA‐DR+, CD10+, CD38+, Lambda+ CD23‐, CD5‐ and Kappa‐. The chromosome karyotypic analysis confirmed the co‐existence of t(8;22)(q24;q11) and t(14;18)(q32;q21), as well as additional abnormalities involving chromosomes 2 and 3. Fluorescence in situ hybridization analysis (FISH) showed IGH/BCL2 fusion gene and the MYC rearrangement. In addition, the FL‐SJC cells displayed KMT2D/MLL2 and CREBBP gene mutations. After subcutaneous inoculation of FL‐SJC cells, the SCID mice developed solid tumour masses within 6‐8 weeks. FL‐SJC cells were proven to be free of Epstein‐Barr (EB) virus infection and be multidrug‐resistant. In a conclusion, the FL‐SJC cell line has been identified as a novel MYC/BCL2 double‐hit follicular lymphoma that can be used as a potentially available tool for the clinical and basic research, together with the drug development for MYC/BCL2 DHFL.

Myeloproliferative neoplasm (MPN) with PCM1-JAK2 rearrangement is a rare disease with poor prognosis and lacks uniform treatment guidelines. Several studies confirmed the efficacy of ruxolitinib in hematological malignancies with PCM1-JAK2 fusion, but the efficacy is variable. Here, we report two patients diagnosed with MPN with PCM1-JAK2 fusion who were treated with ruxolitinib-based regimen, including the first case of ruxolitinib combined with pegylated interferon (Peg-IFN), and we conduct a literature review. We found that ruxolitinib combined with Peg-IFN is an effective treatment option in the case of poor efficacy of ruxolitinib monotherapy.

Genetic variants have been identified in the majority of myelodysplastic syndromes (MDS) patients and have considerably influenced the diagnosis, classification, risk stratification and treatment of MDS. To explore the prognostic significance of genomic variants and build a new prognostic scoring model, we performed next-generation sequencing of 51 known genes in 499 Chinese patients with MDS. Ultimately, the

The prognostic significance of rare BCR-ABL1 transcripts is uncertain in the tyrosine kinase inhibitor (TKI) era. In this retrospective study, 40 (1.7%) patients with rare BCR-ABL1 transcripts were identified from a cohort of 2331 chronic myeloid leukemia (CML) patients; 4 types of rare transcripts were identified, including e1a2 (0.9%), e19a2 (0.4%), e13a3 (0.1%), and e14a3 (0.3%). Compared to patients with the typical transcript, those with the e1a2 transcript had an inferior response to TKIs and a worse outcome. Patients with the e19a2 transcript had a high rate of early optimal response to TKIs, but most of them later lost the complete cytogenetic response (CCyR) due to BCR-ABL1 mutations, resulting in a poor prognosis. Patients with the e13a3/e14a3 transcript responded well to TKIs and had a good outcome. These findings indicate that the type of BCR-ABL1 transcript should be considered when determining the treatment for CML patients in the TKI era.

Background: The ETV6-NTRK3 fusion transcript has been found to recurrently identified in both solid tumors and leukemias. It has attracted a lot of interest for the clinical targeted therapy and genetic features in ETV6-NTRK3 positive solid tumors. While the t(12;15)(p13;q25)/ETV6-NTRK3 is a rare genetic aberration in hematologic malignancies at a low frequency of ≤1%. An accumulation of reported cases would be needed to discuss clinical and cytogenetic characteristics of the important entity. Therefore, it is useful to report every case for clinical implication of prognosis or therapy. Case presentation: We report the case of a previously healthy 30-year-old female, who was diagnosed as acute myeloid leukemia (AML) and presented with chemoresistance and short survival. The patient was treated with four cycles of chemotherapy but failed to achieve remission. Then the patient underwent a salvage haploidentical stem cell transplantation. Unfortunately, she worsened within 1 month and died of the refractory leukemia 35 days after transplantation. ETV6-NTRK3 rearrangement was revealed by RNA sequencing but the chromosomal translocation t(12;15)(p13;q25) was cryptic by conventional karyotype analysis. We review the literature and find that the ETV6-NTRK3 fusion transcript is associated with cryptic karyotype, trisomy 8, aggressive and poor prognosis in hematologic malignancy. The clinical and laboratory characteristics of ETV6-NTRK3 positive hematologic malignancies are different from those of solid tumors. Nevertheless, tropomyosin receptor kinase (TRK) inhibitor has powerful anti-tumor activity in patients with TRK fusion–driven cancers, regardless of the tumor type. Conclusions: We demonstrated that TRK inhibitor larotrectinib is an effective treatment on the primary bone marrow (BM) cells derived from the patient described here with ETV6-NTRK3 positive AML. Our report stresses the importance of screening for ETV6-NTRK3 fusion transcript in newly diagnosed leukemias and clinical treatment of TRK inhibitor in hematologic malignancies.

Acute promyelocytic leukemia (APL) is a unique disease entity in acute myeloid leukemia, characterized by PML-RARA fusion gene, which is generated by chromosomal translocation t(15;17)(q24;q21). We identified TNRC18-RARA as novel RARA fusion in resembling APL. Our study highlights the importance of combining multiple molecular techniques to characterize and optimally manage APL lacking classic t(15;17)(q24;q12)/PML-RARA fusion.

Background ETO2 is a nuclear co-repressor, which plays a critical role in the regulation of the cell cycle, self-renewal capacity, and differentiation of hematopoietic progenitor cells. Methods We identified novel fusion transcripts involving ETO2 and CTCF by RNA-seq in a post-transplant relapsed case. Results The CTCF-ETO2 and ETO2-CTCF chimeric genes were validated by RT-PCR and Sanger sequencing. In addition, both transcripts apparently promoted cell proliferation which is beneficial to tumorigenesis. Conclusion The novel fusions may have prognostic value and pathogenic mechanisms in acute myeloid leukemia.

We retrospectively evaluated the efficacy and safety of dasatinib among 48 Chinese patients with chronic phase chronic myeloid leukaemia. The proportions of patients achieving the optimal molecular responses at 3, 6, and 12 months, a major molecular response (MMR) rate and a complete cytogenetic response (CCyR) rate were 87.0, 87.0, 72.2, 45.8, and 72.7% for patients with dasatinib as second-line therapy, and 34.8, 34.8, 33.3, 20.8, and 46.2% as third-line therapy, respectively. A BCR-ABL1 transcript level on the International Scale (BCR-ABL1IS) of ≤10% at the initiation of ­dasatinib treatment was found to be associated with a higher probability of achieving MMR. Among patients with a ­BCR-ABL1IS higher than 10% at initiation of dasatinib treatment, dasatinib showed better performance as a second-line therapy than as a third-line therapy. The patients who achieved an optimal molecular response at 3 months had a superior cumulative incidence of MMR and CCyR compared with patients who failed to achieve such a response. Dasatinib induced considerable responses as a second-line treatment, especially in patients with a BCR-ABL1IS ≤10% at initiation of treatment, whereas the efficacy was limited in patients receiving third-line therapy with a BCR-ABL1IS >10% at the initiation of treatment.

Isochromosome 20q- (i(20q-)), as a rare reproducible chromosomal anomaly formed on the basis of 20q-, has not been commonly reported. Due to the rarity of this karyotypic anomaly, the bone marrow morphological characteristics of the patients with i(20q-) have not been clarified until now. In this study, the bone marrow cell morphology from MDS patients with isolated i(20q-), isolated 20q-, and normal karyotype was retrospectively compared and statistically analyzed. The results indicated that the isolated i(20q-) was mostly detected in MDS-MLD patients. The frequency and proportion dysplasia of cytoplasmic vacuolization in erythoid cells and small or unusually large size in myeloid cells of isolated i(20q-) MDS patients were significantly higher than those of normal karyotype MDS patients respectively (P

t(12;22)(p13;q12) is a rare but recurrent chromosomal abnormality involving the ETS transcription factor ETV6 and meningioma 1 (MN1) genes. In this study, we analyzed the clinical, cytogenetic, and molecular features of five new patients with the t(12;22)/MN1-EVT6 who presented with acute myeloid leukemia or chronic myelomonocytic leukemia. We subsequently reviewed the literature and identified seven additional cases reported with t(12;22)/MN1-EVT6. Our data suggest that neoplasms carrying the t(12;22)/MN1-ETV6, although rare, can commonly present as myeloid neoplasms at the initial diagnosis, including acute myeloid leukemia (n = 8), myelodysplastic syndrome (n = 2), and myelodysplastic/myeloproliferative neoplasms (n = 2). There were five men and seven women with a median age of 43 years (range, 15-63 years) at initial diagnosis. Cytogenetics revealed t(12;22) as the sole abnormality in five patients, with the remaining seven patients harboring additional chromosomal aberrations. Of the five patients who received known therapy regimens, all of them had poor response to the idarubicin/mitoxantrone + cytarabine regimen. Of the seven patients with follow-up information, six patients died with a median overall survival time of only 5 months (range, 1-12 months) after the emergence of t(12;22). In summary, patients with t(12;22) are frequently associated with myeloid neoplasms, poor response to chemotherapy, and inferior outcome.

High frequency of RUNX1 mutation in myelodysplastic syndrome patients with whole-arm translocation of der(1;7)(q10;p10)

Background Multiple myeloma (MM) is a heterogenous plasma cell malignancy. About 30-40% of newly diagnosed and 20-60% of relapsed/refractory MM patients carry 1q21 amplification worldwide, a high-risk indicator for poor prognosis in RRMM. Different BCL-2 family anti-death proteins play important roles in MM survival and drug resistance. High expression of BCL-2 due to t (11;14) renders cell vulnerability to BCL-2 antagonist, however, patients carrying other genetic abnormality including 1q21 amplification have limited response to the newly emerged treatment choice. With MCL-1 upregulation accompanied with 1q21 amplification, we tested whether BCL-2 antagonist combined with IMiDs (immunomodulatory imide drugs), improves cell killing in high-risk MM patient models, including those resistant to bortezomib and lenalidomide. For that aim, we studied APG-2575, a novel and potent BCL-2 inhibitor developed by Ascentage Pharma Group and it is currently in clinical trials for hematologic malignances, including MM. Methods 1. Cells were treated with APG-2575 single agent or in combination with lenalidomide; 2. Cell line viability was assessed by CellTiter-Glo (CTG) assay; 3. Flow cytometry analysis was used to detect CD138+ cell surface marker in primary cells derived from MM patients; 4. Western blot analysis for BCL-2 family and IMiD signaling proteins. Results We first determined the cell sensitivity of APG-2575 as a single agent in a panel of MM cell lines, and as expected, those carrying t (11;14) were very sensitive to APG-2575, with low IC50 values ranging 7-23 nM. The IC50 values for cells carrying other genetic markers were greater than 5-10 μM. We then evaluated cell-death inducing activity of APG-2575 in MM patient-derived primary cells ex vivo, which were freshly prepared from patients' bone marrow aspirates. Primary cells were treated with APG-2575 or ABT-199 (venetoclax) for 18-24 hours, and the loss of CD138 surface marker was used to quantify cell death. As shown in Figure 1a, APG-2575 induced cell death (CD138+ loss) in a dose-dependent manner, and significant cell death was observed at 0.37-3.3 μM of APG-2575, indicating primary cells more sensitive than MM cell lines. Interestingly, the sensitivity to APG-2575 is similar in primary MM cells with or without 1q21 amplification. Since moderate cell death inducing activity was observed in MM cells when APG-2575 used as a single agent, we combined APG-2575 with lenalidomide. Cell death was increased in the combination groups compared with single agent, and it was dose-dependent (Figure 1b).Similar enhanced antiproliferative activity was confirmed in RPMI 8226 cell line, which carries 1q21 amplification (Figure 1c). We furthered to understand the mechanism of action (MoA) of this combination. In Figure 1d, Western blot analysis of RPMI 8226 cell line revealed that IKZF1 and IKZF3 proteins from the NF-KB pathway were downregulated by lenalidomide. And the decrease of MCL-1 protein and the strong induction of pro-death protein BAK were evident in the combination group of APG-2575 and lenalidomide, which helps to illustrate MoA underlying the synergistic effect of APG-2575 and lenalidomide in MM models. Conclusions In both cell lines and primary samples derived from MM patients, APG-2575 demonstrates cell death inducing activity as a single agent, and enhanced/synergistic effects when it combines with lenalidomide in RRMM resistant to lenalidomide and bortezomib. The combination decreases IKZF1, IKZF3 and MCL-1 proteins, and upregulates pro-death protein BAK, thus providing a strong rationale to combine BCL-2 inhibitor and lenalidomide to treat high-risk patient populations carrying 1q21 amplification. Disclosures FU: Ascentage Pharma (SuZhou) Co., Ltd: Other: research agreement contract . Yin:Ascentage Pharma (SuZhou) Co., Ltd: Current Employment. Mao:Ascentage Pharma (SuZhou) Co., Ltd: Current Employment. Deng:Ascentage Pharma (SuZhou) Co., Ltd: Current Employment. Fang:Ascentage Pharma (SuZhou) Co., Ltd: Current Employment. Yang:Ascentage Pharma (SuZhou) Co., Ltd: Current Employment, Current equity holder in publicly-traded company, Other: Leadership and other ownership interests. Zhai:Ascentage Pharma (SuZhou) Co., Ltd: Current Employment, Current equity holder in publicly-traded company, Other: Leadership and other ownership interests.

The glutamine amino acid transporter solute carrier family 38 member 1 (SLC38A1) is associated with the occurrence and progression of solid tumors. However, it has not yet been assessed in patients with hematologic malignancy. Herein, we investigated SLC38A1 expression and explored its clinical implications in acute myeloid leukemia (AML). The results showed that patients with high SLC38A1 expression had a lower mutation rate of NPM1 gene and higher incidence of adverse-risk karyotype (p = 0.0010 and 0.0051, respectively). Patients with a high level of SLC38A1 expression presented significantly shorter overall survival in whole-cohort, chemotherapy-only, and non-inv(16) AML (p = 0.0049, 0.0247, and 0.0005 respectively). Moreover, both univariate and multivariate analyses showed that high SLC38A1 expression was an independent unfavorable prognostic biomarker for AML (p = 0.0057 and 0.0483, respectively). In summary, our study revealed SLC38A1 as a valuable prognostic and predictive marker for AML. Further, glutamine transporter SLC38A1 might serve as a potential target for the development of novel therapeutic drugs in the treatment of AML.

Acute promyelocytic leukemia (APL) is a unique disease entity in acute myeloid leukemia (AML), characterized by the expansion of leukemic cell block at the promyelocytic stage. The vast majority of APL patients bear t(15;17)(q24;q21) involving the promyelocytic leukemia ( PML ) gene at chromosome

Deletion of the long arm of chromosome 20 is a common abnormality underlying hematological malignancy. We analyzed 21 patients with hematologic diseases confirmed to carry the del(20q) by conventional cytogenetics and fluorescence in situ hybridization using microarray comparative genomic hybridization (aCGH). Seventeen patients were positive for del(20q), but this deletion was not detected in four patients. All deletions detected were interstitial of which continuous deletions were seen in 12 patients and discrete deletions in five. Three commonly deleted regions (CDRs) and two commonly retained regions (CRRs) were defined: CDR1 spanning 3.05Mb (34560497-37608229) within 20q11.23, CDR2 spanning 1.76Mb (37851501-39615698) within 20q12, CDR3 spanning 116Kb (48120412-48236791) within 20q13.13, CRR1 spanning 1.1Mb (29374726-30428250) within 20q11.21, and CRR2 spanning 2.5Mb (60484668-62963548) within 20q13.33. Duplications of retained regions (20q11.21) were found in five cases with similar erythroid hyperplasia (2 M6, 3 MDS). Moreover, duplication of 20p13-p11.21 was also found in two cases with M6. Using the CDRs and CRRs, we identified the candidate genes we searched for using the UCSC Genome Browser. Our data suggest that aCGH analysis is useful for more precisely defining breakpoints on 20q. Further work is required to identify candidate pathogenic genes within these CDRs and CRRs.

Chronic myeloid leukemia (CML) is rare among children and adolescents. The early molecular response (EMR) is an important prognostic significance for adult CML patients. This study explored the impact of EMR on the prognosis in 40 children and adolescents with CML-CP treated with imatinib (IM). Our results showed that a high proportion of patients failed to achieve the BCR-ABL1/ABL1 International Scale (IS) ≤ 10% at 3 months. Children with a BCR-ABL1/ABL1 ≤ 10% at 3 months and 1% at 6 months increased the rate of achieving complete cytogenetic response (CCyR) and/or major molecular response (MMR) at 12 months compared to those with BCR-ABL1/ABL1 10%. With a median follow-up of 42 months, patients with BCR-ABL1/ABL1 ≤ 10% showed a better 4-year event-free survival (EFS). In summary, achieving BCR-ABL1/ABL1 IS ≤10% at 3 months and1% at 6 months would increase the possibility of achieving MMR, CCyR at 12 months and had a better 4-year EFS. EMR is a reliable prognosticator for young CML patients treated with IM.

The vitamin D (1,25-dihydroxyvitamin D3) receptor (VDR) gene encodes a protein that functions in the transcriptional regulation of vitamin D-responsive genes and plays a role in innate immunity and adaptive immune responses. In this study, we investigated the relationship between VDR polymorphisms (BsmI, ApaI, and TaqI) and primary biliary cirrhosis (PBC) risk. We conducted an overall meta-analysis and subgroup meta-analysis based on ethnicity that included a total of 6 eligible studies (672 cases and 1148 controls). We detected no significant PBC risk variation for all genetic models in the overall analysis and in the subgroup analysis based on ethnicity for the BsmI polymorphism. For the ApaI polymorphism, significant associations were observed in the overall analysis as well as in the Asian subgroup. Furthermore, in the subgroup analysis based on ethnicity, a significant association was observed in the Caucasian subgroup but not in the Asian subgroup for the TaqI polymorphism. Based on the results of our meta-analysis, the VDR BsmI polymorphism may not be associated with PBC risk, while the VDR ApaI polymorphism is likely associated with PBC risk, particularly in Asians. The VDR TaqI polymorphism may be associated with PBC risk in Caucasians.

To report on clinical and laboratory features of myeloid neoplasms with double del(20q).Cytogenetic examination of bone marrow was performed on 13 cases of myeloid neophasms with double del(20q) after 24 hours of cell culture. R-banding was used to analyze the karyotypes. Interphase fluorescence in situ hybridization (FISH) was performed using dual-color probes for 20q11/20q12.Double del(20q) was found to be the sole abnormality in 9 cases, double del(20q) and trisomy 9 was found in 1 case, trisomy del(20q) was found in 1 case, and sole del(20q) clone and double del(20q) clone were found to coexist in 2 cases. In 10 cases, interphase FISH showed one green and one red signal in cells with del(20q), which indicated deletion of both 20q11 and 20q12. Immunophenotyping of the leukemia cells showed positiveness for CD13 and/or CD33, CD117 in all 9 cases. Among these, co-expression of CD34 and/or HLA-DR was found in 6 cases, and coexpression of CD3 and CD7 was found in 1 case. Of the 13 cases, there were one AML-M6, nine MDS, one pure amegalokaryocye aplastic thrombocytopenia, one with normal morphology of bone marrow, and one undetermined due to dilution of the bone marrow by blood. Cytopenia were found in all cases. 9 of 13 cases died, and 4 survived with a median survival of 9 months.Double del(20q) is a rare but recurrent chromosomal abnormality derived from del(20q). It has unique clinical and laboratory features, and the prognosis is poor.

Myelodysplastic syndromes (MDS) are clonal disorders of hematopoietic stem/progenitor cells. As bone marrow cells are extremely diverse in these disorders, the origin and evolution of MDS clones are difficult to identify and trace. Cellular dysplasia is a distinct morphologic feature; however, whether the dysplastic cells represent abnormal clones or only nonspecific superficial phenomena remains to be clarified. To address this question, 97 patients were examined for dysplasia features, among them bone marrow slides of 16 patients with chromosomal abnormalities were subjected to fluorescence in situ hybridization (FISH) to determine the karyotype of these dysplastic cells. Furthermore, the emerging frequencies of abnormal karyotypes in various differentiated stages of each lineage were also evaluated by a combination of morphological evaluation and FISH karyotyping. Our results indicate that the overall percentage of dysplastic cells does not differ significantly among the WHO subtypes, while the megakaryoid lineage presents the most frequent dysplasia in all subtypes. A positive correlation between dysplastic cells and FISH-detectable abnormal clones was observed, but the dysplastic morphology was not a specific feature of FISH-detectable abnormal clones. FISH-detectable abnormal clones can differentiate into mature granulocytes and erythrocytes, in coexistence with cells originating from the normal clones.

The clinical and hematological characteristics and the prognostic significance of del(20q) were investigated in a consecutive series of 213 myeloid malignancies. In the analyses, the cases were divided into three subgroups according to diagnosis or four subgroups according to cytogenetic data. Patients in the myeloproliferative neoplasms subgroup had high WBCs and platelet counts at initial diagnosis. The del(20q) occurred predominantly in older men. Sole del(20q) was observed most often in myelodysplastic syndromes, while del(20q) as a part of complex karyotypes was observed predominantly in acute myeloid leukemia. The most frequent additional abnormalities accompanying del(20q) were -5/del(5q), -7/del(7q) and +8; t(20;21)(q11;q11) and double del(20q) were two rare but recurrent abnormalities secondary to del(20q). In all types of diseases, patients with a sole del(20q) had a favorable prognosis. The presence of any additional abnormality with del(20q) had an unfavorable outcome. Patients with i(20q) had an unfavorable prognosis. Patients with the minor del(20q) clone had a better median survival than those with the major del(20q) clone.

Background Myeloproliferative neoplasms (MPNs), typically defined by myeloid proliferation and eosinophilia, and are only rarely caused by platelet-derived growth factor receptor beta (PDGFRB) gene rearrangements. Case presentation Here, we report a unique case of MPN that is negative for eosinophilia and characterized by a novel PDGFRB rearrangement. After cytogenetic analysis revealed a karyotype of t(5;17) (q32;q11), we used fluorescence in situ hybridization to specifically identify the PDGFRB gene at 5q31-q33 as the gene that had been translocated. Subsequently, RNA sequencing identified a new MYO18A-PDGFRB gene fusion. This fusion presented a previously undescribed breakpoint composed of exon 37 of MYO18A and exon 13 of PDGFRB. Furthermore, both RT-PCR and Bi-directional Sanger sequencing confirmed this out-of-frame fusion. Interestingly, we simultaneously identified the presence of another three PDGFRB transcripts, all of which were in-frame fusions. After treating the patient with imatinib, the t(5;17) translocation was no longer detected by conventional cytogenetics or by FISH, and at the time of the last follow-up, the patient had been in complete remission for 26 months. Conclusion We prove that MYO18A-PDGFRB fusions are recurrent genetic aberrations involved in MPNs, and identify multiple fusion transcripts with novel breakpoints.

Membrane-proximal and truncated mutations of colony-stimulating factor 3 receptor (CSF3R) are frequently found in chronic neutrophilic leukemia (CNL) and atypical chronic myeloid leukemia (aCML). However, rearrangement involving CSF3R in hematological neoplasms has not been reported. Here, we report a case of a 21-year-old female diagnosed as aCML with t(1;9)(p34;q34) who presented a CSF3R rearrangement. First, RNA sequencing identified a novel fusion transcript involving exon 17 of CSF3R and exon 50 of non-erythrocytic-1-spectrin-alpha (SPTAN1). Subsequent reverse transcription-polymerase chain reaction (RT-PCR) and bidirectional Sanger sequencing confirmed the in-frame fusion. The breakpoint was located at the C-terminus of CSF3R, suggesting a pattern of truncation mutation of CSF3R. Unexpectedly, the patient failed to achieve a complete hematological response following the SRC kinase inhibitor dasatinib therapy, which has been reported to effectively inhibit truncated forms of CSF3R. The patient accepted allogeneic hematopoietic stem cell transplantation (HSCT) and currently remains in a good state. In conclusion, this report is the first to identify a fusion involving CSF3R and SPTAN1 in aCML with t(1;9)(p34;q34).