Non-canonical BRAF variants and rearrangements in hairy cell leukemia

Hairy cell leukemia(HCL)is an uncommon mature B-cell malignancy characterized by a typical morphology,immunophenotype,and clinical profile.The vast majority of HCL patients harbor the canonical BRAF V600E mutation which has become a rationalized target of the subsequently deregulated RAS-RAF-MEK-MAPK signaling pathway in HCL patients who have relapsed or who are refractory to front-line therapy.However,several HCL patients with a classical phenotype display non-canonical BRAF mutations or rearrangements.These include sequence variants within alternative exons and an oncogenic fusion with the IGH gene.Care must be taken in the molecular diagnostic work-up of patients with typical HCL but without the BRAF V600E to include investigation of these uncommon mechanisms.Identification,functional characterization,and reporting of further such patients is likely to provide insights into the pathogenesis of HCL and enable rational selection of targeted inhibitors in such patients if required.

Hairy cell leukemia presenting as multiple discrete hepatic lesions

The involvement of hairy cell leukemia in the liver is in the form of portal and sinusoidal cellular infiltration. Here we describe the first case of hepatic hairy cell leukemia presenting as multiple discrete lesions,which was treated successfully.We suggest that in the inves- tigation of discrete hepatic lesions in cases of cancer of unknown primary,hairy cell leukemia should be consid- ered.The excellent response of hairy cell leukemia to therapy highlights the need for such a consideration.

Gossypol acetic acid regulates leukemia stem cells by degrading LRPPRC via inhibiting IL-6/JAK1/STAT3 signaling or resulting mitochondrial dysfunction

BACKGROUND Leukemia stem cells(LSCs)are found to be one of the main factors contributing to poor therapeutic effects in acute myeloid leukemia(AML),as they are protected by the bone marrow microenvironment(BMM)against conventional therapies.Gossypol acetic acid(GAA),which is extracted from the seeds of cotton plants,exerts anti-tumor roles in several types of cancer and has been reported to induce apoptosis of LSCs by inhibiting Bcl2.AIM To investigate the exact roles of GAA in regulating LSCs under different microenvironments and the exact mechanism.METHODS In this study,LSCs were magnetically sorted from AML cell lines and the CD34+CD38-population was obtained.The expression of leucine-rich pentatricopeptide repeat-containing protein(LRPPRC)and forkhead box M1(FOXM1)was evaluated in LSCs,and the effects of GAA on malignancies and mitochondrial RESULTS LRPPRC was found to be upregulated,and GAA inhibited cell proliferation by degrading LRPPRC.GAA induced LRPPRC degradation and inhibited the activation of interleukin 6(IL-6)/janus kinase(JAK)1/signal transducer and activator of transcription(STAT)3 signaling,enhancing chemosensitivity in LSCs against conventional chemotherapies,including L-Asparaginase,Dexamethasone,and cytarabine.GAA was also found to downregulate FOXM1 indirectly by regulating LRPPRC.Furthermore,GAA induced reactive oxygen species accumulation,disturbed mitochondrial homeostasis,and caused mitochondrial dysfunction.By inhibiting IL-6/JAK1/STAT3 signaling via degrading LRPPRC,GAA resulted in the elimination of LSCs.Meanwhile,GAA induced oxidative stress and subsequent cell damage by causing mitochondrial damage.CONCLUSION Taken together,the results indicate that GAA might overcome the BMM protective effect and be considered as a novel and effective combination therapy for AML.

THE ULTRASTRUCTURAL STUDY OF NON－HODGKIN＇S LYMPHOMA CELL，CHRONIC LYMPHOCYTIC AND HAIRY CELL LEUKEMIA

Non-Hodgkin’s lymphoma cell leukemia (NHLCL),chronic lymphocytic leukemia (CLL) and hairy cell leukemia (HLC) are the diseases very similar to each other. The differential diagnosis is very difficult,especially when there are small lymphoid cells in Periphcral blood and bone marrow under light microscope. We have observed 34 cases with electron microscope. The studies were correlated with clinical manifestation, cytology, pathology and immunologic histochemistry. Ultrastructural features strongly indicated the difference in three various diseases, although all the immunologic markers showed B-cell type.It is concluded that electron microscopic examination is of a definite significance in the diaguosis and successful treatment.

Allogeneic stem cell transplantation in the treatment of acute myeloid leukemia: An overview of obstacles and opportunities

As an important treatment for acute myeloid leukemia, allogeneic hematopoietic stem cell transplantation(allo-HSCT) plays an important role in reducing relapse and improving long-term survival. With rapid advancements in basic research in molecular biology and immunology and with deepening understanding of the biological characteristics of hematopoietic stem cells, allo-HSCT has been widely applied in clinical practice. During allo-HSCT, preconditioning, the donor, and the source of stem cells can be tailored to the patient’s conditions, greatly broadening the indications for HSCT, with clear survival benefits. However, the risks associated with allo-HSCT remain high, i.e. hematopoietic reconstitution failure, delayed immune reconstitution, graft-versus-host disease, and posttransplant relapse, which are bottlenecks for further improvements in allo-HSCT efficacy and have become hot topics in the field of HSCT. Other bottlenecks recognized in the current treatment of individuals diagnosed with acute myeloid leukemia and subjected to allo-HSCT include the selection of the most appropriate conditioning regimen and post-transplantation management. In this paper, we reviewed the progress of relevant research regarding these aspects.

Unusual presentation of gastric cancer during treatment of hairy cell leukemia:Exploring the etiological basis of this rare phenomenon

Hairy cell leukemia(HCL)is a rare B-cell lymphoproliferative disorder.Patients typically present with cytopenia and splenomegaly.We describe the case of a 78-year-old patient with refractory HCL who acutely developed a cystic lesion on the back while receiving moxetumomab pasudotox therapy.Biopsy of the lesion revealed the presence of adenocarcinoma,which prompted a detailed evaluation resulting in a diagnosis of stage IV gastric cancer.Nevertheless,to establish any association between moxetumomab pasudotox therapy and secondary cancer development,a satisfactory number of studies need to be conducted.

Co-existing squamous cell carcinoma and chronic myelomonocytic leukemia with ASXL1 and EZH2 gene mutations:A case report

BACKGROUND Chronic myelomonocytic leukemia(CMML),a rare clonal hematopoietic stem cell disorder characterized by myelodysplastic syndrome and myeloproliferative neoplasms,has a generally poor prognosis,and easily progresses to acute myeloid leukemia.The simultaneous incidence of hematologic malignancies and solid tumors is extremely low,and CMML coinciding with lung malignancies is even rarer.Here,we report a case of CMML,with ASXL1 and EZH2 gene mutations,combined with non-small cell lung cancer(lung squamous cell carcinoma).CASE SUMMARY A 63-year-old male,suffering from toothache accompanied by coughing,sputum,and bloody sputum for three months,was given a blood test after experiencing continuous bleeding resulting from a tooth extraction at a local hospital.Based on morphological results,the patient was diagnosed with CMML and bronchoscopy was performed in situ to confirm the diagnosis of squamous cell carcinoma in the lower lobe of the lung.After receiving azacitidine,programmed cell death protein 1,and platinum-based chemotherapy drugs,the patient developed severe myelosuppression and eventually fatal leukocyte stasis and dyspnea.CONCLUSION During the treatment and observation of CMML and be vigilant of the growth of multiple primary malignant tumors.

Bortezomib-Induced Bilateral Eye Swelling and Cutaneous Adverse Reaction in a Patient with Plasma Cell Leukemia—A Case Report

Bortezomib, a proteasome inhibitor, is an established therapy against plasma cell leukemia—a variant of plasma cell dyscrasias. Its most frequent side effects have been listed as peripheral neuropathy, neuropathic pain, thrombocytopenia, and gastrointestinal problems. Allergic skin reaction is a rarely documented side effect in patients receiving bortezomib-based chemotherapy. A combination therapy consisting of intravenous bortezomib, oral Revlimid tablets, and oral dexamethasone tablets has been prescribed for the patient after his recent diagnosis of plasma cell leukemia. While receiving his third treatment cycle, he developed an allergic reaction (skin rash) involving the neck, and wrists, and mild bilateral eye swelling. The infusion was stopped immediately and then ciprofloxacin ophthalmic solution and oral diphenhydramine 25 mg were prescribed to the patient with significant improvement in his clinical condition. He was temporarily taken off bortezomib. At a follow-up visit a week later, a significant improvement was noticed in his condition. Rash had reduced on neck and wrists, and eye swelling had reduced as well. As of the time of writing this case report, he has been temporarily taken off bortezomib, but other medications in the treatment regimen were continued as prescribed.

From Myeloma to Plasma Cell Leukemia, Persistent Inequalities

Multiple myeloma (MM) is both a complex and heterogeneous disease. Cytogenetic and molecular abnormalities lead to resistance to treatment and transformation to plasma cell leukemia, which is defined by the presence in circulating blood of plasma cells over 2 G/L, or more than 20% of leukocytes. It is an uncommon hematological malignancy with a poor prognosis. Against this backdrop, we report an observation of multiple myeloma transformed into plasma cell leukemia diagnosed at the Hôpital Principal de Dakar (HPD) that occurred on a 64-year-old man with a history of thyroidectomy followed for multiple myeloma presenting with Salmon et Durie stage IIIA and ISS stage I. Despite a marked improvement in management strategy, myeloma remains an almost invariably incurable disease. However, the development of genetic and molecular biomarkers is necessary to improve its prognosis.

Circ_0012152 Accelerates Acute Myeloid Leukemia Progression through the miR-652-3p/SOX4 Axis

Objective Acute myeloid leukemia(AML)is an aggressive hematological malignancy characterized by abnormal myeloid blast expansion.Recent studies have demonstrated that circular RNAs play a role in AML pathogenesis.In this study,we aimed to investigate the clinical significance of circ_0012152 in AML and elucidate its underlying molecular mechanism in the pathogenesis of this condition.Methods Circ_0012152 expression was detected by quantitative real-time polymerase chain reaction in samples obtained from 247 patients with AML and 40 healthy controls.A systematic analysis of clinical characteristics and prognostic factors was also conducted.Cell growth was assessed using the Cell Counting Kit-8(CCK-8)assay,and apoptosis and cell cycle progression were evaluated by flow cytometry.Moreover,RNA pull-down was performed to identify target microRNAs,and transcriptome RNA sequencing and bioinformatics analyses were utilized to identify downstream mRNA targets.Results Circ_0012152 was significantly upregulated in samples from patients with AML and served as an independent adverse prognostic factor for overall survival(OS)(hazard ratio:2.357;95%confidence interval 1.258–4.415).The circ_0012152 knockdown reduced cell growth,increased apoptosis,and inhibited cell cycle progression in AML cell lines.RNA pull-down and sequencing identified miR-652-3p as a target microRNA of circ_0012152.Cell growth inhibition by circ_0012152 knockdown was significantly relieved by miR-652-3p inhibitors.We suggested that miR-652-3p targeted SOX4,as the decrease in SOX4 expression resulting from circ_0012152 knockdown was upregulated by miR-652-3p inhibitors in AML cells.Conclusion Circ_0012152 is an independent poor prognostic factor for OS in AML,and it promotes AML cell growth by upregulating SOX4 through miR-652-3p.

The Role of Mitochondrial VDAC2 in the Survival and Proliferation of T-Cell Acute Lymphoblastic Leukemia Cells

Background: T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy with aberrant T-cell developmental arrest. Individuals with relapsed T-ALL have limited therapeutic alternatives and poor prognosis. The mitochondrial function is critical for the T-cell viability. The voltage-dependent anion channel 2 (VDAC2) in the mitochondrial outer membrane, interacts with pro-apoptotic BCL-2 proteins and mediates the apoptosis of several cancer cell lines. Objective: The aim of the current study is to explore the role of VDAC2 in T-ALL cell survival and proliferation. Methods: Publicly available datasets of RNA-seq results were analyzed for expression of VDAC isoforms and T-ALL cell lines were treated with a VDAC2 small molecular inhibitor erastin. A VDAC2 RNA interference (siRNA) was delivered to T-ALL cell lines using a retroviral vector. Functional assays were performed to investigate the VDAC2 siRNA impacts on cell proliferation, apoptosis and survival of T-ALL cells. Results: Our analysis found a high expression of VDAC2 mRNA in various T-ALL cell lines. Public datasets of T-ALL RNA-seq also showed that VDAC2 is highly expressed in T-ALL (116.2 ± 36.7), compared to control groups. Only two T-ALL cell lines showed sensitivity to erastin (20 μM) after 48 hours of incubation, including Jurkat (IC50 = 3.943 μM) and Molt4 (IC50 = 3.286 μM), while another two T-ALL cells (CUTLL1 and RPMI 8402) had unstable IC50. However, five T-ALL cell lines (LOUCY, CCRF-CEM, P12-ICHI, HPB-ALL, and PEER cells) showed resistance to erastin. On the contrary, all T-ALL cell lines genetically inhibited with VDAC2 siRNA led to more than 80% decrease in VDAC2 mRNA levels, and a Conclusion: VDAC2 is highly expressed in T-ALL cells. The inhibition of VDAC2 significantly decreased cell viability, increased apoptosis, reduced cell proliferation and caused cell cycle sub-G1 arrest of T-ALL cells.

Resveratrol-downregulated Phosphorylated Liver Kinase B1 Is Involved in Senescence of Acute Myeloid Leukemia Stem Cells

Summary： Senescence is an important obstacle to cancer development. Engaging a senescent response may be an effective way to cure acute myeloid leukemia （AML）. The aim of this study was to examine the effect of resveratrol-downregulated phosphorylated liver kinase B1 （pLKB1） on the senescence of acute myeloid leukemia （AML） stem cells. The protein expressions of pLKB 1 and Sirtuin 1 （SIRT1）, a regulator ofpLKB1, were measured in CD34＋CD38-KGla cells treated with resveratrol （40 μmol/L） or not by Western blotting. Senescence-related factors were examined, including p21 mRNA tested by real-time PCR, cell morphology by senescence-associated β-galactosidase （SA-β-gal） staining, cell pro- liferation by MTT assay and cell cycle by flow cytometry. Besides, apoptosis was flow cytometrically determined. The results showed that pLKB1 was highly expressed in CD34＋CD38- KGla cells, and resveratrol, which could downregulate pLKB1 through activation of SIRT1, induced senescence and apoptosis of CD34＋CD38- KGla cells. It was concluded that resveratrol-downregulated pLKB1 is in- volved in the senescence of AML stem cells.

Allogeneic hematopoietic stem cell transplantation for patients with acute leukemia

Objective： The purposes of this study were to assess the efficacy of allogeneic hematopoietic stem cell transplantation （HSCT） for acute leukemia （AL） and analyze the factors affecting the prognosis of these patients. Methods： The clinical and follow-up data of 93 AL patients （median age, 30 years） undergoing allogeneic HSCT in Xiangya Hospital over the past 12 years were collected, and the potential factors affecting the efficacy and prognosis of allogeneic HSCT patients were determined. Results： Hematopoietic reconstitution was achieved in 90 patients. At the last follow-up, the incidences of severe acute graft versus host disease （aGvHD） and extensive chronic GvHD （cGvHD） were 14.0% and 20.0%, the 3-year cumulative incidence of transplantation related mortality （TRM） and relapse rate were 16.8%±6.1% and 21.3%±6.7%, and the estimated 3-year overall survival （OS） and disease-free survival （DFS） of the patients were 64.6%±5.4% and 56.5%±5.5%, respectively. Univariate analysis indicated that age older than 40 years, HLA mismatch, and severe lung infection within the first 100 days after transplantation were risk factors for severe aGvHD, age older than 40 years, HLA mismatch, severe lung infection within the first 100 days after transplantation, and severe aGvHD were risk factors for TRM, high-risk AL and lack of cGvHD were risk factors for relapse （all P〈0.05）. Survival estimation showed that HLA mismatch, severe lung infection occurring within the first 100 days post-transplantation, high-risk AL severe aGvHD and lack of cGvHD were risk factors associated with poor prognosis （all P〈0.05）. Further multivariate analyses revealed that severe lung infection within the first 100 days post-transplantation, severe aGvHD and lack of cGvHD were independent risk factors for unfavorable outcomes （all P〈0.05）. Conclusions： Allogeneic HSCT can improve the DFS of AL patients, and severe lung infection within the first 100 days post-transplantation, severe aGvHD and lack of cGvHD are independent risk factors affecting the prognosis.

Murine models based on acute myeloid leukemia-initiating stem cells xenografting

Acute myeloid leukemia(AML) is an aggressive malignant disease defined by abnormal expansion of myeloid blasts. Despite recent advances in understanding AML pathogenesis and identifying their molecular subtypes based on somatic mutations, AML is still characterized by poor outcomes, with a 5-year survival rate of only 30%-40%, the majority of the patients dying due to AML relapse. Leukemia stem cells(LSC) are considered to be at the root of chemotherapeutic resistance and AML relapse. Although numerous studies have tried to better characterize LSCs in terms of surface and molecular markers, a specific marker of LSC has not been found, and still the most universally accepted phenotypic signature remains the surface antigens CD34+CD38- that is shared with normal hematopoietic stem cells. Animal models provides the means to investigate the factors responsible for leukemic transformation, the intrinsic differences between secondary post-myeloproliferative neoplasm AML and de novo AML, especially the signaling pathways involved in inflammation and hematopoiesis. However, AML proved to be one of the hematological malignancies that is difficult to engraft even in the most immunodeficient mice strains, and numerous ongoing attempts are focused to develop "humanized mice" that can support the engraftment of LSC. This present review is aiming to in-troduce the field of AML pathogenesis and the concept of LSC, to present the current knowledge on leukemic blasts surface markers and recent attempts to develop best AML animal models.

PATHOLOGICAL STUDIES ON THE ANTI－INVASIVE CHARACTER BY RECOMBINANT HUMAN INTERLEUKIN－6 GENE－TRANSFECTED MOUSE LEUKEMIA CELLS

Mouse FBL-3 erythroleukemia cells were transfected with recombinant human interleukin-6 (rhIL-6) gene and a clone secreting IL-6 was selected (i.e., FBL-3-IL-6+). The cell clone secreting IL-6 was inoculated into C57BL/6 mouse. The growth of tumors was observed and histologic analyses of the tumors in situ, liver, spleen and bone marrow were performed after inoculation. The mice inoculated with wild-type FBL-3 erythroleukemia cells were used as the control. The results showed that the later the tumor occurrence, the slower the tumor development,the lower the pathological changes degree and the longer the survival time in experimental group compared to that of the control. The results demonstrated that the inoculation of the FBL-3 cell clone secreting IL-6 can inhibit the invasion of leukemia cells, suggesting that the FBL-3-IL-6+ cells can he used as a vaccine to treat leukemia.

Study of Heat Shock Protein HSP90α，HSP70，HSP27 mRNA Expression in Human Acute Leukemia Cells

The expression of three heat shock proteins (HSPs)-HSP90, HSP70,HSP27 in cells obtained from 22 patients with leukemia, K562 erythroleukemia cell line, and normal blood cells was observed by means of RNA dot blot analysis.The results showed that the expression of the HSP27 gene was enhanced in 4 cases of acute lymphoid leukemia (ALL), 7 cases of acute nonlymphoid leukemia (ANLL) and 2 cases of myelodysplastic syndrome (MDS) as compared with that of the normal blood cells, yet there was no significant difference in the HSP27 expression between the ALL and ANLL cells. The expression of HSP70 in all the 5 ALL and ANLL patients was much lower than that of the normal subjects, except 1 case of ALL and 1 case of MDS, in which the expression was obviously enhanced. All the cases including 11 ANLL, 5 ALL and 1 MDS had higher HSP90α expression than the normal subjects. The enhanced expression of HSP90α in leukemia cells may be associated with the active and indefinite proliferation of leukemia cells. Our results also suggest that the high expression of the HSP27gene may not be confined to a specific type of acute leukemia.

ADVANCES IN THE STUDY ON LEUKEMIA STRAINS AND LEUKEMIA CELL LINES IN CHINA

The study and establishment of leukemia strains and leukemia cell lines have made great achievement in China.It has been extended from mice to rat model and related to explore human leukemia cell line and heterotransplantable tumor strains. The cellular types of leukemia strain have included Iymphocytic,tmyelocytic,ecythroleukmia and megakaryoblastic cell strain.

NRS2002 assesses nutritional status of leukemia patients undergoing hematopoietic stem cell transplantation

Objective： To discuss whether nutritional risk screening 2002 （NRS2002） is appropriate for nutritional risk screening for leukemia patients before and after hematopoietic stem cell transplantation （HSCT）, and whether there are risk differences in other conditions, such as age, gender and matching degree; to find the methods and indicators of nutritional risk screening for these patients before and after HSCT, in order to give timely intervention to guarantee the successful completion of the entire transplantation process. Methods： Nutritional risk of 99 leukemia patients was screened with NRS2002 before and after HSCT. The ^（2 test was applied to compare the risk differences between groups such as age, gender and matching degree, while the differences of other enumeration data, such as recent （1-3 months） weight loss, reduced food intake within one week and BMI, were compared by continuity correction. Results： Of the 99 leukemia patients, 22 cases （22.2 %） had nutritional risk before HSCT, while all patients had nutritional risk after ttSCT; there is no significant difference in nutritional risk between male and female, and patients of less than 30 years old, not-full matched, recent （1-3 months） weight loss, reduced food intake within a week or BMI 〈18.5 were more likely to have nutritional risk; and 77 cases （77.8%） had weight loss, among which 49 patients （63.6%） had more than 5% weight loss within one month. Conclusions= This study showed that leukemia patients should receive the nutritional risk screening conventionally before and after HSCT, and NRS2002 was only appropriate for nutritional risk screening before HSCT. More attention should be paid to the patients less than 30 years old or not-full matched. Weight change was one of the important nutritional indicators for patients after HSCT.

Identification and targeting leukemia stem cells: The path to the cure for acute myeloid leukemia

Accumulating evidence support the notion that acute myeloid leukemia(AML) is organized in a hierarchical system, originating from a special proportion of leukemia stem cells(LSC). Similar to their normal counterpart, hematopoietic stem cells(HSC), LSC possess selfrenewal capacity and are responsible for the continued growth and proliferation of the bulk of leukemia cells in the blood and bone marrow. It is believed that LSC are also the root cause for the treatment failure and relapse of AML because LSC are often resistant to chemotherapy. In the past decade, we have made significant advancement in identification and understanding the molecular biology of LSC, but it remains a daunting task to specifically targeting LSC, while sparing normalHSC. In this review, we will first provide a historical overview of the discovery of LSC, followed by a summary of identification and separation of LSC by either cell surface markers or functional assays. Next, the review will focus on the current, various strategies for eradicating LSC. Finally, we will highlight future directions and challenges ahead of our ultimate goal for the cure of AML by targeting LSC.

A novel mouse model of adult T-cell leukemia cell invasion into the spinal cord

Adult T-cell leukemia( ATL) is a mature T-cell malignancy caused by human T-cell leukemia virus type I infection, and 10%-25% of patients show central nervous system( CNS) involvement. CNS involvement significantly reduces survival and there are no effective treatments for CNS involvement. Therefore, an appropriate animal model is required to evaluate the inhibitory effects of novel drugs on the progression of ATL with CNS involvement. Here, we established a mouse model of ATL with CNS involvement using NOD.Cg-Prkdc~ (scid) Il2 rg ^(tm1Wjl)/SzJ mice inoculated with ATL cells intramuscularly in the postauricular region, and these mice showed paraparesis. Of the 10 mice inoculated with ATL cells intramuscularly(I.M.) at 5 weeks of age, 8(80%) showed paraparesis, whereas none of the 10 mice inoculated with ATL cells subcutaneously(S.C.) showed paraparesis. In the I.M. group, PCR detected HTLV-1-specific genes in the thoracic and lumbar vertebrae; however, in the S.C. group, the vertebrae were negative for HTLV-1 genes. Histological analysis revealed a particularly high incidence of tumors, characterized by accumulation of the injected cells, in the thoracic vertebrae of mice in the I.M. group. Tumor cell infiltration was relatively high in the bone marrow. Spinal cord compression caused by invasion of the tumor mass outside the pia mater was observed in the thoracic vertebrae of the spinal cord. In conclusion, we have reported a mouse model of tumor growth with paraparesis that may be used to assess novel therapeutic agents for ATL with CNS involvement.