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1.
Adv Hematol ; 2019: 1486476, 2019.
Article in English | MEDLINE | ID: mdl-31781224

ABSTRACT

The coexistence of a myeloid and a lymphoid neoplasm in the same patient is a rare finding. We retrospectively searched the records of the Hematology Division of the Second Department of Internal Medicine and Research Institute at Attikon University General Hospital of Athens from 2003 to 2018. Nine cases have been identified in a total of 244 BCR-/ABL1- negative MPN and 25 MDS/MPN patients and 1062 LPD patients referred to our institution between 2003 and 2018. Each case is distinct in the diversity of myeloid and lymphoid entities, the chronological occurrence of the two neoplasms, and the patient clinical course. All of them exhibit myeloproliferative (6 JAK2 V617F-positive cases) and lymphoproliferative features, with 1 monoclonal B-cell lymphocytosis (MBL), 3 B-chronic lymphocytic leukemias (B-CLL), 3 B-non-Hodgkin lymphomas (B-NHL), 1 multiple myeloma (MM), and 1 light and heavy deposition disease (LHCDD), while in three cases myelodysplasia is also present. The challenges in identifying and dealing with these rare situations in everyday clinical practice are depicted in this article.

2.
Leuk Lymphoma ; 60(3): 658-667, 2019 03.
Article in English | MEDLINE | ID: mdl-29911923

ABSTRACT

MicroRNA-92a-3p (miR-92a-3p) derives from the oncogenic miR-17/92 cluster and its highly homologous miR-106a/363 cluster. miR-92a-3p regulates the expression of key transcription factors such as HIF1 and inhibits SOCS1 to enhance the anti-apoptotic STAT3/IL6 signaling pathway. In this study, we assessed the putative usefulness of miR-92a-3p as a prognostic and/or diagnostic biomarker in chronic lymphocytic leukemia (CLL). For this purpose, total RNA was extracted from mononuclear cells isolated from the peripheral blood of 88 CLL patients and 36 non-leukemic blood donors, was polyadenylated and reversely transcribed. miR-92a-3p expression was quantified using an accurate qPCR method. miR-92a-3p levels were significantly lower in peripheral blood mononuclear cells of CLL patients. Overall survival (OS) analysis revealed that high miR-92a-3p expression predicts significantly prolonged OS of CLL patients. Interestingly, miR-92a-3p overexpression remains a significant prognosticator in subgroups of CLL patients with distinct prognosis. In conclusion, miR-92a-3p overexpression is a potential surrogate biomarker of favorable outcome of CLL patients.


Subject(s)
Biomarkers, Tumor , Gene Expression Regulation, Neoplastic , Leukemia, Lymphocytic, Chronic, B-Cell/genetics , Leukemia, Lymphocytic, Chronic, B-Cell/mortality , Leukocytes, Mononuclear/metabolism , MicroRNAs/genetics , Aged , Aged, 80 and over , Case-Control Studies , Cell Line, Tumor , Female , Humans , Immunoglobulin Heavy Chains/genetics , Kaplan-Meier Estimate , Leukemia, Lymphocytic, Chronic, B-Cell/diagnosis , Male , Middle Aged , Mutation , Prognosis , Proportional Hazards Models
3.
Hematol Oncol ; 36(4): 693-700, 2018 Oct.
Article in English | MEDLINE | ID: mdl-30129144

ABSTRACT

The demethylating factor 5-azacytidine (5-AZA) improves survival in intermediate-2 and high-risk myelodysplastic syndrome (MDS) patients [according to the International Prognostic Score System (IPSS)] responding to treatment. However, the outcome of patients achieving stable disease (SD) is unclear. This retrospective study of the Hellenic MDS Study Group included 353 intermediate-2 or high IPSS risk patients treated with 5-AZA. Forty-four out of 86 (51.6%) patients achieving SD and continuing treatment with 5-AZA showed a lower risk of transformation of MDS to acute myeloid leukemia (AML) and increased overall survival (OS), compared to SD patients who discontinued the treatment (estimated median AML-free survival = 38 months, 95% CI = 10.7-65.3 vs 15 months, 95% CI = 10.4-19.6, P < .001; estimated median OS = 20 months, 95% CI = 5.5-34.5 vs 11 months, 95% CI = 5.8-16.2, P < .001). Moreover, SD patients continuing treatment with 5-AZA had no differences in AML-free survival compared to patients showing response to 5-AZA (estimated median AML-free survival = 38 months, 95% CI = 10.7-65.3 vs 31 months, 95% CI = 23.6-38.4, P = .45; estimated median OS 20 months, 95% CI = 5.5-34.5 vs 25 months, 95% CI = 21.3-28.7, P = .50). In conclusion, MDS patients achieving SD in the first 6 months of treatment with 5-AZA as best response should continue receiving 5-AZA as they may benefit from prolonged treatment.


Subject(s)
Antimetabolites, Antineoplastic/therapeutic use , Azacitidine/therapeutic use , Myelodysplastic Syndromes/drug therapy , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Prognosis , Retrospective Studies , Risk Factors , Survival Rate , Treatment Outcome
4.
Leuk Res ; 70: 1-7, 2018 07.
Article in English | MEDLINE | ID: mdl-29715621

ABSTRACT

MicroRNA-20b-5p (miR-20b-5p) is part of the miR-106a/363 cluster and a member of the cancer-related miR-17 family. miR-20b-5p regulates important transcription factors, including hypoxia-inducible factor 1 (HIF1) and signal transducer and activator of transcription 3 (STAT3). Recently, the dysregulation of miR-20b-5p expression has been observed in many B-cell lymphomas and T-cell leukemias. In this research study, we examined the putative prognostic value of miR-20b-5p in CLL. Therefore, total RNA was isolated from peripheral blood mononuclear cells (PBMCs) collected from 88 CLL patients; next, total RNA was polyadenylated and first-strand cDNA was synthesized, using an oligo-dT-adapter primer. miR-20b-5p expression was quantified using an in-house-developed real-time quantitative PCR assay. Kaplan-Meier OS analysis and bootstrap univariate Cox regression showed that high miR-20b-5p expression predicts better OS for CLL patients (p < 0.001). Interestingly, miR-20b-5p overexpression retains its favorable prognostic role in CLL patients of intermediate risk or stratified according to established prognostic factors [CD38 expression and mutational status of the immunoglobulin heavy chain variable (IGHV) region]. In conclusion, miR-20b-5p is a potential independent molecular biomarker of favorable prognosis in CLL.


Subject(s)
Biomarkers, Tumor , Gene Expression Regulation, Leukemic , Leukemia, Lymphocytic, Chronic, B-Cell/genetics , Leukemia, Lymphocytic, Chronic, B-Cell/mortality , Leukocytes, Mononuclear/metabolism , MicroRNAs/genetics , Aged , Cell Line, Tumor , Female , Humans , Immunoglobulin Heavy Chains/genetics , Kaplan-Meier Estimate , Leukemia, Lymphocytic, Chronic, B-Cell/diagnosis , Male , Middle Aged , Mutation , Neoplasm Staging , Prognosis , Proportional Hazards Models
5.
Am J Hematol ; 93(7): 895-901, 2018 07.
Article in English | MEDLINE | ID: mdl-29659040

ABSTRACT

In this study, we investigated the incidence and prognostic impact of monosomal karyotype (MK) in 405 higher-risk Myelodysplastic Syndromes (MDS) patients treated with 5-AZA. The MK was present in 66 out of 405 (16.3%) patients, most of whom had complex karyotype (CK). MK was strongly associated with CK and the cytogenetic risk defined according to IPSS-R, as well as with high-risk disease, according to IPSS (P = .029), IPSS-R (P < .001), and WPSS (P < .001) classification systems. The overall response rate (ORR) was not different between MK+ and MK- patients (46.6% vs. 46.2%). At 28 months median follow-up, the median duration of response was 11 months in the entire cohort, 9.5 months in MK+ patients and 11 months in MK-patients (P = .024). The estimated median time to transformation to acute myeloid leukemia for MK+ patients was 17 months vs. 23 months for MK- patients (P = .025). The estimated median OS for MK+ patients was 12 months vs. 18 months for MK- patients (P < .001). Multivariate Cox regression analysis revealed that performance status (P < .001), IPSS-R (P < .001), and MK (P = .002) were independently associated with overall survival (OS). In a subgroup consisting of high and very-high risk patients according to IPSS-R, MK- patients showed better OS rates compared to MK+ patients (estimated median OS: 17 months vs. 12 months, P = .002). In conclusion, we found that MK is associated with reduced OS in patients with higher-risk MDS treated with 5-AZA. Furthermore, we showed that in MDS with high or very-high IPSS-R risk score, MK can further distinguish patients with worse outcome.


Subject(s)
Azacitidine/therapeutic use , Karyotype , Monosomy , Myelodysplastic Syndromes/diagnosis , Adult , Aged , Aged, 80 and over , Cell Transformation, Neoplastic , Female , Greece , Humans , Leukemia, Myeloid, Acute , Male , Middle Aged , Myelodysplastic Syndromes/drug therapy , Myelodysplastic Syndromes/genetics , Myelodysplastic Syndromes/mortality , Prognosis , Retrospective Studies , Survival Analysis , Treatment Outcome
6.
Leuk Lymphoma ; 59(10): 2439-2446, 2018 10.
Article in English | MEDLINE | ID: mdl-29411666

ABSTRACT

Mutations of ASXL1 are early events in acute myeloid leukemia (AML) leukemogenesis and have been associated with unfavorable prognosis. In this study, we investigated the type and frequency of ASXL1 mutations in a large cohort of patients with de novo or secondary AML (s-AML) and looked for correlations with cytogenetic findings and disease features. ASXL1 mutations were associated with older age, s-AML and higher peripheral leukocytosis. We observed more frequent co-occurrence of ASXL1 mutations with trisomy 8 and chromosome 11 aberrations but a negative correlation with myelodysplastic syndromes (MDS)-related cytogenetic abnormalities, especially -5/del(5q) and -7/del(7q). ASXL1 mutations were also found in other genetically defined AML subgroups such as those with t(9;22), inv(3)/t(3;3), t(8;21) or t(15;17); however, none of our inv(16) cases carried ASXL1 mutations. We detected two previously unreported ASXL1 mutations, p.IIe593Val and p.Cys688Tyr. Our findings suggest that ASXL1 mutations tend to cluster with specific clinical and cytogenetic profiles of AML patients.


Subject(s)
Chromosome Aberrations , Leukemia, Myeloid, Acute/genetics , Myelodysplastic Syndromes/genetics , Neoplasms, Second Primary/genetics , Repressor Proteins/genetics , Adolescent , Adult , Age Factors , Aged , Carcinogenesis/genetics , Case-Control Studies , Cohort Studies , Female , Humans , Leukemia, Myeloid, Acute/blood , Leukocytosis/blood , Leukocytosis/genetics , Male , Middle Aged , Mutation
7.
Leuk Res ; 60: 74-81, 2017 09.
Article in English | MEDLINE | ID: mdl-28759799

ABSTRACT

Accumulated data indicate a significant role of T cell dysfunction in the pathogenesis of chronic lymphocytic leukemia. In CLL, regulatory T cells are significantly higher and show lower apoptotic levels compared to healthy donors. We demonstrate that CLL derived CD4+CD25-CD127- and CD4+CD25lowCD127- subpopulations share a common immunophenotypic profile with conventional Tregs and are associated with advanced stage disease. We further provide evidence that the increased number of Tregs contributes indirectly to the proliferation of the CLL clone, by suppressing the proliferation of Teffs which in turn suppress CLL cells. These data are further supported by our observations that CLL derived Tregs appear rather incapable of inducing apoptosis of both normal B cells and CLL cells, in contrast to normal Tregs, suggesting an immunoediting effect of CLL cells on Tregs which negatively affects the functionality of the latter and contributes to the failure of Tregs in CLL to efficiently eliminate the abnormal clone.


Subject(s)
Leukemia, Lymphocytic, Chronic, B-Cell/pathology , T-Lymphocytes, Regulatory , Adult , Aged , Aged, 80 and over , Apoptosis , CD4 Lymphocyte Count , Cell Proliferation , Female , Humans , Immunophenotyping , Leukemia, Lymphocytic, Chronic, B-Cell/immunology , Male , Middle Aged
8.
PLoS One ; 12(1): e0170186, 2017.
Article in English | MEDLINE | ID: mdl-28107479

ABSTRACT

Mycosis fungoides (MF) and its leukemic variant Sézary syndrome (SS) comprise the majority of CTCL, a heterogenous group of non-Hodgkins lymphomas involving the skin. The CTCL's resistance to chemotherapy and the lack of full understanding of their pathogenesis request further investigation. With the view of a more targeted therapy, we evaluated in vitro the effectiveness of bortezomib and methotrexate, as well as their combination in CTCL cell lines, regarding apoptosis induction. Our data are of clinical value and indicate that the bortezomib/methotrexate combinational therapy has an inferior impact on the apoptosis of CTCL compared to monotherapy, with bortezomib presenting as the most efficient treatment option for SS and methotrexate for MF. Using PCR arrays technology, we also investigated the alterations in the expression profile of genes related to DNA repair pathways in CTCL cell lines after treatment with bortezomib or methotrexate. We found that both agents, but mostly bortezomib, significantly deregulate a large number of genes in SS and MF cell lines, suggesting another pathway through which these agents could induce apoptosis in CTCL. Finally, we show that SS and MF respond differently to treatment, verifying their distinct nature and further emphasizing the need for discrete treatment approaches.


Subject(s)
Antineoplastic Agents/pharmacology , Apoptosis/drug effects , Bortezomib/pharmacology , Gene Expression Profiling , Lymphoma, T-Cell, Cutaneous/pathology , Methotrexate/pharmacology , Cell Line, Tumor , DNA Repair , Flow Cytometry , Humans , Lymphoma, T-Cell, Cutaneous/genetics , Polymerase Chain Reaction , Signal Transduction
9.
Leuk Res ; 53: 65-73, 2017 02.
Article in English | MEDLINE | ID: mdl-28038356

ABSTRACT

The hypoxia inducible factor 1 (HIF1) is a heterodimeric transcription factor that ultimately regulates cellular responses to changes in oxygen tension. In this study, we examined the potential diagnostic and prognostic potential of the mRNA expression of HIF1 regulatory α-subunit (HIF1A) in chronic lymphocytic leukemia (CLL). For this purpose, total RNA was isolated from peripheral blood mononuclear cells collected from 88 CLL patients and 33 non-leukemic blood donors, and poly(A)-RNA was reversely transcribed. HIF1A mRNA levels were quantified using real-time PCR. Kaplan-Meier survival analysis showed that high HIF1A mRNA expression predicts inferior overall survival for CLL patients (p=0.001). Bootstrap univariate Cox regression analysis confirmed that HIF1A mRNA overexpression is a significant unfavorable prognosticator in CLL (hazard ratio=3.75, bias-corrected and accelerated 95% confidence interval=1.43-24.36, bootstrap p<0.001), independent of other established prognostic factors, including CD38 expression, the mutational status of the immunoglobulin heavy chain variable region (IGHV), and the clinical stage (Binet or Rai stage) or risk group (p<0.001 in all cases). Interestingly, HIF1A mRNA positivity retains its unfavorable prognostic value in distinct subgroups of patients, stratified according to established prognostic factors. Thus, HIF1A mRNA overexpression can be regarded as a promising, independent molecular biomarker of unfavorable prognosis in CLL.


Subject(s)
Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Leukemia, Lymphocytic, Chronic, B-Cell/diagnosis , Biomarkers, Tumor/blood , Case-Control Studies , Humans , Leukemia, Lymphocytic, Chronic, B-Cell/mortality , Prognosis , RNA, Messenger/analysis , Survival Rate
11.
Future Oncol ; 12(13): 1587-93, 2016 Jul.
Article in English | MEDLINE | ID: mdl-27079806

ABSTRACT

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is a rare low-grade B-cell non-Hodgkin lymphoma associated with Helicobacter pylori infection and the subsequent chronic inflammation. Significant progress in understanding the pathogenesis of the disease has already been made. However, the exact molecular pathways of lymphomagenesis remain unclear. Furthermore, difficulties regarding accurate diagnosis of gastric MALT lymphoma and its discrimination from gastritis or other lymphoma subtypes arise. Recent studies evaluate the role of miRNAs and epigenetic alterations on MALT lymphoma pathogenesis and prognosis. This review critically summarizes the most important data on the role of miRNAs and epigenetics in MALT lymphomas pathogenesis, prognosis and treatment.


Subject(s)
Epigenesis, Genetic/genetics , Lymphoma, B-Cell, Marginal Zone/genetics , MicroRNAs/genetics , Stomach Neoplasms/genetics , Humans
12.
Hematology ; 21(1): 34-41, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26218077

ABSTRACT

OBJECTIVES: The demethylating factor 5-Azacytidine (5-AZA) improves survival of patients with myelodysplastic syndromes (MDS) in randomized control trials but the results in 'real life' are controversial. METHODS: In this retrospective study, we evaluated the outcome of 56 high-risk MDS patients who were treated with 5-AZA between 2005 and 2013. 5-AZA was administered in an outpatient basis at a dose 75 mg/m(2) s.c. with the following schedule: 5 days on/weekend off/2 days on (5/2/2). RESULTS: The overall response rate (ORR) was 50%; 21.2% patients achieved complete response (CR), 3.8% partial response (PR), and 25% hematologic improvement (HI); 34.6% had stable disease (SD) and 15.4% showed progressive disease (PD). The estimated median event free survival (EFS) and overall survival (OS) were 11 and 17 months, respectively. Interestingly, the estimated time to acute myeloid leukemia transformation was 30 months, which refers to patients who responded to AZA treatment or remained stable. Patients who responded to the 5-AZA achieving CR, PR, and HI had better EFS and OS compared to the patients who had SD or PD. In addition, Δ WHO Classification-based Prognostic Score System (ΔWPSS), which represents the improvement of WPSS risk group before and after treatment, was associated with significantly improved OS and better EFS. Finally, the response to treatment was not associated with the expression of p53. CONCLUSIONS: In conclusion, 5-AZA is an effective treatment for high-risk MDS. Improved OS and EFS were found mainly in patients who responded to the treatment while ΔWPSS seems to represent a promising future prognostic tool.


Subject(s)
Antimetabolites, Antineoplastic/therapeutic use , Azacitidine/therapeutic use , Leukemia, Myeloid, Acute/drug therapy , Myelodysplastic Syndromes/drug therapy , Tumor Suppressor Protein p53/genetics , Aged , Aged, 80 and over , Drug Administration Schedule , Female , Gene Expression , Humans , Leukemia, Myeloid, Acute/diagnosis , Leukemia, Myeloid, Acute/etiology , Leukemia, Myeloid, Acute/mortality , Male , Middle Aged , Myelodysplastic Syndromes/complications , Myelodysplastic Syndromes/diagnosis , Myelodysplastic Syndromes/mortality , Prognosis , Remission Induction , Retrospective Studies , Risk Assessment , Survival Analysis , Treatment Outcome
13.
Epigenomics ; 7(6): 951-9, 2015.
Article in English | MEDLINE | ID: mdl-26443384

ABSTRACT

miRNAs are small noncoding RNAs that regulate gene expression at the post-transcriptional level. Since their discovery, miRNAs have been associated with every cell function including malignant transformation and metastasis. Endometrial cancer is the most common gynecologic malignancy. However, improvement should be made in interobserver agreement on histological typing and individualized therapeutic approaches. This article summarizes the role of miRNAs in endometrial cancer pathogenesis and treatment.


Subject(s)
Endometrial Neoplasms/genetics , Gene Expression Regulation, Neoplastic , MicroRNAs/genetics , Endometrial Neoplasms/mortality , Endometrial Neoplasms/pathology , Endometrial Neoplasms/therapy , Epithelial-Mesenchymal Transition/genetics , Female , Humans , Prognosis , RNA Interference , Treatment Outcome
14.
Case Rep Hematol ; 2014: 937203, 2014.
Article in English | MEDLINE | ID: mdl-25197583

ABSTRACT

Central nervous system (CNS) involvement in acute myeloid leukemia (AML) is a rare complication of the disease and is associated with poor prognosis. Sometimes the clinical presentation can be unspecific and the diagnosis can be very challenging. Here we report a case of CNS infiltration in a patient suffering from AML who presented with normal complete blood count and altered mental status.

15.
Dig Dis Sci ; 58(11): 3094-102, 2013 Nov.
Article in English | MEDLINE | ID: mdl-23873383

ABSTRACT

Gastrointestinal stromal tumors (GIST) represent the most common mesenchymal neoplasms affecting the gastrointestinal tract. Activating mutations in either the KIT or PDGFRa gene are the principal oncogenic triggers with the former accounting for more than 80 % of cases. In the small subset of GIST that are wild type for both the aforementioned changes, other germline or somatic mutations have been identified. GIST exhibit a highly variable clinical behavior and the main prognostic determinants are tumor size, mitotic rate, and location. It is, however, strongly believed that, beyond classic genetics, additional epigenetic phenomena such as DNA hypomethylation and hypermethylation, microRNA alterations, and chromatin modifications underlie GIST tumorigenesis and influence the clinical course and response to standard treatment. This review aims to illuminate current advances in terms of epigenetics in GIST, as well as possible implications in prognosis and therapeutics.


Subject(s)
Epigenomics , Gastrointestinal Stromal Tumors/genetics , Gastrointestinal Stromal Tumors/metabolism , Gastrointestinal Stromal Tumors/therapy , Gene Expression Regulation, Neoplastic , Genetic Predisposition to Disease , Humans
16.
Epigenetics ; 8(6): 561-70, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23760524

ABSTRACT

The term epigenetics refers to the heritable changes in gene expression that do not represent changes in DNA sequence. DNA methylation and histone modification are the best studied epigenetic mechanisms. However, microRNAs, which affect gene expression at the posttranscriptional level, should be considered as members of the epigenetic machinery too. Myelodysplastic syndromes (MDS) are clone disorders of the hematopoietic stem cell with increased risk of leukemic transformation. Over the years, increased number of studies indicates the role of epigenetic mechanisms, including microRNAs, in MDS pathogenesis and prognosis. Indeed, epigenetic therapy with demethylating agents has already been applied to MDS. In this review we summarize current knowledge on the role of epigenetic alterations in MDS pathogenesis and treatment.


Subject(s)
Epigenesis, Genetic , MicroRNAs/genetics , Myelodysplastic Syndromes/genetics , DNA Methylation , Histones/metabolism , Humans , Myelodysplastic Syndromes/drug therapy , Myelodysplastic Syndromes/etiology , Prognosis
17.
Leuk Res ; 37(3): 251-8, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23246221

ABSTRACT

Mir-17-5p and mir-20a, members of the mir-17-92 family, down-regulate E2F1, which is over-expressed in myelodysplastic syndromes (MDS). Moreover, let-7a down-regulates KRAS, which is aberrantly expressed in MDS. We evaluated the expression of the aforementioned microRNAs in CD34+ cells of 43 MDS patients using real-time PCR and their target proteins (E2F1, MYC, BCL2, CCND1, and KRAS) by Western blot. Mir-17-5p and mir-20a were under expressed in high risk MDS patients, compared to low risk MDS patients. Similarly, let-7a was under expressed in patients with intermediate or high-risk karyotype. Interestingly, there was an inverse correlation between microRNA and the expression levels of their targets. Importantly, mir-17-5p and mir-20a constitute favorable prognostic factors in MDS, since their expression was associated with increased overall survival of MDS patients.


Subject(s)
Bone Marrow Cells/metabolism , MicroRNAs/genetics , Myelodysplastic Syndromes/genetics , Aged , Aged, 80 and over , Antigens, CD34/metabolism , Bone Marrow Cells/pathology , Case-Control Studies , Female , Gene Expression Profiling , Gene Expression Regulation , Humans , Male , Middle Aged , Myelodysplastic Syndromes/diagnosis , Myelodysplastic Syndromes/metabolism , Myelodysplastic Syndromes/mortality , Prognosis
19.
Eur J Haematol ; 84(1): 1-16, 2010 Jan 01.
Article in English | MEDLINE | ID: mdl-19744129

ABSTRACT

MicroRNAs are small non-coding RNAs that act at the post-transcriptional level, regulating protein expression by repressing translation or destabilizing mRNA target. Because of their discovery, microRNAs have been associated with almost every normal cell function, including proliferation, differentiation and apoptosis. Several lines of evidence suggest that they have an important role in normal hematopoiesis as exemplified by the role of mir-155 and mir-150 in the differentiation of B and T lymphocytes, the suppressive role of mir-221 and mir-222 in erythroid differentiation, the inhibitory effect of mir-181 on hematopoietic differentiation and the induction of myeloid differentiation by mir-223. Moreover, they play a role both as oncogenes, probably by a variety of mechanisms, namely through elimination of tumor suppressor proteins, or as tumor suppressor genes by targeting oncogenic mRNAs. Their aberrant expression has been associated with solid tumors and hematopoietic malignancies as suggested by the frequent deletion of mir-15a and mir-16-1 in chronic lymphocytic leukemia, the increased levels of mir-155 in diffuse large B-cell lymphomas and the increased levels of mir-181 in acute myeloid leukemia M1 and M2. The purpose of this review is to summarize current knowledge on the role of microRNAs in normal hematopoiesis and hematopoietic malignancies and, moreover, to highlight their role as potential therapeutic tools.


Subject(s)
Gene Expression Regulation/genetics , Hematologic Neoplasms/genetics , Hematopoiesis/genetics , MicroRNAs/physiology , Animals , Cell Transformation, Neoplastic/genetics , Down-Regulation , Erythroid Precursor Cells/cytology , Gene Expression Regulation, Neoplastic/genetics , Genes, Tumor Suppressor , Hematologic Neoplasms/pathology , Humans , Invertebrates/genetics , Lymphocytes/cytology , Mice , MicroRNAs/antagonists & inhibitors , MicroRNAs/genetics , Myeloid Cells/cytology , Neoplasm Proteins/biosynthesis , Neoplasm Proteins/genetics , Oncogenes , RNA, Neoplasm/antagonists & inhibitors , RNA, Neoplasm/genetics
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