Understanding the biology of CRLF2-overexpressing acute lymphoblastic leukemia

Recent genomic analyses of childhood and adult B-precursor acute lymphoblastic leukemia (ALL) samples have identified novel genetic alterations in essential lymphoid development and signal transduction pathways, providing insight into the pathogenesis of high-risk ALL associated with treatment failure. Particular advances have been made in unraveling the genetics of ALL associated with overexpression of the cytokine receptor-like factor 2 gene (CRLF2), which is frequently accompanied by simultaneous activating mutations in genes encoding Ikaros (IKZF1), Janus kinase 1 (JAK1) and Janus kinase 2 (JAK2), and/or the IL-7 receptor alpha chain (IL7RA). Children and adults with high-risk CRLF2-overexpressing ALL have high rates of relapse and dismal overall survival. Various groups have thus attempted to characterize the biochemical consequences of these genetic lesions via preclinical models with the goal of identifying targets for new therapies. These studies provide early data suggesting the promise of signal transduction inhibitors (STIs) of the JAK/STAT and PI3K pathways for CRLF2-overexpressing ALL. Additional research efforts continue to elucidate these aberrant signaling networks to provide rationale for bringing STIs into the clinic for these high-risk patients. This review highlights the current knowledge of the incidence, prognostic significance, and biology of CRLF2-overexpressing ALL and future directions for development of targeted therapies.     

Study on the Prognostic Value of Aberrant Antigen in Patients With Acute B Lymphocytic Leukemia

BackgroundApproximately 30% to 60% of patients with acute B-lymphocytic leukemia (B-ALL) show as refractory or relapsed, which is one of the major causes of death in patients with B-ALL, but the methods of the treatment for relapsed/refractory B-ALL (R/R B-ALL) are limited. The chimeric antigen receptors redirected T cells (CAR-T cells) have showed a strong anti-leukemia role for B-ALL. About 90% of patients with R/R B-ALL treated with CD19-CAR-T cells achieved complete remission. However, 60% to 70% of patients relapsed after CAR-T cells treatment, which may be related to target antigen reduction or escape. New products are urgently needed to prevent and treat antigenic escapes causing recurrence.Patients and MethodsIn this article, we retrospectively analyzed the immunophenotype of patients with B-ALL initially diagnosed in our center from January 2010 to December 2015 to determine whether aberrant antigen expression was associated with the prognosis of patients in order to find new targets for immunotherapy.ResultsThe results show that disease-free and overall survival in patients without aberrant antigen expression were better than patients with aberrant antigen expression. The most common abnormal antigens were CD123, CD13, and CD56. Correlation analysis showed a negative correlation between aberrant CD123 expression and both disease-free and overall survival.ConclusionTherefore, in the construction of CAR-T cells in patients with R/R B-ALL, conventional CD19 can be combined with aberrant antigens such as CD123 to form CARs with bi-specific antigens or multi-specific antigens may achieve the purpose of improving efficacy. However, more clinical trials are needed.     

Philadelphia Chromosome–like Acute Lymphoblastic Leukemia

Philadelphia chromosome–like acute lymphoblastic leukemia (Ph-like ALL) is a recently described B-cell precursor ALL with a gene expression profile and a high frequency of IKZF1 gene alteration similar to that of Ph-positive ALL. Its prevalence is approximately 12% in children, 21% in adolescents (16-20 years of age), and 20% to 24% in adults older than 40 years, with a peak (27%) in young adults 21 to 39 years old. It occurs more often in male individuals and patients with Down syndrome. Ph-like ALL is overrepresented in those with Hispanic ethnicity and is associated with inherited genetic variants in GATA3 (rs3824662). It is a clinically and biologically heterogeneous subtype of B-ALL. Although most patients with Ph-like ALL have positive minimal residual disease after remission induction and poor event-free survival, approximately 40% of pediatric patients responded well to chemotherapy and can be cured with relatively low intensity of treatment. The treatment outcome correlated negatively with increasing age at presentation. Ph-like ALL is characterized by a wide range of genetic alterations that dysregulate several cytokine receptor and kinase signaling pathways, including CRLF2 rearrangement in half of the cases and translocation of nonreceptor tyrosine kinases (predominantly ABL-class and Janus kinases). Patients with ABL-class fusions respond clinically to ABL1 tyrosine kinase inhibitors, whereas mutations activating the JAK-STAT pathway are amendable to treatment with JAK inhibitors in vitro or in preclinical models. Prospective studies are needed to determine if incorporation of tyrosine kinase inhibitor targeting kinase alterations into intensive chemotherapy regimens will improve outcome of patients with Ph-like ALL.     

Coexistence of a JAK2 Mutated Clone May Cause Hematologic Resistance to Tyrosine Kinase Inhibitors in Chronic Myeloid Leukemia

Coexistence of JAK2 mutation and BCR-ABL has been rarely described. We report 3 cases with the presence of 2 different clones, 1 Philadelphia chromosome positive and the other JAK2 mutated, becoming prevalent after treatment with tyrosine kinase inhibitors (TKIs). The presence of a JAK2-positive clone may cause hematologic resistance to TKIs.Full AbstractIntroductionIn myeloproliferative neoplasms, coexistence of the JAK2 mutation and BCR-ABL rearrangement has been rarely described in patients. We report 3 such cases.Case 1Patient 1 was diagnosed as chronic myeloid leukemia (CML) following the discovery of thrombocytosis. She took imatinib with no platelet control, and hydroxyurea (HU) was added. She started nilotinib for leukocytosis, thrombocytosis, and 100% Philadelphia chromosome (Ph) positivity. In 6 months she obtained a complete cytogenetic response (CCyR), but the hematologic improvement was transient. We thus researched the JAK2 mutation that was positive. Interestingly, the JAK2^V617F was present since nilotinib start, but its expression achieved the maximum with CCyR.Case 2Patient 2 was diagnosed as primary myelofibrosis with leukocytosis, thrombocytopenia, splenomegaly, and fibrosis in the bone marrow (BM). Karyotype was normal. After 2 years with no treatment, BM showed 15% myeloblasts with 100% Ph positivity. The patient started imatinib. After an initial improvement, a new increase of leukocytes and platelets followed, with normal karyotype. HU was added, but hematologic control remained unsatisfactory and imatinib was stopped. The patient stayed on CCyR with insufficient hematologic response for more than one year, until he developed a Ph-negative myeloblast crisis with homozygosis for JAK2^V617F. We found that before imatinib the patient had a 50% JAK2-mutated phenotype, and after 3 months of therapy, more than 70%.Case 3Patient 3 was diagnosed as having essential thrombocytopenia with a normal karyotype. Good control of the thrombocytosis was obtained with HU, which continued for 10 years, and then the patient refused therapy for the next 3 years of stable disease, until he developed bone pain, leukocytosis, and enlarged spleen. Conventional cytogenetics was normal, but fluorescence in situ hybridization disclosed a 47% Ph positivity. The patient started imatinib with a rapid decrease of leukocytes; however, the platelets increased, and HU was added. After 3 months, the BM showed 7.4% Ph-positive cells. JAK2 was found mutated from imatinib start. This report suggests the presence of 2 different clones, one Ph-positive and the other JAK2 mutated and the prevalence of the latter when the former was inhibited by a tyrosine kinase inhibitor (TKI). The presence of a JAK2-positive clone may be a rare cause of hematologic resistance to TKIs.     

Clinical Impacts of Copy Number Variations in B-cell Differentiation and Cell Cycle Control Genes in Pediatric B-cell Acute Lymphoblastic Leukemia: a Single Centre Experience

BackgroundIKZF1 gene deletions have been identified as a poor prognostic factor in pediatric B-cell acute lymphoblastic leukemia (B-ALL), especially in the presence of co-occurring deletions (IKZF1^plus profile). This study aimed to determine the frequency of IKZF1 deletions and deletions in other B-cell differentiation and cell cycle control genes, and their prognostic impact in Slovenian pediatric B-ALL patients.Patients and methodsWe studied a cohort of 99 patients diagnosed with B-ALL from January 2012 to December 2020 and treated according to the ALL IC-BFM 2009 protocol. Eighty-eight bone marrow or peripheral blood samples were analysed for copy number variations (CNVs) using the SALSA MLPA P335 ALL-IKZF1 probemix.ResultsAt least one CNV was detected in more than 65% of analysed samples. The most frequently altered genes were PAX5 and CDKN2A/B (30.7%, 26.1%, and 25.0%, respectively). Deletions in IKZF1 were present in 18.2% of analysed samples and were associated with an inferior 5-year event-free survival (EFS; 54.8% vs. 85.9%, p = 0.016). The IKZF1^plus profile was identified in 12.5% of the analysed samples, and these patients had an inferior 5-year EFS than those with deletions in IKZF1 only and those without deletions (50.8% vs. 75.0% vs. 85.9%, respectively, p = 0.049). Overall survival (OS) was also worse in patients with the IKZF1^plus profile than those with deletions in IKZF1 only and those without deletions (5-year OS 76.2% vs. 100% vs. 93.0%, respectively). However, the difference between the groups was not statistically significant.ConclusionsOur results are in concordance with the results obtained in larger cooperative clinical trials. Copy number variations analysis using the SALSA MLPA kit is a reliable tool for initial diagnostic approach in children with B-ALL, even in smaller institutions in low- and middle-income countries.Key words: B-acute lymphoblastic leukemia, IKZF1 deletions, IKZF1 ^plus , MLPA, pediatric, copy number variations (CNVs)     

JAK2, CALR,and MPL Mutations in Egyptian Patients With Classic Philadelphia-negative Myeloproliferative Neoplasms

BackgroundGenetic mutations have been proven to be one of the major criteria in the diagnosis and distinction of different myeloproliferative neoplasm (MPN) subtypes. Therefore, the aim of this study was to determine the molecular profile of Egyptian patients with MPN subtypes and correlate with clinicopathological status.MethodsA series of 200 patients with MPNs (92 polycythemia vera, 68 essential thrombocythemia, and 40 primary myelofibrosis) were included in this study. DNA from each sample was amplified using polymerase chain reaction to detect Janus kinase 2 (JAK2), calreticulin (CALR), and myeloproliferative leukemia virus oncogene (MPL) mutations. Sanger sequencing was used to determine the mutation types.ResultsOf the 200 samples, 44% had JAK2V617F and 10% were carrying CALR mutation with type 2 being the most frequent type in this study (55%). No MPL or JAK2 exon 12 mutations were detected. All clinical and hematological data had no differences with other populations except that our CALR-positive patients showed a decrease in the platelet count compared with JAK2V617F-positive patients.ConclusionOur study on Egyptian patients shows a specific molecular profile of JAK2 mutation, and CALR mutation type 2 was higher than type 1.     

JAK2 V617F Mutation Status of 232 Patients Diagnosed With Chronic Myeloproliferative Neoplasms

Introduction/BackgroundThe aim of this study was to investigate the presence of Janus kinase 2 (JAK2) V617F mutation in patients with break point cluster region-abelson negative chronic myeloproliferative neoplasms (CMPNs) in our center.Patients and MethodsWe compared patients with and without the mutation, and also patients with the homozygous and heterozygous mutation, in terms of different clinical and laboratory features.ResultsThe JAK2 V617F mutation was detected in 77 (95%), 88 (68%), and 17 (77%) of polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF) patients, respectively. Among JAK2 V617F-positive patients, the homozygous genotype was found in 39 (50.6%) of the 77 PV, 23 (26.1%) of the 88 ET, and 11 (64.7%) of the 17 PMF patients. Bleeding was seen in 14 (6%) of all patients. Upper gastrointestinal bleeds were the most common, seen in 11 patients. Out of 232 CMPN patients, 44 (19%) had thrombosis. The most common thrombotic event was transient ischemic attack (52%). Progression to myelofibrosis was seen in 1 (1.2%) PV and 3 (2.3%) ET patients, and progression to acute leukemia was seen in 2 (2.5%) PV and 3 (2.3%) ET patients. Three patients with PV (3.7%), 3 with ET (2.7%), and 5 with PMF (2.7%) died during follow-up.ConclusionJAK2 V617F mutation frequencies in our PV and ET patients were similar to those reported previously. JAK2 V617F mutation frequency in our PMF patients was greater than in previous reports. All of our PV patients with thrombosis and most of our ET patients with thrombosis (76.1%) were JAK2 V617F mutation-positive. This mutation seems to be correlated with thrombosis risk.     

80例急性髓性白血病M2型患者JAK2V617F基因突变的检测及临床意义

目的 探讨JAK2V617F基因突变在急性髓性白血病M2型(AML-M2)患者中的发牛率和临床预后意义.方法 采用等位基因特异性聚合酶链反应(AS-PCR)技术,检测80例AML-M2患者的JAK2V617F基因突变情况.结果 80例AML-M2患者中,初诊时JAK2V617F基因突变6例,复发时JAK2V617F基因突变1例,JAK2V617F基因的突变率为8.8%.7例JAK2V617F基因突变者的血象和骨髓象均呈现出白血病改变特征,而无骨髓增殖性疾病(MPD)征象;免疫分型显示为髓系表达.接受治疗的5例JAK2V617F基因突变者中,有4例患者在治疗后达到完全缓解,1例未缓解;除1例失访外,其余4例患者的中位生存期为18.5个月.结论 JAK2V617F基因突变作为AML发病机制中的Ⅰ类突变,可能并不是AML发病的初始事件;初诊AML患者出现JAK2V617F基因突变也并不意味着疾病顸后较差.     

Prognostic Role of CDKN2A Deletion and p53 Expression and Association With MIPIb in Mantle Cell Lymphoma

IntroductionMantle cell lymphoma (MCL) is a rare type of lymphoma, which despite improvements in therapies in recent decades, remains an incurable disease. There is currently no reliable marker of chemoresistance available. In this study, we investigated the prognostic role of MIPIb and the association with biological markers including SOX11, p53 expression, Ki-67, and CDKN2A.Materials and MethodsThis retrospective study was focused on 23 patients with newly diagnosed classical MCL, treated at the University Hospital of Bari (Italy) between January 2006 and June 2019.ResultsWe identified a MIPIb value ≥ 5.4440 as a prognostic parameter that correlates with p53 expression and CDKN2A deletion. We also observed that patients with p53 overexpression had a significantly higher MIPIb (5.52 ± 0.53) which in 80% of patients had a value higher than 5.4440. On the other hand, CDKN2A deletion was found more frequently (75%) associated with MIPIb ≥5.4440. Only the CDKN2A deletion was associated with a higher proliferation index, with 66.7% of samples having Ki67 ≥30%. From the survival analysis we found that patients with p53 overexpression and CDKN2A deletion have a significantly worse prognosis with a median overall survival of 50 (P = .012) and 52 months (P = .018), respectively.Conclusionp53 expression and CDKN2A deletion represent a reliable pretreatment prognostic factor that identifies patients who do not benefit from currently used immunochemotherapy-based therapies and who are candidates for diversified treatments with the aim of improving prognosis. The MIPIb represents a prognostic index that correlates well with these biological alterations and can be used in clinical practice as their surrogate.     

Diagnostic Performance of Erythropoietin Levels in Polycythemia Vera: Experience at a Comprehensive Cancer Center

IntroductionConsidering the evolving diagnostic criteria of polycythemia vera (PV), we analyzed the utility of serum erythropoietin (EPO) as a predictive marker for differentiating polycythemia vera (PV) from other etiologies of erythrocytosis.Patients and MethodsWe conducted a retrospective study after a review of electronical medical records from January 2005 to December 2016 with diagnosis of erythrocytosis using International Classification of Disease–specific codes. To evaluate the diagnostic performance of EPO levels and JAK2-V617F mutation, we constructed a receiver-operated characteristic curve of sensitivity versus 1-specificity for serum EPO levels and JAK2-V617F mutation as predictive markers for differentiating PV from other causes of erythrocytosis.ResultsWe surveyed 577 patients with erythrocytosis. Median patient age was 59.2 years, 57.72% (n = 329) were male, 86.3% (n = 491) were white, and only 3.3% (n = 19) were African American. A total of 80.88% (n = 351) of those diagnosed with PV had a JAK2-V617F mutation compared to only 1.47% (n = 2) whose primary diagnosis was secondary polycythemia. When comparing JAK2-V617 mutation to the EPO level, the area under the curve of JAK2-V617 (0.8970) was statistically larger than that of EPO test (0.6765). Therefore, the PV diagnostic methodology using JAK2-V617 is better than the EPO test. An EPO level of < 2 mIU/mL was > 99% specific to predict PV but was only 12% sensitive.ConclusionIn the appropriate clinical setting, cytogenetic and molecular studies such as JAK2 mutation status prevail as the most useful tools for PV case identification. The use of isolated EPO to screen patients with erythrocytosis is not a good diagnostic approach.     

伴有JAK2 V617F突变的慢性中性粒细胞白血病1例并文献复习

目的:探讨伴有JAK2基因V617F突变的慢性中性粒细胞白血病(CNL)的实验室特征。方法:通过骨髓涂片进行细胞形态学分析诊断;采用实时荧光定量PCR方法检测BCR-ABL融合基因;实时荧光定量PCR方法及DNA测序方法检测JAK2 V617F突变;RHG显带进行常规染色体核型分析。结果:细胞形态学诊断为慢性中性粒细胞白血病;BCR/ABL融合基因为阴性;存在JAK2 V617F杂合突变;染色体分析结果为正常核型。结论:JAK2 V617F突变在慢性中性粒细胞白血病中很少见,具有该突变的CNL患者有较长的生存期,JAK2 V617F突变可能提示预后良好。     

Prognostic Effect of Complex Karyotype,Monosomal Karyotype,and Chromosome 17 Abnormalities in B-Cell Acute Lymphoblastic Leukemia

BackgroundThe effect of monosomal karyotype (MK), complex karyotype (CK), and chromosome 17 abnormalities (abnl 17) on prognosis in B-cell acute lymphoid leukemia (B-ALL) has not yet been established.Patients and MethodsWe conducted a retrospective analysis of prognostic factors on 237 adult patients with B-ALL treated at our institution.ResultsOlder age (older than 60 years), higher white blood cell count (> 30), and abnl 17 were associated with shorter overall survival in univariate analysis, but multivariable analysis only identified older age as an independent poor prognostic actor. There was a significant correlation between abnl 17 and older age.ConclusionIn contrast to the patients with acute myeloid leukemia, our results show that MK and CK do not play a predictive role in patients with B-ALL, but further study is required to determine whether specific changes on chromosome 17 might have prognostic value when investigated separately.     

伴有JAK2 V617F突变的慢性中性粒细胞白血病1例并文献复习

目的：探讨伴有JAK2基因V617F突变的慢性中性粒细胞白血病（CNL）的实验室特征。方法：通过骨髓涂片进行细胞形态学分析诊断;采用实时荧光定量PCR方法检测BCR-ABL融合基因;实时荧光定量PCR方法及DNA测序方法检测JAK2 V617F突变;RHG显带进行常规染色体核型分析。结果：细胞形态学诊断为慢性中性粒细胞白血病;BCR/ABL融合基因为阴性;存在JAK2 V617F杂合突变;染色体分析结果为正常核型。结论：JAK2 V617F突变在慢性中性粒细胞白血病中很少见,具有该突变的CNL患者有较长的生存期,JAK2 V617F突变可能提示预后良好。     

Tissue microarray-based study of patients with lymph node-negative breast cancer shows that HER2/neu overexpression is an important predictive marker of poor prognosis

BackgroundDespite good prognosis in most cases of lymph node (LN)-negative breast cancer, individual patients may have markedly different clinical outcomes. Here, we investigated the prognostic significance of HER2/neu overexpression in these tumors.Materials and methodsWe employed a tissue microarray to examine HER2/neu overexpression by immunohistochemical staining in 359 consecutive patients diagnosed with LN-negative breast cancer, who underwent surgery from January 1993 to December 1998.ResultsHER2/neu overexpression was detected in 81 of 359 (23.1%) patients. The 10-year disease-free survival (DFS) values (81.2% versus 61.8%, P value 0.000) and overall survival (OS) rates (85.7% versus 63.9%, P value 0.000) were significantly different between cases with HER2/neu-negative or HER2/neu-positive tumors. After multivariate analysis, HER2/neu status and tumor size were identified as independent prognostic factors for 10-year OS. Moreover, HER2/neu overexpression was significantly associated with poorer clinical outcomes in an intermediate-risk group identified by the St Gallen classification (10-year DFS, 79.6% versus 61.8%, P value 0.000; 10-year OS, 84.7% versus 63.9%, P value 0.000).ConclusionsOur results show that HER2/neu overexpression is an important independent prognostic factor for LN-negative breast cancer cases and support the theory that more intensive adjuvant chemotherapy is required in the population with HER2/neu overexpression.     

Low leukemia burden improves blinatumomab efficacy in patients with relapsed/refractory B-cell acute lymphoblastic leukemia

Background

A lower baseline bone marrow blast percentage (bBMB%) is associated with better outcomes in patients with B-cell acute lymphoblastic leukemia (B-ALL) receiving blinatumomab. The objective of this analysis was to investigate the association between bBMB% and treatment outcomes in relapsed/refractory (R/R) B-ALL.

Methods

Data from five trials of blinatumomab for R/R B-ALL were pooled for analyses. Patients were placed in one of three groups: group 1, ≥50% bBMBs; group 2, ≥25% to <50% bBMBs; group 3, ≥5% to <25% bBMBs. Response and survival outcomes were compared between groups.

Results

Data from 683 patients (166 pediatric, 517 adult) were analyzed. Collectively, patients in groups 2 and 3 had significantly higher odds of achieving a complete remission (CR) (odds ratio [OR], 3.50 [95% confidence interval (CI), 2.23–5.48] and 3.93 [95% CI, 2.50–6.18], respectively; p < .001) and minimal/measurable residual disease response (OR, 2.61 and 3.37, respectively; p < .001) when compared with group 1 (reference). Groups 2 and 3 had a 37% and 46% reduction in the risk of death (hazard ratio [HR], 0.63 and 0.54, respectively; p < .001) and a 41% and 43% reduction in the risk of an event (relapse or death) (HR, 0.59 and 0.57, respectively; p < .001) compared with group 1. No significant differences in response or survival outcomes were observed between groups 2 and 3. Seven of nine patients whose bBMB% was lowered to <50% with dexamethasone achieved CR with blinatumomab.

Conclusion

Any bBMB% <50% was associated with improved efficacy following blinatumomab treatment for R/R B-ALL.     

No Differences in Outcomes Between JAK2 V617F–Positive Patients with Variant Allele Fraction < 2% Versus 2-10%: A 6-Year Province-wide Retrospective Analysis

IntroductionJAK2 V617F mutation is one of the major criteria in the diagnosis of myeloproliferative neoplasms (MPN) and its variant allele fraction (VAF) determines the disease phenotype and outcomes. This study aimed to define characteristics and outcomes of patients with JAK2 V617F VAF < 2% compared to patients with VAF 2%-10%.Patients and MethodsWe included 5079 patients with JAK2 V617F tested during 2010-2015 and identified 216 patients (4.3%) with JAK2 V617F VAF < 10%. Twenty-seven patients were excluded because of missing follow-up data.ResultsA total of 189 patients were included for final analysis (89 patients with VAF < 2% and 100 patients with VAF 2%-10%). Patients with JAK2 V617F 2%-10% VAF had a significantly higher rate of splenomegaly, higher platelet counts, and more MPN diagnoses than the group with VAF < 2%. Ten patients (10.0%) with VAF 2%-10% and 24 patients (27.0%) with VAF < 2% had normal blood count and no thrombosis. There were no differences between the groups in all outcomes, including thrombotic complications (18.0% in both groups), progression to hematologic or solid cancers, and death. Patients without hematologic diagnosis had similar thrombotic incidence (16.7% in VAF < 2% vs. 20.0% in VAF 2%-10%).ConclusionPatients with JAK2 V617F mutation VAF < 2% have similar survival and thrombotic incidence as patients with VAF 2%-10%. Patients with low VAF should be monitored in the same manner as patients with higher VAF with the same diagnoses to prevent morbidity and mortality. Patients without hematologic diagnosis may benefit from thrombotic risk reduction strategies such as optimization of cardiovascular risk factors.     

Most pediatric patients with essential thrombocythemia show hypersensitivity to erythropoietin in vitro, with rare JAK2 V617F-positive erythroid colonies

Essential thrombocythemia (ET), a Philadelphia (Ph) chromosome negative chronic myeloproliferative disorder, is usually a disease of middle age and it is extremely rare in pediatric patients. In this report we studied 12 children diagnosed with ET and one child with thrombocytosis and family history of ET. We failed to detect JAK2 V617F mutation either in peripheral blood leukocytes or in separated platelets and granulocytes. Monoclonal hematopoiesis was noted in only one female patient. Erythroid progenitors of most of the patients displayed hypersensitivity to erythropoietin (Epo) in vitro; Epo-independent erythroid colonies (EECs) were detected in seven patients. Among EECs of three patients we observed rare colonies heterozygous or homozygous for the JAK2 V617F mutation. Our data suggest that childhood ET patients could bear minor JAK2 V617F-positive subclones.     

Clinical Implication of Toll-Like Receptors (TLR2 and TLR4) Polymorphisms in Adult Patients with Acute B-cell Lymphoblastic Leukemia

Backgrounds: Neutropenia after intensive chemotherapy of acute lymphoblastic leukemia (ALL) could lead to infectious complications that affect outcome of acute leukemia patients. Many single-nucleotide polymorphisms (SNPs) of Toll-like receptors (TLRs) can affect the genetic susceptibility to infections. We investigated the impact of different SNPs on the incidence of developing sepsis and pneumonia in patients with newly diagnosed B-ALL following induction chemotherapy. Subjects and methods: We analyzed three SNPs in the TLR2 (Arg753Gln) and TLR4 (Asp299Gly& Thr399Ile) genes using polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) in a case control study of 40 precursor B-ALL patients and 50 control subjects. The risk of developing sepsis and pneumonia were assessed by multiple logistic regression analyses. Results: The presence of the TLR-2 AG polymorphism was significantly associated with pneumonia in B-ALL patients. Furthermore, TLR4 Thr399Ile AG was a risk factor for sepsis in B-ALL patients. Moreover; Significant association between TLR-2 AA, TLR-4 CC and TL-4 AA genotypes and longer OS were detected in studied B-ALL patients. Conclusion: We concluded that TLR-4 (AG and CT) genotypes are associated with high susceptibility to sepsis and pneumonia respectively; while, TLR-2, TLR-4 AA and TLR-4 CC genotypes  could predict good B-ALL patients outcome.