Safety and efficacy of flumatinib as later-line therapy in patients with chronic myeloid leukemia.

To evaluate the efficacy and safety of flumatinib in the later-line treatment of Chinese patients with Philadelphia chromosome-positive chronic-phase chronic myeloid leukemia (CP-CML previously treated with tyrosine kinase inhibitors (TKIs). Patients with CML-CP were evaluated for the probabilities of responses including complete hematologic response (CHR), cytogenetic response, and molecular response (MR) and adverse events (AEs) after the later-line flumatinib therapy. Of 336 enrolled patients with median age 50 years, median duration of treatment with flumatinib was 11.04 (2-25.23) months. Patients who achieved clinical responses at baseline showed maintenance of CHR, complete cytogenetic response (CCyR)/2-log molecular response (MR2), major molecular response (MMR), and 4-log molecular response or deep molecular response (MR4/DMR) in 100%, 98.9%, 98.6%, and 92.9% patients, respectively. CHR, CCyR/MR2, MMR, and MR4/DMR responses were achieved in 86.4%, 52.7%, 49.6%, and 23.5% patients respectively, which showed the lack of respective clinical responses at baseline. The patients without response at baseline, treated with flumatinib as 2L TKI, having no resistance to prior TKI or only resistance to imatinib, with response to last TKI, and with BCR::ABL ≤10% had higher CCyR/MR2, MMR, or MR4/DMR. The AEs observed during the later-line flumatinib treatment were tolerable and consistent with those reported with the first-line therapy. Flumatinib was effective and safe in patients who are resistant or intolerant to other TKIs. In particular, 2L flumatinib treatment induced high response rates and was more beneficial to patients without previous 2G TKI resistance, thus serving as a probable treatment option for these patients.

Assessment of prolonged proteasome inhibition through ixazomib-based oral regimen on newly diagnosed and first-relapsed multiple myeloma: A real-world Chinese cohort study.

OBJECTIVE: To evaluate the effectiveness, safety, and convenience of in-class transition (iCT) from intravenous bortezomib-based induction to ixazomib-based oral regimens. METHODS: This retrospective real-world study was conducted in 16 Chinese hospitals between October 2017 and April 2023 and analyzed newly diagnosed (NDMM) and first-line relapsed multiple myeloma (FRMM) patients who attained at least a partial response from bortezomib-based induction therapy, followed by an ixazomib-based oral regimen for 2 year or until disease progression or intolerable toxicity. RESULTS: The study enrolled 199 patients, median age: 63 years old, male 55.4%, 53% as high risk (HR), and 47% as standard risk. Cytogenetic risk stratification by metaphase fluorescence in situ hybridization (M-FISH), based on the Mayo Clinic risk stratification system. The median duration of total PI therapy was 11 months, with ixazomib-based treatment spanning 6 months. At the 20-month median follow-up, 53% of patients remained on therapy. The 24-month PFS rate was 84.3% from the initiation of bortezomib-based induction and 83.4% from the start of ixazomib-based treatment. Overall response rate (ORR) was 100% post-bortezomib induction and 90% following 6 cycles of the ixazomib-based regimen. Based on the Sankey diagrams, 89.51% of patients maintained or improved their disease response after 2 cycles of iCT, 6 cycles (90.14%), and 12 cycles (80%). The HR level of Mayo was found to be a significant independent factor in a worse remission (hazard ratio (HR) 2.55; p = 0.033). Ixazomib's safety profile aligned with previous clinical trial data, with 49% of patients experiencing at least one AE of any grade. The most common AEs included peripheral neuropathy, nausea and vomiting, diarrhea, thrombocytopenia, and granulocytopenia. CONCLUSION: In the real-world Chinese MM population, NDMM and FRMM patients responded favorably to PI-based continuous therapy, demonstrating substantial response rates. The ixazomib-based iCT allows for sustained PI-based treatment, offering promising efficacy and tolerable AEs.

Tumor-associated macrophages regulate the function of cytotoxic T lymphocyte through PD-1/PD-L1 pathway in multiple myeloma.

BACKGROUND: Tumor-associated macrophages (TAMs) are originated from circulating mononuclear cells in peripheral blood. They result from the recruitment of tumor cells and are a vital constituent of the tumor microenvironment. TAMs may be involved in the immunological escape of vicious clonal plasma cells (PC) in the bone marrow (BM) of sufferers with myeloma. METHODS: From March 2020 to January 2021, 28 healthy controls (HC) and 86 multiple myeloma (MM) (53 newly diagnosed MM [NDMM] and 33 remissions) patients were enrolled as objects of the study. The expression of TAMs in the BM, CSF1 on CD138 + cells, and CSF1R on macrophages were detected by the method of flow cytometry, and the expression of PD-1 on CD8 + T cells and PD-L1 on TAMs were also done. Bone marrow mononuclear cells (BMMNCs) were extracted and cultured into TAMs, CD8 + T cells were sorted by magnetic beads and cultured, a coculture system was established and different inhibitors were added. The expression of the perforin and granzyme B was detected by flow cytometry. RESULTS: The percentage of TAMs in NDMM group (61.49 ± 2.176%) increased when compared with remission (23.08 ± 1.699%, p < 0.001) and HC group (17.95 ± 1.865%, p < 0.001), and TAMs decreased after adding CSF1R inhibitor. Moreover, the expression of CSF1 on CD138 + cells increased significantly in NDMM group (17.090 ± 0.9156%) than remission (8.214 ± 0.5911% p < 0.001), and HC group (5.257 ± 0.6231%, p < 0.001), and CSF1R on macrophages increased significantly in NDMM group (58.78 ± 2.286%) than remission (20.74 ± 1.376%, p < 0.001) and HC group (17.42 ± 1.081%, p < 0.001). The expression of PD-1 on CD8 + T cells in NDMM group (32.64 ± 2.982%) increased than remission (20.35 ± 2.335% p < 0.01) and HC group (17.53 ± 1.349%, p < 0.001), and PD-L1 on TAMs also increased in NDMM group (50.92 ± 2.554%) than remission (20.02 ± 1.893%, p < 0.001) and HC group (13.08 ± 1.289%, p < 0.001). When CD8 + T cells were cocultured with TAMs, the perforin and granzyme B levels decreased significantly. However, the perforin and granzyme B levels were partly restored after adding CSF1R inhibitor and anti-PD-L1 antibody. CONCLUSION: Our study shows that TAMs were increased in MM patients which can inhibit the function of cytotoxic T lymphocyte (CTL) through the PD-1/ PD-L1 signaling pathway and participate in the occurrence of immune escape of myeloma cells.

Treatment and outcome patterns of patients with Waldenström's macroglobulinemia: a large, multicenter retrospective review in China.

In this study, we aimed to investigate treatment options and the prognosis of patients with WM in China. This retrospective study included 1141 patients diagnosed with symptomatic WM between January 2003 and December 2019 at 35 tertiary hospitals in 22 provinces of China. Fifty-four patients (7.3%) received monotherapy, 264 (36.0%) received chemoimmunotherapy, 395 (53.8%) received other combination regimens without rituximab, and 21 (2.9%) received ibrutinib. Using a multivariable Cox regression model, age > 65 years old, platelets <100 × 109/L, serum albumin <3.5 g/dl, ß2 microglobulin concentration ≥4 mg/L and LDH ≥250 IU/L predicted poor OS. In summary, our study showed that frontline treatment choices for WM are widely heterogeneous. We validated most of the established prognostic factors in the rIPSS (age >65 years, LDH ≥250 IU/L, ALB <3.5 g/dl and ß2 microglobulin ≥4 mg/L) together with PLT ≤ 100 × 109/L indicate a poor prognosis for patients with WM.

Stanozolol improves the progression-free survival of patients with high-risk myelodysplastic syndrome after decitabine treatment.

It is unknown whether adding stanozolol to decitabine for maintenance can further improve progression-free survival (PFS) and overall survival (OS) after effective decitabine treatment in patients with high-risk myelodysplastic syndrome (MDS). Patients newly diagnosed with high-risk MDS who achieved at least partial remission after 4 cycles of decitabine (20 mg/m2 days 1-5) were selected. In total, 62 patients (median age 66 years) were enrolled, of whom 21 were treated with stanozolol and decitabine for maintenance, and 41 were treated with decitabine alone. The median number of cycles for maintenance treatment was 6 (2-11) and 5 (2-12) for the stanozolol and control groups, respectively (p > 0.05). PFS in the stanozolol group was significantly longer than in the control group (15.0 vs 9.0 months, hazard ratio [HR] = 0.35, 95%CI: 0.19-0.63, p = 0.0005), whereas OS was not significantly prolonged in the stanozolol group (21.0 vs 15.0 months, HR = 0.73, 95%CI: 0.39-1.37, p = 0.33). The proportion of patients with severe neutropenia during maintenance treatment in the stanozolol group was lower than in the control group (76.2% vs 95.1%, p = 0.039). In conclusion, adding stanozolol to decitabine after effective decitabine treatment can prolong PFS and reduce the severity of neutropenia for patients with high-risk MDS.

Ixazomib-based frontline therapy in patients with newly diagnosed multiple myeloma in real-life practice showed comparable efficacy and safety profile with those reported in clinical trial: a multi-center study.

The induction therapy containing ixazomib, an oral proteasome inhibitor, has shown favorable efficacy and safety in clinical trials, but its experience in real-life remains limited. In routine practice, few patients received ixazomib-based induction therapy due to reasons including (1) patients' preference on oral regimens, (2) concerns on adverse events (AEs) of other intravenous/subcutaneous regimens, (3) requirements for less center visits, and (4) fears of COVID-19 and other infectious disease exposures. With the aim of assessing the real-life effectiveness and safety of ixazomib-based induction therapy, we performed this multi-center, observational study on 85 newly diagnosed multiple myeloma (NDMM) patients from 14 medical centers. Ixazomib-based regimens included ixazomib-lenalidomide-dexamethasone (IRd) in 44.7% of patients, ixazomib-dexamethasone (Id) in 29.4%, and Id plus another agent (doxorubicin, cyclophosphamide, thalidomide, or daratumumab) in 25.9%. Different ixazomib-based therapies were applied due to (1) financial burdens or limitations on local health insurance coverage, (2) concerns on treatment tolerance, and (3) drug accessibility issue. Ten patients received ixazomib maintenance. The median age was 67 years; 43.5% had ISS stage III disease; 48.2% had an Eastern Cooperative Oncology Group performance score ≥ 2; and 17.6% with high-risk cytogenetic abnormalities. Overall response rate for all 85 patients was 95.3%, including 65.9% very good partial response or better and 29.5% complete responses. The median time to response was 30 days. The response rate was similar across different ixazomib-based regimens. Median progression-free survival was not reached. Severe AEs (≥ grade 3) were reported in 29.4% of patients. No grade 3/4 peripheral neuropathy (PN) occurred. Patients received a median of 6 (range 1-20) cycles of ixazomib treatment; 56.6% remained on treatment at data cutoff; 15.3% discontinued treatment due to intolerable AEs. These results support that the ixazomib-based frontline therapy was highly effective with acceptable toxicity in routine practice and the ixazomib oral regimens could be good alternative options for NDMM patients.

[Inhibitory Effect of Decitabine-inhibeting Methylation of SHP-1 Gene on Proliferation and Apoptosis of MDS Cell Line Skm-1].

OBJECTIVE: To investigate the phenotype and molecular mechanism of DCA on MDS cell model, and to study the response of chemotherapeutic medicines to MDS cells through multiple dimensions, such as cell proliferation, invasion, migration and apoptosis, thus revealing the molecular mechanism of DCA treatment of MDS and its relationship with SHP-1 gene methylation. METHODS: MTT assay was used to determine the survival rate of MDS cells after treated by different concentrations of DCA. The effect of DCA on the invasion and migration of MDS cells was detected by Transwell assay method. Apoplexin V-FITCPI was used to detect apoptosis, the MDS treatment on the mechanism of DCA was investigated by Western blot and Real-time PCR experiment. RESULTS: According to the experiment, it was found that tumor proliferation could be inhibited when MDS skm-1 cells was treated by DCA, and the absorbance was lower and the inhibitory effect was more obvious in the 2.0, 5.0 µmol/L DCA group than in the 0.5 µmol/L DCA group and the negative control group. Compared with the control group, the number of MDS skm-1 cells crossing through the transwell upper chamber was significantly decreased after DCA application. After treated with 0.5, 2.0 and 5.0 µmol/L DCA, the apoptosis rate of MDS cells was 4.54%, 9.31% and 16.58% respectively, while the apoptosis rate of the control group was 3.20%, which shows the apoptosis rate increased significantly with the concentration of DCA. After treatment of MDS cell lines with different concentration of DCA, the methylation status of SHP-1 gene was decreased with the increase of drug concentration, the expression of SHP-1 was increased, the expression of STAT3 was decreased and the level of phosphorylation was decreased. CONCLUSION: By analyzing the phenotypic response of DCA treatment on MDS cells, it was found that interfere with MDS can be performed by inhibiting proliferation, metastasis, and inducing apoptosis in a dose-dependent way. It revealed that the molecular mechanism by DCA treatment can improve the methylation of SHP-1 gene and inhibit the expression of p-STAT3.

[Predicting Therapeutic Response by Lymphocyte Level at 28th Day after DAC Treatment in Patients with MDS].

OBJECTIVE: To investigate a reliable clinical indication for predicting the therapeutic response of decitabine therapy in the patients with myelodysplastic syndromes (MDS). METHODS: The clinical efficacy of decitabine for 55 cases of MDS was analyzed retrospectively. According to the lymphocyte level at d28 after the first time treatment with decitabine, the patients were divided into high lymphocyte level group (H-Lym≥1.2×109/L) and low lymphocyte level group (L-Lym<1.2×109/L), and the overall response rate (ORR) and the progression-free survival (PFS) time in 2 groups were compared. RESULTS: As compared with L-Lym group, the ORR and PFS time in H-Lym group were significantly enhanced ï¼»(76.0% vs 50.0%) (P<0.05) and median time (15.7 months vs 8.5 months)(P<0.05), respectivelyï¼½;the ratio of platelet level ≥100×109/L in H-Lym group was very significantly higher than that in L-Lym group (72.0% vs 20.0%)(P<0.01). Multivariat analysis showed that the risk of disease progression in L-Lym group was 4.45-fold of H-Lym group (95% CI:1.58-12.59)(P<0.05). CONCLUSION: The patients with lymphocyte level ≥1.2×109/L at day 28 after the first time treatment with decitabine show the higher ORR and longer PFS time, therefore. the lymphocyte level at day 28 after first time treatment with decitabine can be used as an early clinical indicator for predecting the response to decitabine treatment.

[Mechanism and Its Countermeasure of Hypomethylating Agent Resistance in Patients with Myelodysplastic Syndrome--Review].

Hypomethylating agents(HMA) currently are widely used in the treatment of myelodysplastic syndromes (MDS), provide a significant improvement in the treatment of MDS. However, resistance to HMA is an almost universal phenomenon. This review was focused on immune effects related to DNA methylation, and to explore the mechanism underlying HMA resistance involved in immune checkpoint pathways. However, the optimal role of checkpoint blockade therapy (CBT) and immune checkpoint pathways remain in HMA failure questionable. The better understanding of immune checkpoint pathways in resistance of HMA offers a compelling rationale to introduce CBT in patients as a novel treatment option. CBT is an established strategy in solid tumors with potential as an adjunctive therapy in hematologic malignancies, therefore, may alter the treatment landscape in MDS. The suitability and effectiveness of combining HMA with CBT need to be confirmed by the results of ongoing clinical trials, so as to find novel strategies to improve outcome after failure of HMA.

[Lymphocyte Count before First Consolidation Therapy Is A Predictor of Relapse free Survival in Acute Myeloid Leukemia].

OBJECTIVE: To investigate the effects of absolute lymphocyte count(ALC) before start of the first cycle of consolidation chemotherapy(CC) on the relapse free survival in the patients with acute myeloid leukemia(AML), so as to explore a simple and easy method for predicting AML relapse. METHODS: The clinical data of 132 patients with newly diagnosed AML (all non-acute promyelotic leukemia) from 2011 to 2017 were analyzed retrospectively. The 132 AML patients were treated with standard induction chemotherapy (IC) and consolidation chemotherapy (CC). According to lymphocyte count of patients before start of the first cycle of CC, the AML patients were divided into 2 group: high lymphocyte count group (H-Lym≥1.2×109/L) and low lymphocyte count group (L-Lym<1.2×109/L). The differences in ralapse rate and relapse-free survival between 2 groups were analyzed. RESULTS: Among 132 patients with AML, patients who could be valuated and were elicible for the study accounted for 65 (49.24%). The absolute leukocyte count, age, chromosome karyotypes before IC of patients did not show statistical difference between H-Lym group (40 cases) and L-Lym group (25 cases). Unvarvate analysis showed that the Low lymphocyte count and unfavorable chromosome karyotypes were poor prognostic factors for the relapse-free survival time, and there was significant difference between 2 groups (P<0.01). The relapse risk in patients of L-Lym group increased, the hazard ratio (HR)=3.01 (95% CI=1.55-4.98) (P<0.01). In multivariate analysis containing unfavorable prognostic karyotypes, this trend still existed (HR=2.52, 95% CI 1.28-9.98)(P<0.01). CONCLUSION: The AML patients with high lymphocyte count before the first CC have more long relapse free survival time suggesting that the lymphocyte count before the first CC may be prognostic factor for relapse free survival of AML patients.

[Research Advances of Molecular Genetic Abnormality in Myelodysplastic Syndrome--Review].

The myelodysplastic syndromes (MDS) are a heterogeneous group of clonal myeloid disorders characterized by ineffective hematopoiesis and increased risk of transformation to acute myelogenous leukemia (AML). The treatment of MDS is highly dependent on the reliability of the prognostic evaluation model. Current clinical prognostic scoring systems are comprised of morphology, pivotal clinical trials and cytogenetic findings. However, none of the available prognostic systems incorporates disease-related molecular abnormalities, such as somatic mutations. Cumulative evidence suggests that genomic data can also be used clinically to assist the diagnosis, prognosis, prediction of response to specific therapies, and the development of novel and accurate targeted therapies. Therefore, it is not possible to predict the response of patients to molecular targeted drugs, such as demethylation drugs. With the recent advance in whole- genome sequencing technologies, cumulative evidence suggests that genomic data can also be associated with the genesis, prognosis, prediction of response to specific therapies, and the development of novel accuvate targeted therapies, the issue of having some mechanism to dissect this heterogeneity and precision treatment is coming to the fore. However, there are still several hindrances to its clinical application. If these problems can be solved, molecular genetics will further provide a theoretical basis for the application of precision medicine in MDS.

Characteristics and clinical significance of osteogenic differentiation of mesenchymal stem cells derived from bone marrow in patients with myelodysplastic syndromes / 中国肿瘤生物治疗杂志

@#[Abstract] Objective: To investigate the osteogenic differentiation characteristics of mesenchymal stem cell (MSC) derived from bone marrow in patients with myelodysplastic syndromes (MDS) and its clinical significance. Methods: Bone marrow samples from 30 cases of newly diagnosed untreated MDS patient atAffiliated Hospital of Heibei University were collected for this study. MSCs from MDS patients and normal subjects were isolated and cultured, and morphological characteristics of MSCs were observed in vitro; under proper conditions, MSCs were induced to differentiate into osteoblasts and adipocytes; The formation of calcium nodules at 14th day after osteogenic differentiation was observed by alizarin red staining; mRNA expressions of osteogenic differentiation transcription factors Ostefix and RUNX2 in undifferentiated MSCs, as well as the mRNAexpression of Jagged-1, which involved in the transformation from hematopoietic cells into leukemic cells, were detected by quantitative PCR. Results: The MSCs derived from patients with MDS were characterized with increased cell volume and decreased differentiation potential. Compared with the control group, the expression levels of osteogenic differentiation transcription factors Osterix and RUNX2 were significantly decreased (P < 0.05). Alizarin red staining showed that the content of calcium nodules in MDS group was significantly less than that in the normal control group, while the expression level of Jagged-1 was significantly higher (P < 0.05). Conclusion: MSCs derived from bone marrow of MDS patients showed significant increased cell volume, decreased differentiation potential and elevated Jagged-1 expression; all of these might play important roles in the .hematopoietic failure and progression to acute myeloid leukemia in MDS patients.

Notable roles of EZH2 and DNMT1 in epigenetic dormancy of the SHP1 gene during the progression of chronic myeloid leukaemia.

Tumor development is associated with the methylation of cytosine-guanine (CpG) islands. The occurrence of methylation requires several factors, such as DNA methylation systems and polycomb group (PcG) proteins. At present, novel drugs are needed for the treatment of chronic myeloid leukaemia (CML), particularly considering the current prognosis of CML. The methylation status of the Src homology 2 domain-containing tyrosine phosphatase 1 (SHP1) gene, a negative regulator of signal transduction, has been identified as being altered in numerous haematological malignancies. DNA methyltransferase 1 (DNMT1) and the PcG protein complex member enhancer of zeste homolog 2 (EZH2) participate in a number of gene methylation processes. The present study investigated the methylation status of the SHP1 gene in CML, and examined the association between DNMT1 and EZH2 activity and the SHP1 gene methylation status to develop novel strategies for the treatment of CML. The results revealed that SHP1 gene methylation status was altered during the progression of CML. These data indicated that SHP1 gene methylation is associated with the progression of this disease. The associations of DNMT1 and EZH2 activities with the methylation status of the SHP1 gene were additionally investigated via chromatin immunoprecipitation. DNMT1 and EZH2 were revealed to be bound to the promoter region of the SHP1 gene, and were involved in the process of SHP1 methylation. Furthermore, DNMT1 and EZH2 were associated with disease progression. Thus, the findings of the present study suggest a new target for the treatment of CML, particularly for future drug development.

[Efects of Inhibiting miR-155 Expression on the Proliferation and Apoptosis of Leukemia THP-1 Cells].

The aim of this study was to investigate the effects of miR-155 inhibitor transfection on the proliferation and apoptosis of THP-1 cells. The miR-155 inhibitor was transfected into THP-1 cells (THP-1I) by using X-treme GENE siRNA transfection reagent. Cells without transfection (THP-1C) and cells with negative transfection (THP-1IC) were used as controls. Quantitative real-time polymerase chain reaction (RT-PCR) was performed to detect the expression of miR-155 and relative expression of SHIP1 mRNA in the cells. Cell proliferation was assayed using CCK-8 method. Cell apoptosis were detected by flow cytometry. The expression of SHIP1, TAKT and pAKT in THP-1 cells were detected by Western blot. The results indicated that compared with THP-1C and THP-1IC, the expression of miR-155 in THP-1I cells was significantly reduced; miR-155 inhibition significantly increased apoptosis rate in THP-1 cells (P < 0.05) ; miR-155 inhibition in THP-1 cells caused no significant alteration in SHIP1 mRNA level but significantly increased its protein content, indicating some post-transcriptional modulations might exist underlying the modulation of miR-155 to SHIP1, the miR-155 caused significantly reduced protein level of pAKT (P < 0.05) without interfering TAKT protein content. It is concluded that the miR-155 inhibition may promote THP-1 cell apoptosis through increasing SHIP1 protein content and impairing its downstream PI3K/AKT signaling pathway. This study suggests that miR-155 inhibition may be a promising therapy strategy for treating acute myeloid leukemia (AML).

SHIP1 is targeted by miR-155 in acute myeloid leukemia.

The SH2 domain-containing inositol 5'-phosphatase 1 (SHIP1) has been implicated as a suppressor of hematopoietic transformation as its activity can inhibit the PI3K/Akt signaling pathway. Reduced activity of SHIP1 has been observed in acute myeloid leukemia (AML). SHIP1 is a target of microRNA-155 (miR-155). Therefore, the aim of the present study was to investigate the role of miR-155/SHIP1 in the pathogenesis of AML. We examined the levels of SHIP1 protein and miR-155 in tissue samples of patients with AML and in AML cell lines. In addition, we investigated cell proliferation, apoptosis and expression of SHIP1/PI3K/AKT pathway molecules in the THP-1 and U937 cell lines after miR-155 inhibitor or mimics were transfected. We showed that the levels of SHIP1 protein were significantly decreased in tissue samples of patients with some subtypes of AML (M4 or M5) and in AML cell lines with concomitant overexpression of miR-155. In addition, we demonstrated that decreased expression of SHIP1 in the AML cell lines was a consequence of increased levels of miR-155 and can therefore be reversed in vitro through inhibition of miR-155, with subsequent inhibition of cell proliferation and promotion of cell apoptosis. In conclusion, expression of the SHIP1 protein is targeted by miR-155 in AML. miR-155 acts as an onco-miR, and the miR-155/SHIP1/PI3K/AKT signaling pathway could play an important role in the pathogenesis of AML.

[Relationship between microRNA-155 and hematological malignancies].

MicroRNA (miRNA) are small non-coding RNA that act at the post-transcriptional level, regulating protein expression by repressing translation mRNA target. They can be detected in plants, animal species and viruses, and are involved in numerous cellular processes. MicroRNA-155 (miR-155) which is a kind of microRNAs expressed in hematopoietic cells. Recent data indicate that MiR-155 plays a key role in the pathogenesis of hematological malignancies through regulating cell signal transduction pathways of cell proliferation, differentiation and apoptosis, acting predominantly as an oncomir. MiR-155 may be an important indicator to assess the diagnosis, treatment and prognosis of patients with hematological malignancies, including malignant lymphoma, acute myeloid leukemia, and myelodysplastic syndrome. It could be suggested that drugs such as antisense oligonucleotides able to down-regulate miR-155 expression would provide a novel, and possibly specific way to control the growth of a range of haematopoietic malignancies in conjunction with classical cytotoxic therapy. The purpose of this review is to summarize current findings on the role of miR-155 in hematopoietic malignancies and, moreover, to highlight their role as potential therapeutic tools.