Pathogenesis of Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is a hematological malignant disease characterized by an enhanced self-renewal ability of precursor lymphoid cells whose cell division takes more time than their normal counterparts. ALL occurs most between 2 to 5 years of age and during the sixth decade of life. There is a strong relationship between the time ALL occurs in children and the genetic abnormalities which are identified by the rate of leukemic concordance between identical twins.About 90% of ALL cases do not have a clear etiological mechanism. Genetic syndromes, polymorphic variants genes, germline mutations, and some environmental factors are responsible for less than 10% of ALL predisposition but the pathogenesis mechanism of ALL is not identified precisely.Here we review the recent findings and earlier studies about the pathogenesis of acute lymphoblastic leukemia and its incidence. This article also summarizes the identification of predictive factors for ALL and options available to predict disease recurrence

Complete Genotype and Clinical Phenotype of Hemophilia B: A Study on Iranian Patients

Background: Hemophilia B which refers to the deficiency or functional defect of factor IX (FIX) is typically an X-linked bleeding condition that arises from heterogeneous mutations of the FIX gene (F9). The number of hemophilia cases in Iran is considerable and currently, about 1118 Iranian patients are suffering from hemophilia B, although a small number of them underwent genetic investigations. Here we assessed molecular defects and also laboratory and clinical findings of 10 Iranian cases with hemophilia B. Materials and Methods: A total of 10 cases with hemophilia B were enrolled in the study. Patients were clinically examined by a hematologist and their previous medical documents were surveyed carefully. Routine coagulation tests and FIX activity and antigen assays were performed for the studied patients. Genotyping of F9 for identifying genetic mutations was conducted by the Sanger sequencing method following PCR amplification of the promoter region and all the eight exons of the F9 gene. Results: The mean age of patients was 4 years (9 months to 16 years) and consanguinity was reported in 80% of cases. Patients were commonly manifested by hematoma (90%), epistaxis (80%), and hemarthrosis (70%) and the severity of the disorder was severe (70%) or moderate (30%). In nine out of 10 patients a genetic defect in F9 gene we detected including three missense (c.304T>C, c.1007T>A, c.191G>A) and three nonsense mutations (c.892C>T, c.880C>T, c.1113C>A). Based on the FIX variant database (http://www.factorix.org), five mutations have been reported previously, but mutation c.1007T>A (p.Ile336Asn) seems to be a novel mutation. Conclusion: Our results indicated the heterogeneous molecular defects of hemophilia B in Iran, as recorded in the FIX mutation database. Moreover, no specific genotype-phenotype association was observed in studied subjects

Detection of nucleophosmin and FMS-like tyrosine kinase-3 gene mutations in acute myeloid leukemia

Background and Objectives : Nucleophosmin gene mutations are frequently reported in acute myeloid leukemia (AML) patients with normal karyotype, which is also frequently associated with internal tandem duplication mutations in the FMS-like tyrosine kinase-3 gene. We sought to detect the nucleophosmin and FMS-like tyrosine kinase-3 (FLT3) internal tandem duplication (ITD) mutations among Iranian patients with AML and to assess the relationship between these mutations and the subtypes of the disease. Design and Setting : Cross-sectional study of patients referred during 2007 through 2009. Patients and Methods : Bone marrow and peripheral blood samples of 131 AML patients were randomly collected at the time of diagnosis and prior to treatment and the DNA extracted. After amplifying the nucleophosmin and FLT3 gene regions, positive cases were screened by conformation-sensitive gel electrophoresis and agarose gel electrophoresis techniques. Results : Of 131 patients, 23 (17.5%) (0.95% CI=0.107-0.244) had nucleophosmin gene mutations. The highest frequency of such mutations was found among the subtypes of M4 (30.4%), M3 (21.7%) and M5 (17.4%). There was a high frequency of these mutations in the M3 subtype as well as a high frequency of allele D in all subtypes. Also, 21 (16.0%) samples (0.95% CI=0.092-0.229) had FLT3/ITD mutation, of which 8 samples had mutant nucleophosmin (8 of 23, 35%), and another 13 samples had wild-type nucleophosmin gene (13 of 108, 12%). There was a high degree of association between the occurrence of nucleophosmin and FLT3/ITD mutations (P=.012). Conclusion : Our data showed a high frequency of NPM1 mutations in the monocytic subtypes of AML, as well as a high degree of association between the occurrence of NPM1 and FLT3/ITD mutations

Inhibitor in Congenital Factor VII Deficiency; a Rare but Serious Therapeutic Challenge—A Systematic Literature Review

Background: Congenital factor (F) VII deficiency is a rare coagulation factor deficiency with an estimated incidence of 1 per 500,000 individuals. Patients with severe FVII deficiency present a broad range of clinical presentations. Alloimmunization against exogenous FVII, as the main challenge of replacement therapy, is an extremely rare phenomenon that is accompanied by a high rate of life-threatening bleeding, that renders replacement therapy less effective. Due to the importance of the issue, we performed a systematic literature review in order to assess incidence, molecular basis, clinical presentations, and therapeutic challenge and management of inhibitor in congenital FVII deficiency. Strategy of search: This systematic review was performed in accordance with PRISMA guidelines. We performed an English-language literature review in the PubMed, EMBASE, Scopus, and Google Scholar databases, using the following keywords: “factor VII inhibitor”, “factor VII inhibitors”, “FVII inhibitors”, “congenital FVII deficiency”, “recombinant factor VII”, “anti rFVIIa”, “replacement therapy”, and “alloantibody”. Results: Out of 380 patients in the 13 studies, 27 had inhibitor against FVII; 18 were male, 7 were female, while the sex of 2 was not stated. The majority (92%) developed a high-titer inhibitor (Bethesda Unit > 5). All patients had severe FVII deficiency (FVII:C < 10%), and the majority received recombinant FVII prior to inhibitor development (N: 24, 89%). Among ten patients with a detected mutation, three subjects had a common non-sense (30%), and two had a deletion (20%). Conclusions: Inhibitor development is a relatively rare phenomenon seen only in severe FVII deficiency, where it is associated with severe and life-threatening presentations, treatment challenge, and economic burden on the patients and their families

Inhibitor in Congenital Factor VII Deficiency; a Rare but Serious Therapeutic Challenge—A Systematic Literature Review

Background: Congenital factor (F) VII deficiency is a rare coagulation factor deficiency with an estimated incidence of 1 per 500,000 individuals. Patients with severe FVII deficiency present a broad range of clinical presentations. Alloimmunization against exogenous FVII, as the main challenge of replacement therapy, is an extremely rare phenomenon that is accompanied by a high rate of life-threatening bleeding, that renders replacement therapy less effective. Due to the importance of the issue, we performed a systematic literature review in order to assess incidence, molecular basis, clinical presentations, and therapeutic challenge and management of inhibitor in congenital FVII deficiency. Strategy of search: This systematic review was performed in accordance with PRISMA guidelines. We performed an English-language literature review in the PubMed, EMBASE, Scopus, and Google Scholar databases, using the following keywords: “factor VII inhibitor”, “factor VII inhibitors”, “FVII inhibitors”, “congenital FVII deficiency”, “recombinant factor VII”, “anti rFVIIa”, “replacement therapy”, and “alloantibody”. Results: Out of 380 patients in the 13 studies, 27 had inhibitor against FVII; 18 were male, 7 were female, while the sex of 2 was not stated. The majority (92%) developed a high-titer inhibitor (Bethesda Unit > 5). All patients had severe FVII deficiency (FVII:C < 10%), and the majority received recombinant FVII prior to inhibitor development (N: 24, 89%). Among ten patients with a detected mutation, three subjects had a common non-sense (30%), and two had a deletion (20%). Conclusions: Inhibitor development is a relatively rare phenomenon seen only in severe FVII deficiency, where it is associated with severe and life-threatening presentations, treatment challenge, and economic burden on the patients and their families

Oncogenic RAS genes impair erythroid differentiation of erythroleukaemia cells

RAS mutations occur frequently in acute myeloid leukaemia and myelodysplasia, suggesting a functional role for this oncogene in leukaemogenesis. We show here, for the first time, that both N-RAS and H-RAS can impair erythroid differentiation of erythroleukaemia cells induced with hexamethylene bisacetamide. Transformation by RAS allowed extended proliferation in the presence of inducer and also inhibited maturation as measured by impaired haemoglobinization and reduction in cell size. These data provide an interesting counterpoint to the effect of mutant RAS on monocytic cells, where it has a potentiating effect on differentiation and may indicate a causal link between the activation of RAS and erythroid lineage dysplasia in preleukaemia

Assesment Of The Efficacy Of HESA-A On The Proliferation And Apoptosis Of Chronic Myelogenous Leukemia Cell Line(K562)

Background and Aim: Chronic myelogenous leukemia is characterized by Philadelphia (Ph) chromosome, the presence of BCR-ABL fusion gene and constitutive activation of the ABL1 tyrosine kinase. Despite an excellent result of target therapy by imatinib, some patients develop resistance to imatinib. In this study Efficacy of HESA-A on proliferation and apoptosis of K562 cell line was assessed. Materials and Methods: In this study doubling time of K562 cell line was calculated. The cells were affected by various concentrations of HESA-A(1,2,4 and 8 mg/ml respectively). Cytotoxicity and IC50 dose of HESA-A were detected by MTT and trypan blue exclusion assay. Apoptosis was assessed by flowcytometry after 48 h cell treatment in the presence of IC50 dose. Results: Doubling time of K562 cells was 24 hours. HESA-A reduced the number of viable K562 cells in a concentration dependent manner.IC50 dose was 3.5 mg/ml. In flowcytometry analysis of apoptosis, 19.22% of the treated cells were located in the position of the necrotic cells. Conclusion: The results of MTT and trypan blue exclusion assay suggest that HESA-A inhibits the growth of k562 cells in a concentration dependent manner and induces necrosis in K562 cells

Cytotoxic Effects Of Selective Inhibitor ‘Aurora Kinase B’ On Viability And Metabolic Features Of Human Promyelocytic Leukemia Cell Line

Background and Aim: A goal of modern cancer research is to reach targeted therapies with drugs having fewer side effects. AZD1152 is a highly specific inhibitor of Aurora Kinase B, which leads to the programmed cell death by different mechanisms. The aim of this study was to evaluate the effects of AZD1152 on viability and metabolic activity of NB4 cells (APL derived cell line).  Materials and Methods: The cells were treated with various concentrations of AZD1152. After 24, 48 and 72h treatments, the metabolic activity and viability of inhibitor-treated NB4 cells were assessed using MTT and trypan blue dye exclusion assays, respectively. Data were analyzed by applying student’s t-test (Microsoft Excel).  Results: A t&nbsp;25, 50 and 100 nM, AZD1152 reduced the metabolic activity by 9.2, 15.5 and 56.2% (after 24h), 10.3, 19.5 and 59.9% (after 48h), and 17.1, 28.4 and 64.8% (after 72h), respectively. Meanwhile, the percentage of viability was decreased&nbsp;to about 51, 45 and 40% (after 24h), 39, 36 and 30% (after 48h), and 34, 32 and 28% (after 72h), respectively.  Conclusion : According to the results, AZD1152 has substantial efficacy on APL cell line and may be applied in some cases, e. g., for patients who have relapse or who become refractory to the conventional chemotherapy. Further studies are needed to show the molecular mechanisms regulating effects of this anti-cancer agent