Expression In Acute Leukemia Research Articles

High PD-L1 Expression May be Associated with Worse Overall Prognosis in Acute Myeloid Leukemia

Background: PD-L1 expression has been explored in solid tumours and in classical Hodgkin's lymphoma, however its expression in acute leukemias has been minimally studied. PD-L1 over-expression in AML blasts has previously been associated with worse outcomes in patients with mutated FTL3 genes, and positively correlated with TP53 expression. Over-expression of PD-L1 may contribute to failed response to hypo-methylating agents, leading to the rationale behind combination therapy with immune-checkpoint inhibitors. Despite evidence that the PD-1/PDL-1 axis may promote myeloid neoplasms by modulating immune escape, clinical trials studying the role of immunotherapy in MDS/AML have produced disappointing results. The lack of evidence to support the role of PD-1-targeted therapy in AML may be due to lack of identification of the subset of patients who may benefit from immunotherapy. We previously demonstrated that PD-L1 expression is significantly enhanced in patients with JAK2/STAT mutations compared to patients with wild-type (WT) JAK2/STAT. Here, we investigate the clinical correlate of our findings and compare clinical outcomes of AML patients with respect to PD-L1 expression. Methods: Immunohistochemical staining for PD-L1 was previously performed on bone marrow biopsies of 31 AML patients, including 11 patients with JAK2/STAT mutations (nine with JAK2 V617F exon 14 mutations, one with JAK2 I540-E543delinsRG exon 12 mutation and one with STAT5B N642H mutation) and 20 patients with WT JAK2/STAT. PD-L1 CPS was calculated by summation of all PD-L1-stained cells divided by total number of tumour cells, and multiplied by 100. Retrospective chart review was performed to extract data regarding patient demographics, cytogenetics, mutations, treatment course, as well as clinical outcomes. Low and high PD-L1 expression was defined as CPS score <10 and > 20 respectively. Kaplan-Meier analysis was used for analysing overall survival (OS) and event-free survival (EFS), with statistical significance determined using a 2-tailed log-rank test. EFS was defined as duration of time between diagnosis and the first occurrence of either going off protocol induction without achieving complete remission (CR), relapse from CR, or death due to any cause. Patients who were alive at the time of study analysis were censored at date of last follow-up. Results: A total 15 patients demonstrated high PD-L1 expression (lowest PD-L1 CPS 20), including four patients with WT JAK2/STAT and all 11 patients with mutant JAK2/STAT. 16 patients demonstrated low PD-L1 expression (highest PD-L1 CPS 6). Only three patients in the low PD-L1 expression group never achieved complete remission compared to eight patients in the high PD-L1 expression group. Median OS in the low PD-L1 expression group was significantly longer than median OS in the high PD-L1 expression group (29.1 months [95% CI 1.4-7.2] vs 9.3 months [95% CI 0.1-0.7]; HR 2.4 [95% CI 1.1-5.6], p = 0.0253, Figure 1). Similarity, EFS was significantly longer in the low PD-L1 expression group (13.1 months [95% CI 1.3-6.7] vs. 4.4 months [95% CI 0.1-0.8]; HR 2.4 [95% CI 1.1-5.6], p = 0.0253). When analysis was separated by European LeukemiaNet (ELN) risk stratification, significant differences in OS and EFS were re-demonstrated in patients with favourable ELN risk, but not in patients with intermediate or adverse risks. When wild-type JAK2/STAT patients were analyzed separately, there was no significant differences between OS and EFS with respect to PD-L1 expression. Conclusions: We previously demonstrated that PD-L1 is significantly up-regulated in AML patients who carry mutant JAK2/STAT when compared to WT JAK2. Using a proposed PD-L1 CPS cut-off score of 20, we demonstrated that high PD-L1 expression was associated with significantly worse outcomes with respect to OS and EFS. These results may indicate a therapeutic role of immunotherapy in the treatment of AML, particularly in patients with JAK2/STAT mutations.

First-in-Human Phase I Trial Combining Biologically Guided Radioimmunotherapy (RIT) Using a 90Y-Anti-CD25 Monoclonal Antibody (Mab) with CT-guided Total Marrow and Lymphoid Irradiation (TMLI) in Relapsed and Refractory (R/R) Acute Leukemia

Patients with R/R acute leukemia after allogeneic hematopoietic cell transplant (alloHCT) have a dismal prognosis with 3-year survival rates of < 20%. To improve outcomes, innovative targeted forms of organ sparing radiotherapy, such as tumor-specific RIT and TMLI, are needed to dose escalate with acceptable toxicities, especially in patients ≥ age 60 years who cannot tolerate total body irradiation (TBI) / myeloablative regimens and who have a poor prognosis. CD25 is an ideal RIT target given its expression in acute leukemias, association with poor prognosis, and expression by leukemia stem cells. In this phase I trial (NCT05139004) we hypothesized that combining dose escalated 90Y-anti-CD25 RIT with fixed dose TMLI 12 Gy, fludarabine (flu), and melphalan (mel) in patients with R/R disease is safe and associated with acceptable toxicities. The primary objective of this trial is to determine the maximum tolerated dose and recommended phase 2 dose of 90Y-anti-CD25 Mab (Day -15) with 12 Gy TMLI (1.5 Gy twice a day, days -8 to -5), flu (30 mg/m2/d days -5 to -2), and mel (100 mg/m2, day -2) in patients ≥ 60 years old or with a HCT-comorbidity index ≥ 2 and with R/R AML, ALL or myelodysplastic syndrome (MDS) scheduled to undergo alloHCT from a matched donor. TMLI mean organ dose constraints for kidney, lung and liver were 4 Gy. Planned dose levels of 90Y-anti-CD25 were 0.3, 0.4, and 0.5 mCi/kg. 111In-anti-CD25 (5 mCi) was co-infused followed by serial nuclear scans to assess dosimetry and biodistribution. To date 5 patients (ages 31-74) with R/R AML have been treated. Marrow and circulating blasts ranged from 10-36% and 9-44%, respectively. For the 3 patients at 0.3 mCi/kg, follow-up ranged from 89-191+ days. 90Y/111In-anti-CD25 nuclear scans demonstrated persistent uptake in bone out to 144 hours, which was associated with a decline in circulating blasts. After combined RIT and TMLI, mean doses (Gy) to lungs ranged from 5.7-6.5, to kidneys from 7.5-8.2 and to liver from 7.2-11.6. No dose-limiting toxicities (DLT) were observed. All 3 patients achieved CR on day +30 bone marrow biopsies and 2 remained in CR on day +90 biopsies. Two patients have recently been treated at the 0.4 mCi/kg dose level. The results of patients treated at the higher dose levels will be provided. Dose escalation by adding 90Y-anti-CD25 RIT at 0.3 mCi/kg to 12 Gy TMLI was safe, including in older patients, with no dose-limiting toxicities, mean critical organ doses lower than conventional myeloablative TBI, and encouraging response rates. The toxicity profile and dose estimates at 0.3 mCi/kg predict that the planned higher dose levels will also be feasible with acceptable toxicities. RIT and TMLI are complementary and when combined address the limitations of each modality. Combining these targeted therapies may be a superior strategy to intensify dose to leukemia compared to dose escalation of either modality alone.

Aberrant antigen expression in acute leukemia: A single center study in Saudi Arabia

Aberrant antigen expression in acute leukemia: A single center study in Saudi Arabia

Aberrant antigenic expression in acute leukemia: Study from a tertiary care center in Southern India

Objectives: Aberrant antigenic expression in acute leukaemia is an expression of antigens which is not normally associated with acute leukaemia of that specific lineage and does not fulfil the criteria for diagnosis of Mixed phenotype acute leukaemia (MPAL). This aberrant immunophenotype can be used for the assessment of measurable residual disease (MRD) and sometimes may predict certain genetic events. Material and Methods: This was a cross-sectional study conducted in a tertiary care centre in Southern India over two years to assess the type and frequency of aberrant antigen expression in acute leukaemia by multiparameter flow cytometry. All routine cases of acute leukaemia confirmed by flow cytometric immunophenotyping were enrolled. Results: Among 244 acute leukemia cases, 84 (34%) B-ALL, 28 (11%) T-ALL, 124 (51%) AML and 8 (3%) MPAL were found. Aberrant antigenic expression was seen in 17 (20%) B-ALL, 5 (18%) T-ALL, 33 (27%) AML and 1(12.5%) MPAL. Most common aberrancy in AML was CD7(70.3%) followed by CD19 (13.5%) and CD79a (10.8%), in B-ALL was CD33(52.6%) followed by CD13 (10.5%) and CRLF2 (10.5%) and in T-ALL were CD33 and CD 79a (40% each). Conclusion: B-ALL showed a greater heterogeneity in aberrant antigens compared to AML and T-ALL. The future implication of this study is that aberrant markers can help in monitoring measurable residual disease Some aberrant phenotypes may indicate the presence of a genetic event or may be of prognostic significance. Some aberrant antigens may also be used as therapeutic targets.

Detection of CSRP2 Transcript Levels By Real-Time Quantitative PCR May be a Useful Tool for Monitoring Minimal Residual Disease in B-Cell ALL

Introduction Cysteine and glycine-rich protein 2 (CSRP2) is gaining increasing attention as a therapeutic target due to its high expression in acute leukemias and its involvement in the development of cancer. However, whether it can be used as a reliable marker for minimal residual disease (MRD) remains unknown.Methods A total of 155 adult B-cell acute lymphoblastic leukemia (ALL) patients who received at least two cycles of consolidation chemotherapy were enrolled. Their leukemia-associated aberrant immune phenotypes (LAIPs) and CSRP2 transcript levels at the second consolidation chemotherapy (CON2) were detected by flow cytometry (FCM) and real-time quantitative reverse transcriptase-polymerase chain reaction (RQ-PCR). According to our published work, 1.80% and 0.01% were set as the positive threshold of CSRP2 transcript level and the FCM test for diagnosis, respectively. Pearson correlation coefficient was calculated to describe the relationship between the CSRP2 transcript level and the FCM test. Competing risk model and Cox proportional hazard regression model were conducted to estimated associations between the CSRP2 transcript level at CON2 and the prognosis.Results The median CSRP2 transcript level of all 155 patients was 0.2% (0.02%-108.17%). Among them, 108 patients were negative for both FCM and CSRP2, and 8 patients were positive for both FCM and CSRP2. The coincidence rate was 74.84%. There was a significant positive correlation between FCM and CSRP2 (r=0.73, 95% CI 0.64-0.79; P <0.001)(Figure 1a).Patients were divided into a high CSRP2 group (N=17) and a low CSRP2 group (N=138) based on the transcript level of 1.00% settled by the ROC curve. Nine of 17 patients with high transcript level of CSRP2 suffered from leukemia relapse during the follow-up. Moreover, among the nine relapse patients, three patients had positive CSRP2 and negative FCM at CON2. In univariate analysis, patients with high CSRP2 transcript level showed a significantly lower 5-year leukemia-free survival (LFS) (33.0% vs. 48.6%, P =0.014) and 5-year survival (OS) (28.6% vs. 72.5%, P <0.001), higher 5-year cumulative incidence of relapse (CIR) (60.6% vs. 47.3%; P =0.042) (Figure 1b-d). Variates with P-value lower than 0.1 including BCR-ABL1(Y/N), treatment (chemotherapy only vs. allo-HSCT), CSRP2 transcript level (high vs. low), WBC (≥ vs. < 53.6×10E+9/L [settled by ROC curve]), were put into multivariate analysis. In multivariate analysis, no BCR-ABL1 (LFS, HR 0.43, 95% CI 0.26-0.71, P =0.001; OS, HR 0.41, 95% CI 0.21-0.81, P =0.010; CIR, HR 0.39, 95% CI 0.22-0.68, P =0.001), allo-HSCT (LFS, HR 0.29, 95% CI 0.17-0.51, P < 0.001; OS, HR 0.21, 95% CI 0.11-0.42, P <0.001; CIR, HR 0.29, 95% CI 0.17-0.50, P <0.001), and low CSRP2 (LFS, HR 0.37, 95% CI 0.19-0.74, P =0.005; OS, HR 0.21, 95% CI 0.10-0.44, P <0.001; CIR, HR 0.44, 95% CI 0.21-0.93, P =0.031) were independently associated with higher LFS, OS and lower CIR.Conclusions Our study suggested that patients with a high CSRP2 transcript level at CON2 had poor survival and was an independent risk factor for relapse. The transcript level of CSPR2 at CON2 may be a valuable marker to complement the MRD assessment system and improve the number of evaluable patients. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Relationship of CD4 and CD34 Expression in Acute Leukemia

Relationship of CD4 and CD34 Expression in Acute Leukemia

A Real-world Perspective of CD123 Expression in Acute Leukemia as Promising Biomarker to Predict Treatment Outcome in B-ALL and AML

IntroductionCD123 is overexpressed in many hematologic malignancies and found to be useful in characterizing leukemic blasts of both acute myeloid leukemia (AML) and B-acute lymphoblastic leukemia (B-ALL). CD123 has been recently found to be a marker of leukemic stem cells, and its utility to measure residual disease and potential role in disease relapse is under evaluation. Materials and MethodsHerein, we have evaluated the expression of CD123 in 757 samples of acute leukemia including 479 treatment-naive and 278 follow-up samples and compared with post-induction morphologic complete remission and measurable residual disease (MRD) status. Multiparametric flow cytometry was used for assessment of CD123 expression and immunophenotypic characterization of leukemic blasts at diagnostic and MRD assessment time points. ResultsUsing variable cutoffs of 5%, 10%, and 20% to define a case as CD123-positive, expression of CD123 was observed in 75.6%, 66.2%, and 50% of AML and 88.6%, 81.8%, and 75% of B-ALL, respectively. Of 11 patients, 7 (63.63%) had mixed phenotype acute leukemia, but none of the 12 patients with T-acute lymphoblastic leukemia showed positivity for CD123. CD123 expression at diagnosis was associated with post-induction MRD-positive status in both B-ALL (P < .001) and AML (P = .001). We also evaluated the utility of CD123 as a leukemia-associated aberrant immunophenotype and found it to be useful in both patients with AML (baseline, 50.6%; follow-up, 53%) and B-ALL (baseline, 75%; follow-up, 73.07%). ConclusionsIn conclusion, CD123 may be considered as a cardinal marker for residual disease assessment and response evaluation in AML and B-ALL.

KLF1/EKLF expression in acute leukemia is correlated with chromosomal abnormalities

KLF1 (EKLF) is a master regulator of erythropoiesis and controls expression of a wide array of target genes. We interrogated human tissue microarray samples via immunohistological analysis to address whether levels of KLF1 protein are associated with leukemia. We have made the unexpected findings that higher KLF1 levels are correlated with cells containing abnormal chromosomes, and that high KLF1 expression is not limited to acute myeloid leukemia (AML) associated with erythroid/megakaryoblastic differentiation. Expression of KLF1 is associated with poor survival. Further analyses reveal that KLF1 directly regulates a number of genes that play a role in chromosomal integrity. Together these results suggest that monitoring KLF1 levels may provide a new marker for risk stratification and prognosis in patients with AML.

CD123 expression levels in 846 acute leukemia patients based on standardized immunophenotyping.

BackgroundWhile it is known that CD123 is normally strongly expressed on plasmacytoid dendritic cells and completely absent on nucleated red blood cells, detailed information regarding CD123 expression in acute leukemia is scarce and, if available, hard to compare due to different methodologies.MethodsCD123 expression was evaluated using standardized EuroFlow immunophenotyping in 139 pediatric AML, 316 adult AML, 193 pediatric BCP‐ALL, 69 adult BCP‐ALL, 101 pediatric T‐ALL, and 28 adult T‐ALL patients. Paired diagnosis‐relapse samples were available for 57 AML and 19 BCP‐ALL patients. Leukemic stem cell (LSC) data was available for 32 pediatric AML patients. CD123 expression was evaluated based on mean fluorescence intensity, median fluorescence intensity, and percentage CD123 positive cells.ResultsEuroFlow panels were stable over time and between laboratories. CD123 was expressed in the majority of AML and BCP‐ALL patients, but absent in most T‐ALL patients. Within AML, CD123 expression was lower in erythroid/megakaryocytic leukemia, higher in NPM1 mutated and FLT3‐ITD mutated leukemia, and comparable between LSC and leukemic blasts. Within BCP‐ALL, CD123 expression was higher in patients with (high) hyperdiploid karyotypes and the BCR‐ABL fusion gene. Interestingly, CD123 expression was increased in BCP‐ALL relapses while highly variable in AML relapses (compared to CD123 expression at diagnosis).ConclusionsAuthors evaluated CD123 expression in a large cohort of acute leukemia patients, based on standardized and reproducible methodology. Our results may facilitate stratification of patients most likely to respond to CD123 targeted therapies and serve as reference for CD123 expression (in health and disease). © 2018 The Authors. Cytometry Part B: Clinical Cytometry published by Wiley Periodicals, Inc. on behalf of International Clinical Cytometry Society.

Long Non Coding RNA RP11-69I8.3 Expression in Acute Leukemia and Its Cinical Significance

To investigate the expression of long non coding RNA RP11-69I8.3 in acute leukemia and its clinical significance. lncRNA RP11-69I8.3 expression was detected by RT-PCR in bone marrow samples from 17 healthy controls, 32 newly diagnosed AML patients and 32 newly diagnosed ALL patients, and 25 ALL patients of complete remission after chemotherapy. Meanwhile, the clinical data were collected and the relation of lncRNA RP11-6918.3 expression with the clinical characteristics was analyzed. Compared with the control group, there was no significant difference in the expression of lncRNA RP11-69I8.3 in AML group(P>0.05). lncRNA RP11-69I8.3 lowly expressed in untreated ALL group(P=0.001). Compared with the de novo ALL group, lncRNA RP11-69I8.3 was highly expressed in complete remission ALL group (P<0.013). In 32 de novo ALL patients,the expression of lncRNA RP11-69I8.3 in children was significantly lower than that in adult(P=0.017). There was no correlation of the expression of lncRNA RP11-69I8.3 with the sex, WBC count, HB level, Plt count, LDH level, T or B type, ratio of bone marrow blast cell, BCR/ABL and WT1 fusion gene expression, chromosome karyotype, extramedullary infiltration, whether complete remission after one chemotherapy, whether relapse. In 26 B-ALL patients, there was no correlation between lncRNA RP11-69I8.3 and the immunophenotype. The expression of lncRNA RP11-69I8.3 in the untreated AML is not significantly different from the control group. lncRNA RP11-69I8.3 is low expressed in ALL group, highly expressed in ALL group with complete remission. In untreated ALL, the expression of lncRNA RP11-69I8.3 in children is significantly lower than that in adult. In B-ALL patients, the lncRNA RP11-69I8.3 is not relevant with the immunophenotype.

Aberrant Expression of CD Markers in Cases with Acute Leukemia in Sohag University Hospital

Introduction: Acute leukemias are a group of malignancies with clinical, morphologic, immunologic, and molecular patterns and display patterns of surface antigen expression (CD antigens). Precursor cells from different blast cells in acute leukemia express different subdivisions of surface molecules many of which are now defined as cluster of differentiation (CD) antigens. Every leukemia type has specific set of CD markers, what constitute nowadays current classification of hematopoietic malignancies and the basis of diagnosis. The expression of CD markers on leukocytes can be determined by flowcytometry. Immunophenotyping improves both accuracy and reproducibility of acute leukemia classification. Flow cytometry is a technique used to analyze multiple phenotypic and functional parameters simultaneously within a single cell or a population of cells. Aim of the work: Assess the prevalence of aberrant expression of CD markers in cases with acute leukemia in Sohag University Hospitals. Patients and Methods: This study was carried out in the Clinical Pathology Department, faculty of medicine, Sohag university hospital on fifty (50) newly diagnosed acute leukemia patients who were subjected to bone marrow aspiration, their ages ranged between 1.5 to 71 years, 29 (58%) of them were males and 21 (42%) were females with a male to female ratio of 1.4:1, during the period from November 2015 to October 2016. Results: B-cell acute lymphoblastic leukemia positive for the following CD markers CD10, CD19, TdT, HLA-DR and expressing CD33 and case of AML (M4-M5) expressing CD7 lymphoid marker. Conclusion: Aberrant expression of CD markers is seen in several cases of acute leukemia. The frequency of aberrant antigen expression in acute leukemia was comparable with most published international data. The presence of aberrancy helps to identify a neoplastic process.

TSC gene expression in the newly diagnosed Egyptian acute leukemia patients

TSC (tuberous sclerosis) complex is the major negative regulator of mTOR which activates cell cycle progression leading to uncontrolled growth. Acute leukemias are very heterogeneous as a group of hematological malignancies; they arise as a result of pled up genetic alterations. To study TSC gene expression in acute leukemia patients. Sixty-two Egyptian de no novo adult acute leukemia patients were assessed using SYBR green quantitative PCR as well as 22 controls. Correlation of TSC gene expression with response rate, other prognostic factors, and RFS was assessed. TSC1/TSC2 showed higher gene expression in acute leukemias compared to controls. TSC1 was significantly higher in T-ALL while TSC2 was significantly higher in B-ALL. Expression did not show significant correlation to known prognostic factors. TSC1/TSC2 overexpression might be implicated in the process of leukemogenesis.

Abstract 3724: PDL1 protein expression and tumor mutation burden in hematologic malignancies: correlation with Hodgkin and high grade lymphoma

Abstract Background: The success of anti PD–1 therapy in Hodgkin lymphoma has led to clinical trials in other types of lymphomas. However, there is limited data on PD–L1 expression in acute leukemias. In this study, we analyzed PD–L1 protein expression and tumor mutational burden in various hematologic malignancies including leukemias, lymphomas and myelomas. Methods: In the IHC cohort, formalin fixed paraffin embedded sections from 92 hematologic malignancies including acute myeloid and lymphoblastic leukemia (AML, ALL), Hodgkin lymphoma (HL), diffuse large B-cell lymphoma (DLBCL), low-grade non-Hodgkin lymphoma (LGNHL) and myeloma were immunostained using the FDA approved PD-L1 IHC 22C3 pharmDx assay [monoclonal mouse anti-PD–L1 antibody (DAKO clone 22C3)]. Any perceptible partial or complete membrane staining in all viable tumor cells was scored as follows: &amp;lt;1%-negative, 1-49%-low level and &amp;gt;50%-high level PD-L1 expression. In the second cohort of 2064 cases, comprehensive genomic profiling (CGP) was performed using a hybrid–capture, adaptor ligation assay to a mean depth of &amp;gt;672X. Tumor mutation burden (TMB) was calculated from a minimum of 1.11MB of sequenced DNA as previously described and reported as mutations/MB. High PD–L1 expression was noted in 100% of HL. DLBCL showed significantly higher PD–L1 positivity compared to LGNHL (p=0.01). No correlation for PD–L1 expression was noted between AML and ALL (p = 0.2). On CGP analysis of the second cohort, TMB was significantly higher in DLBCL as compared to LGNHL (p&amp;lt;0.0001). Conclusion: The high PD-L1 expression in both HL and DLBCL and high TMB in DLBCL may be linked to enhanced responsiveness to check point inhibitor therapy in these cancers. PD-L1 expression and TMB are relatively infrequent and at low levels in acute leukemias. Additionally, novel anti PD–1/PD–L1 therapeutic strategies are worthy of consideration for both advanced stage refractory/relapsed acute myeloid and lymphoblastic leukemias. Results: PD-L1 expression and TMB are tabulated below.PD-L1 IHCTMB (mutations/MB)Tumor typenLow PositiveHigh PositiveTotal Positive (%)n&amp;gt;=10.0&amp;gt;=20.0AML21505/21 (24%)50%0%ALL3212012/32 (38%)10%0%HL1001010/10 (100%)368%8%DLBCL10448/10 (80%)25344%15%LGNHL10202/10 (20%)930%0%Myeloma9202/9 (22%)NANANA Citation Format: Lina Abdul Karim, Peng Wang, Jose de Guzman, Brandi Higgins, Joeffrey Chahine, Christine Sheehan, Bhaskar Kallakury, Jeffrey S. Ross. PDL1 protein expression and tumor mutation burden in hematologic malignancies: correlation with Hodgkin and high grade lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3724. doi:10.1158/1538-7445.AM2017-3724

Evaluation of CD71 Expression in Acute Leukemia in Egyptian Patients

Background: CD71 or transferrin receptor is an integral membrane protein that mediates cellular iron uptake. It has been identified as a proliferation marker being expressed on many solid tumours as well as hematological neoplasms. Hence, CD 71 expression was assessed as a flow cytometric marker for leukemia and lymphoproliferative neoplasms. However, only few studies aimed to address its diagnostic and prognostic implications as well as its relation to clinical and laboratory markers. So, our study aimed at evaluation of the significance of CD71 (transferrin receptor 1, TfR-1) as a flow cytometric marker for the diagnosis of acute leukemia (AL). Methods: Seventy two patients diagnosed as acute leukemia; fifty six acute myeloid leukemia (AML) and sixteen Precursor B acute lymphoblastic leukemia (pre B ALL) were enrolled in the study and assessed for CD71 expression on blast cells by flow cytometry. Results: CD71expression was found to be significantly higher in acute myeloid leukemias than precursor B lymphoblastic leukemia (p:0.000) while median of MFI of CD71 was significantly higher in B lymphoblastic leukemia (p:0.016) than acute myeloid leukemia with the most remarkable expression was on poorly differentiated AML FAB subtypes. Conclusion: CD71 may be useful for the differential diagnosis of precursor B-ALL from AML in addition it could be useful in the evaluation of differentiation stage in case of AML.

Deregulation of the HOXA9/MEIS1 axis in acute leukemia.

HOXA9 is a homeodomain transcription factor that plays an essential role in normal hematopoiesis and acute leukemia, in which its overexpression is strongly correlated with poor prognosis. The present review highlights recent advances in the understanding of genetic alterations leading to deregulation of HOXA9 and the downstream mechanisms of HOXA9-mediated transformation. A variety of genetic alterations including MLL translocations, NUP98-fusions, NPM1 mutations, CDX deregulation, and MOZ-fusions lead to high-level HOXA9 expression in acute leukemias. The mechanisms resulting in HOXA9 overexpression are beginning to be defined and represent attractive therapeutic targets. Small molecules targeting MLL-fusion protein complex members, such as DOT1L and menin, have shown promising results in animal models, and a DOT1L inhibitor is currently being tested in clinical trials. Essential HOXA9 cofactors and collaborators are also being identified, including transcription factors PU.1 and C/EBPα, which are required for HOXA9-driven leukemia. HOXA9 targets including IGF1, CDX4, INK4A/INK4B/ARF, mir-21, and mir-196b and many others provide another avenue for potential drug development. HOXA9 deregulation underlies a large subset of aggressive acute leukemias. Understanding the mechanisms regulating the expression and activity of HOXA9, along with its critical downstream targets, shows promise for the development of more selective and effective leukemia therapies.

Survivin and cyclin E2 genes expression in a cohort of Egyptian acute leukemia patients: Clinical importance and future prospects.

Abnormalities in the control of apoptosis play an important role in leukemogenesis. Survivin is a member of inhibitor of apoptosis proteins family, it prevents apoptosis by blocking caspase activity and play a role in cell proliferation. While, cyclin E2 is one of the cyclins proteins family that controls progression of cell cycle by activation of cyclin dependant-kinase. Was to assess survivin and cyclin E2 genes expression in acute leukemia (AL) patients, and to define their role in the susceptibility of AL, and their correlation with the clinical presentation, laboratory findings, as well as treatment outcome. This study included 60 de novo AL patients and 40 control subjects to study the expression of survivin and cyclin E2 genes using RT-PCR. Survivin and cyclin E2 genes expression was significantly higher in leukemic patients compared with control subjects (P< 0.001), both genes separately were associated with increased risk of leukemia development and treatment failure (P< 0.01). Moreover, when combining the 2 genes expression, a significant elevation of the risk of leukemia and treatment failure was found (P < 0.01). Survivin and cyclin E2 genes expression may have clinical relevance and can be considered as molecular risk factors for AL. Also they may be useful as predictive markers for treatment outcome in leukemic patients.

NRP-1/CD304 expression in acute leukemia: a potential marker for minimal residual disease detection in acute leukemia

Background Neuropilin-1 (NRP-1, BDCA-4, or CD304) is a nontyrosine kinase coreceptor for semaphorins and vascular endothelial growth factor, involved in neural development and tumor angiogenesis. Objective The aim of this study was to evaluate NRP-1/CD304 expression in acute leukemia to be used as a potential marker for minimal residual disease (MRD) detection using flow cytometry. Materials and methods This study was conducted on 30 adults with newly diagnosed acute leukemia admitted to the Hematology Unit, Internal Medicine Department, Main Alexandria University Hospitals and Alexandria Research Institute within the period from February 2014 to December 2014, and 10 patients diagnosed with hypersplenism were also included as a control group. The following investigations were carried out for all patients: complete blood picture, bone marrow examination, and immunophenotyping using flow cytometry. Results This study showed that NRP-1/CD304 expression was statistically higher in B-lineage acute lymphoblastic leukemia (ALL) than in the acute myeloid leukemia and the control group (P = 0.002). There was a positive correlation between NRP-1/CD304 percentage expression and blast cell percentage in the bone marrow (P = 0.039). Follow-up of the patients on day 28 of induction chemotherapy revealed that NRP-1/CD304 expression was statistically higher in those who did not achieve complete remission than those who did (P = 0.035). Moreover, we observed that leukemic patients with extramedullary infiltration had statistically higher NRP-1/CD304 expression than those who did not have extramedullary infiltration (P = 0.023). All patients who achieved complete remission on day 28 of induction chemotherapy had negative MRD ( Conclusion It was observed that NRP-1/CD304 was expressed in almost all B-lineage ALL patients in variable degrees. It might be a useful marker in MRD detection of B-lineage ALL patients.

Transmembrane TNF-α preferentially expressed by leukemia stem cells and blasts is a potent target for antibody therapy

AbstractTo design an effective antibody therapy to improve clinical outcomes in leukemia, the identification of novel cell surface antigens is needed. Herein, we demonstrate a role for transmembrane tumor necrosis factor-α (tmTNF-α) in leukemia. To characterize tmTNF-α expression in acute leukemia (AL), normal hematopoietic cells, and nonhematopoietic tissues, we used a monoclonal antibody, termed C1, which specifically recognizes the tmTNF-α domain. We found that tmTNF-α was preferentially expressed by AL and leukemia stem cells (LSCs). More abundant expression correlated with poor risk stratification, extramedullary infiltration, and adverse clinical parameters. Moreover, knockdown of tmTNF-α+ expression rendered leukemia cells more sensitive to chemotherapy in vitro and delayed regeneration of leukemia in NOD-SCID mice. Targeting tmTNF-α by C1 resulted in leukemia cell killing via antibody-dependent cell-mediated and complement-dependent cytotoxicity in vitro and inhibited leukemia cell growth in vivo while simultaneously sparing normal hematopoietic cells. Notably, C1 administration impaired the regeneration of leukemia in secondary serial transplantation into NOD-SCID mice. In conclusion, tmTNF-α has a favorable AL- and LSC-associated expression profile and is important for the survival and proliferation of these cells. C1-mediated targeting shows potent anti-LSC activity, indicating that tmTNF-α represents a novel target antigen in AL.

Expression of the immunoglobulin superfamily cell membrane adhesion molecule Cd146 in acute leukemia.

The expression of the immunoglobulin superfamily cell membrane adhesion molecule CD146 has been reported on several normal and pathological cell types in human. The aim of this study was to investigate CD146 expression in acute leukemia using a multiparametric cytofluorimetric approach. Cytofluorimetric and cytogenetic studies were performed on peripheral blood and bone marrow samples from 162 patients with acute myeloid leukemia (AML, n = 121) and acute lymphoblastic leukemia (ALL, n = 41). ALL patients were subdivided in B-ALL (n = 38) and T-ALL (n = 3). Adult (n = 18) and pediatric (n = 20) B-ALL were considered as a whole group. Four out of 121 (3.3%) AML cases, 14/38 (36.8%) B-ALL, and 2/3 (66.6%) T-ALL expressed CD146 on 12-98% of blasts (p < 0.001). CD146 expression was not observed in 10 healthy controls. Among B-ALL CD146-positive cases, 78.6% were associated with a "common"/BII-ALL and 21.4% with a pre-B/BIII-ALL immunophenotype while pro-B/BI-ALL and mature-B/BIV-ALL cases were CD146-negative. Statistical analysis showed CD146 expression strongly associated with Ph+ positivity in B-ALL with the highest percentage of CD146-positive blasts in all Ph-positive B-ALL cases (84 ± 22% Ph-positive B-ALL SD vs. 40 ± 24% SD in Ph-negative B-ALL; p < 0,001). In our series, CD146 was expressed in all cases of Ph-positive B-ALL and in the vast majority of T-ALL, whereas it was rarely expressed by AML blasts. We suggest that CD146 may be considered as an additional marker for acute lymphoblastic leukemia diagnosis and monitoring of minimal residual disease in those cases which are CD146-positive at diagnosis. © 2015 International Clinical Cytometry Society.

Expression of costimulatory molecule B7-H3 and its prognostic implications in human acute leukemia

ObjectivesThis study focused on the expression pattern and clinical significance of B7-H3 expression in human acute leukemia.MethodsWe systematically analyzed 134 patients with acute myeloid leukemia (101 cases) and acute lymphocytic leukemia (33 cases) by flow cytometry.ResultsThe frequency of B7-H3+ cases was 44.8% in total. The B7-H3 expression rate differed from 0% to 74.8% in individual cases. The correlation between B7-H3 expression and traditional prognostic factors, such as age and gender, the white blood cell count was not confirmed. However, B7-H3 had a significant higher expression in CD34+ cases and high risk karyotypes.ConclusionsOwing to the expression of B7-H3 being statistically relevant in predicting disease progression and a shorter life survival, our results demonstrated that B7-H3 expression in acute leukemia predicts an unfavorable outcome.