Expression of Angiopoietins and Their Receptor Tie2 in the Bone Marrow of Patients with Acute Myeloid Leukemia.

Abstract Angiopoietin-1 (Ang-1) and its natural antagonist Angiopoietin-2 (Ang-2), both ligands for the receptor tyrosine kinase Tie2, are known to play an essential role in normal and pathological angiogenesis. However, the importance of angiopoietin signaling in the pathophysiology of hematologic neoplasias such as acute myeloid leukemia (AML) remains to be elucidated. We investigated the expression of Ang-1, Ang-2 and Tie2 by immunohistochemical analyses in bone marrow biopsies of 64 adult patients with newly diagnosed AML and correlated angiogenic factor expression with clinicopathological variables and long-term survival. Expression of Ang-2 was significantly increased in the bone marrow of AML patients (median [interquartile ranges]: 4.7 [3.3 – 5.7] AU [arbitrary units]) as compared with 16 control patients (1.5 [1.5 – 1.8] AU; P < 0.0001). In contrast, Ang-1 expression levels in AML patients did not differ from those found in controls. Thus, we observed a reversal of the Ang-1 and Ang-2 expression balance in the neoplastic bone marrow (Ang-2:Ang-1 ratio: 1.73) as compared with normal bone marrow (0.51; P < 0.0001). Furthermore, the angiopoietin receptor Tie2 was significantly overexpressed in leukemic blasts (3.8 [2.8 – 4.9] AU vs. 1.8 [1.6 – 2.3] AU; P < 0.0001). Patients expressing high levels of Ang-2 showed significantly longer overall survival (OS) than those with low Ang-2 levels (52.7 vs. 14.7 months; P = 0.039). The impact of Ang-2 expression on OS was especially evident in AML patients simultaneously expressing low levels of Ang-1 (P = 0.0298). Multivariate Cox regression analysis revealed karyotype and Ang-2 expression as independent prognostic factors for OS (hazard ratio [CI]: 3.06 [1.39 – 6.70] and 0.31 [0.14 – 0.69], respectively; P < 0.01). In conclusion, these data provide evidence that the alteration of angiopoietin balance in favor of Ang-2 may play a critical role in the pathophysiology of AML. Furthermore, high pre-therapeutic bone marrow Ang-2 levels indicate a favorable prognosis in polychemotherapy treated AML by a yet unknown mechanism.

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Pan-RAF Inhibition Shows Anti-Leukemic Activity in RAS-Mutant Acute Myeloid Leukemia Cells and Potentiates the Effect of Sorafenib in Cells with FLT3 Mutation

Cancers ◽

10.3390/cancers12123511 ◽

2020 ◽

Vol 12 (12) ◽

pp. 3511

Author(s):

Joseph D. Khoury ◽

Mehrnoosh Tashakori ◽

Hong Yang ◽

Sanam Loghavi ◽

Ying Wang ◽

...

Keyword(s):

Acute Myeloid Leukemia ◽

Cell Signaling ◽

Myeloid Leukemia ◽

Critical Role ◽

Cyclin B1 ◽

Leukemic Cells ◽

Phase Array ◽

Flt3 Mutations ◽

The Impact ◽

Acute Myeloid

RAF molecules play a critical role in cell signaling through their integral impact on the RAS/RAF/MEK/ERK signaling pathway, which is constitutively activated in a sizeable subset of acute myeloid leukemia (AML) patients. We evaluated the impact of pan-RAF inhibition using LY3009120 in AML cells harboring mutations upstream and downstream of RAF. LY3009120 had anti-proliferative and pro-apoptotic effects and suppressed pERK1/2 levels in leukemic cells with RAS and FLT3 mutations. Using reverse protein phase array analysis, we identified reductions in the expression/activation of cell signaling components downstream of RAF (activated p38) and cell cycle regulators (Wee1/cyclin B1, Cdc2/Cdk1, activated Rb, etc.). Notably, LY3009120 potentiated the effect of Ara-C on AML cells and overcame bone marrow mesenchymal stromal cell-mediated chemoresistance, with RAS-mutated cells showing a notable reduction in pAKT (Ser473). Furthermore, the combination of LY3009120 and sorafenib resulted in significantly higher levels of apoptosis in AML cells with heterozygous and hemizygous FLT3 mutations. In conclusion, pan-RAF inhibition in AML using LY3009120 results in anti-leukemic activity, and combination with Ara-C or sorafenib potentiates its effect.

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Improvement in outcome for children receiving allogeneic bone marrow transplantation in first remission of acute myeloid leukemia: a report from the Groupe d'Etude des Greffes de Moelle Osseuse.

Journal of Clinical Oncology ◽

10.1200/jco.1992.10.12.1865 ◽

1992 ◽

Vol 10 (12) ◽

pp. 1865-1869 ◽

Cited By ~ 15

Author(s):

G Michel ◽

E Gluckman ◽

D Blaise ◽

H Esperou-Bourdeau ◽

J P Vernant ◽

...

Keyword(s):

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Bone Marrow Transplantation ◽

Marrow Transplantation ◽

Myeloid Leukemia ◽

Acute Gvhd ◽

Short Time Interval ◽

Allogeneic Bone ◽

Term Survival ◽

Acute Myeloid

PURPOSE We retrospectively analyzed the outcome of children with acute myeloid leukemia (AML) in first complete remission (CR) who received HLA-identical bone marrow transplantation (BMT) in 13 French transplant centers. PATIENTS AND METHODS Seventy-four children were treated from June 1979 through December 1990. The conditioning regimen included total-body irradiation (TBI) in 54 cases and busulfan in 20. Prophylaxis of graft-versus-host disease (GVHD) consisted of cyclosporine (CycloA) plus methotrexate (MTX) for 38 patients, MTX for 17, CycloA for 18, and T depletion without other prophylaxis for one. The mean value of the interval from diagnosis to transplantation was 167 days. RESULTS Sixteen patients died of transplant-related complications, 12 relapsed, and 46 are alive in continuous remission with a median follow-up of 46 months. We examined results obtained over three successive periods: 1979 to 1982 (n = 14 children), 1983 to 1986 (n = 29), and 1987 to 1990 (n = 31). Probabilities of event-free survival (EFS) were 43%, 48%, and 82% for the three successive periods, respectively (P < .02). This improvement in EFS was linked to a decreased risk of transplant-related mortality: 36%, 36%, and 3%, respectively (P < .01). Other factors associated with a better EFS in the univariate analysis were a short time interval from diagnosis to transplant (< 120 days), the absence of significant (grade > or = 2) acute GVHD, and the absence of chronic GVHD. In the multivariate analysis, two factors had a favorable impact on long-term survival: the year of transplantation (years 1987 to 1990 v others) and the absence of acute GVHD. CONCLUSION The outcome for children receiving allogeneic BMT in first CR of AML has improved in France during recent years.

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SETDB1 mediated histone H3 lysine 9 methylation suppresses MLL-fusion target expression and leukemic transformation

Haematologica ◽

10.3324/haematol.2019.223883 ◽

2019 ◽

Vol 105 (9) ◽

pp. 2273-2285 ◽

Cited By ~ 4

Author(s):

James Ropa ◽

Nirmalya Saha ◽

Hsiangyu Hu ◽

Luke F. Peterson ◽

Moshe Talpaz ◽

...

Keyword(s):

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Myeloid Leukemia ◽

Target Genes ◽

Critical Role ◽

High Expression ◽

Leukemia Cells ◽

Biological Impact ◽

Hematopoietic Stem ◽

Acute Myeloid

Epigenetic regulators play a critical role in normal and malignant hematopoiesis. Deregulation, including epigenetic deregulation, of the HOXA gene cluster drives transformation of about 50% of acute myeloid leukemia. We recently showed that the Histone 3 Lysine 9 methyltransferase SETDB1 negatively regulates the expression of the pro-leukemic genes Hoxa9 and its cofactor Meis1 through deposition of promoter H3K9 trimethylation in MLL-AF9 leukemia cells. Here, we investigated the biological impact of altered SETDB1 expression and changes in H3K9 methylation on acute myeloid leukemia. We demonstrate that SETDB1 expression is correlated to disease status and overall survival in acute myeloid leukemia patients. We recapitulated these findings in mice, where high expression of SETDB1 delayed MLL-AF9 mediated disease progression by promoting differentiation of leukemia cells. We also explored the biological impact of treating normal and malignant hematopoietic cells with an H3K9 methyltransferase inhibitor, UNC0638. While myeloid leukemia cells demonstrate cytotoxicity to UNC0638 treatment, normal bone marrow cells exhibit an expansion of cKit+ hematopoietic stem and progenitor cells. Consistent with these data, we show that bone marrow treated with UNC0638 is more amenable to transformation by MLL-AF9. Next generation sequencing of leukemia cells shows that high expression of SETDB1 induces repressive changes to the promoter epigenome and downregulation of genes linked with acute myeloid leukemia, including Dock1 and the MLL-AF9 target genes Hoxa9, Six1, and others. These data reveal novel targets of SETDB1 in leukemia that point to a role for SETDB1 in negatively regulating pro-leukemic target genes and suppressing acute myeloid leukemia.

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Immunoistochemical expression of PD-1 and PD-L1 in bone marrow biopsies of patients with acute myeloid leukemia

Hematology Reports ◽

10.4081/hr.2020.8211 ◽

2020 ◽

Vol 12 (1) ◽

Author(s):

Francesco Romano ◽

Antonino Giulio Giannone ◽

Sergio Siragusa ◽

Rossana Porcasi ◽

Ada Maria Florena

Keyword(s):

Bone Marrow ◽

Immune Response ◽

Acute Myeloid Leukemia ◽

Myeloid Leukemia ◽

Immune Escape ◽

Medical Community ◽

Immune Checkpoints ◽

Bone Marrow Biopsies ◽

Underlying Mechanisms ◽

Acute Myeloid

tumor immunotherapy is a rapidly evolving field. The discovery of the ability of neoplasms to evade the immune response has shifted the attention of the medical community to the underlying mechanisms of the immune response to tumors, highlighting the importance of so-called immune check points, including CTLA4, TIM-3 and PD-1. an immune escape mechanism is the activation of the immune checkpoint pathway that contributes to the creation of an immunosuppressive microenvironment and therefore to tumor proliferation.although immune checkpoints have been extensively investigated in solid tumors, the same is not true for hematologic neoplasms, particularly for myeloid malignancies. our study is based on the evaluation of the activation of the PD-1 and PD-L1 pathway in the context of the bone marrow tumor microenvironment of patients with acute myeloid leukemia. To do so we evaluated 34 bone marrow biopsies of patients with acute myeloid leukemia comparing them to 10 controls using immunohistochemical methods.

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Characterization of Extramedullary Acute Myeloid Leukemia – Results of the AML96 Trial

Blood ◽

10.1182/blood.v116.21.2154.2154 ◽

2010 ◽

Vol 116 (21) ◽

pp. 2154-2154

Author(s):

Friedrich Stölzel ◽

Christoph Röllig ◽

Michael Kramer ◽

Brigitte Mohr ◽

Uta Oelschlägel ◽

...

Keyword(s):

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Induction Chemotherapy ◽

Myeloid Leukemia ◽

The Body ◽

Hematopoietic Stem ◽

Npm1 Mutation ◽

Mutation Status ◽

The Impact ◽

Acute Myeloid

Abstract Abstract 2154 Background: Myeloid Sarcoma (MS) is defined as an extramedullary mass composed of myeloid blasts occurring at an anatomical site other than the bone marrow. Furthermore, the term extramedullary manifestation (EM) is applied if it accompanies overt acute myeloid leukemia (AML) and represents non-effacing tissue infiltration. EM is reported to correspond often to the skin but can affect almost every site of the body. The prognosis of MS or EM has been discussed controversially in the past. EM at diagnosis of AML is generally thought to be a rare event. However, data defining the prevalence of EM at diagnosis of AML and its prognostic value are missing. The aim of this analysis was to provide data for estimating the prevalence of EM at diagnosis of AML and to determine its relevance by including clinical and laboratory data from patients being treated in the prospective AML96 trial of the Study Alliance Leukemia (SAL) study group. Patients and Methods: A total of 326 patients with AML (age 17 – 83 years) and EM were treated within the AML96 trial with a median follow up of 8.8 years (95% CI, 8.4 to 9.3 years). All patients received double induction chemotherapy. Consolidation therapy contained high-dose cytosine arabinoside and for patients ≤ 60 years of age the option of autologous or allogeneic hematopoietic stem cell transplantation (HSCT). Logistic regression analyses were used to identify prognostic variables for CR rates. The method of Kaplan-Meier was used to estimate OS and EFS. Confidence interval (CI) estimation for the survival curves was based on the cumulative hazard function using the Greenwood's formula for the SE estimation. Survival distributions were compared using the log rank test. Results: 17% of the AML patients entered into the AML96 trial were diagnosed with EM. In 313 of the 326 patients (96%) EM was evident at diagnosis. The majority of patients with EM were diagnosed with de novo AML (84%, n=273), whereas gingival infiltration (51%, n=166) displayed the main EM of AML with CNS involvement being less common (4%, n=14). The majority of patients had a cytogenetic intermediate risk profile (71%, n=221) with a total of 172 patients (56%) harboring a normal karyotype. Patients with EM had a statistically significant lower median CD34-positivity of bone marrow blasts, higher percentage of FAB subtypes M4 and M5, higher WBC counts and LDH at diagnosis and higher percentage of NPM1 mutations compared to those patients without EM (all p<.001). When comparing achievement of CR between patients with EM to patients without EM, no statistical difference between these two groups was observed. Analysis according to the NPM1/FLT3-ITD mutation status revealed highest 5-year-OS (37%, 95% CI: .24 - .508) and 5-year-EFS (36%, 95% CI: .224 - .448) in the NPM1-mut/FLT3-wt group and lowest 5-year-OS (12%, 95% CI: 0 - .261) and 5-year-EFS (4%, 95% CI: 0 - .124) in the NPM1-wt/FLT3-ITD group, p=.007 and p=.001, respectively. Of the 49 relapsed patients with EM who had a NPM1-mutation at diagnosis 48 deceased despite of intensified relapse therapies. Conclusions: This analysis represents the largest study so far investigating the impact of EM AML. Patients with EM AML have distinct differences from AML patients without EM regarding their clinical and molecular characteristics at diagnosis. However these differences do not translate into differences in response to induction chemotherapy. Compared to patients without EM, survival analysis revealed differences according to the NPM1/FLT3-ITD mutation status which is also described for patients without EM AML. However, the prognosis for patients with EM who harbor a mutated NPM1 the prognosis at relapse seems to be dismal. Disclosures: No relevant conflicts of interest to declare.

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Inhibition of HDAC8 Reactivates p53 and Abrogates Leukemia Stem Cell Activity in CBFβ-SMMHC Associated Acute Myeloid Leukemia

Blood ◽

10.1182/blood.v124.21.363.363 ◽

2014 ◽

Vol 124 (21) ◽

pp. 363-363

Author(s):

Jing Qi ◽

Qi Cai ◽

Sandeep Singh ◽

Ling Li ◽

Hongjun Liu ◽

...

Keyword(s):

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Myeloid Leukemia ◽

Bone Marrow Cells ◽

Conflicts Of Interest ◽

Cell Activity ◽

Disease Free Survival ◽

Hematopoietic Stem ◽

The Impact ◽

Acute Myeloid

Abstract The inv(16)-created CBFβ-SMMHC fusion protein inhibits differentiation of hematopoietic stem and progenitor cells (HSPCs) and creates pre-leukemic populations predisposed to acute myeloid leukemia (AML) transformation. However, the molecular mechanism underlying the leukemogenic function of CBFβ-SMMHC has been elusive. Given the low TP53 mutation rate in AML, alternative mechanisms disrupting p53 function are expected. We showed thatCBFβ-SMMHC impairs p53 acetylation and p53 target gene activation through formation of an aberrant protein complex with p53 and HDAC8 (Blood, 120: A772; 122(21): 224). We now show that CBFβ-SMMHC binds to p53 and HDAC8 independently through distinct regions and that HDAC8 mediates the deacetylation of p53 associated with CBFβ-SMMHC. In addition, we generated mice carrying a floxed Hdac8 (Hdac8f) allele and crossed with Cbfb56M/+/Mx1-Cre (Kuo YH et al, Cancer Cell 2006). Deletion of Hdac8 signifiacntly (p<0.0001) reduced the incidence of AML and prolonged disease-free survival. Pharmacologic inhibition of HDAC8 activity with HDAC8-selective inhibitors (HDAC8i) reactivates p53 and selectively induces apoptosis of inv(16)+ AML CD34+ cells while sparing normal HSPCs. To test the effect of HDAC8i on LSC engraftment and leukemia-initiating capacity, we generated Cbfb56M/+/Mx1-Cre mice with a Cre-reporter line expressing tdTomato fluorescence protein following Cre-mediated recombination. AML cells (dTomato+/cKit+) treated with HDAC8i (22d) ex vivo showed reduced engraftment (p=0.025) and enhanced survival (p=0.025) in transplanted mice. To examine whether HDAC8i 22d treatment affects the engraftment capacity on surviving cells, we transplanted equal number (2 x 106) of AML cells treated with either 22d or vehicle in another cohort of mice (n=4). We show that HDAC8i 22d treatment reduced the engraftment of dTomato+/cKit+ AML cells and enhanced survival, suggesting that the engraftment capacity is altered in addition to reducing AML cell survival. We next performed preclinical studies to determine the efficacy of in vivo administration of HDAC8i 22d. AML transplanted mice were randomized into two groups, one group treated with vehicle and the other treated with HDAC8i 22d for 2 weeks. Flow cytometry analysis revealed significantly reduced frequency (p=0.0097) and number (p=0.0101) of dTomato+/cKit+ AML cells in the bone marrow and spleen of 22d treated mice compared to vehicle treated group. To further assess the impact on LSC activity, we transplanted bone marrow cells from these treated mice into secondary recipients and analyzed for AML engraftment. Significant reduction in the frequency (p<0.0001) and the number (p=0.0006) of dTomato+/cKit+ AML cells was observed in the bone marrow and spleen. Furthermore, HDAC8i 22d treated transplants showed no signs of leukemia while vehicle treated transplants are moribund with aggressive AML. These results indicate that HDAC8 inhibition by 22d treatment effectively eliminates engraftment and leukemia-initiating capacity of AML LSCs. In conclusion, our studies identify a novel post-translational p53-inactivating mechanism and demonstrate selective HDAC8 inhibition as a promising approach to target inv(16)+ AML LSCs. Disclosures No relevant conflicts of interest to declare.

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Increased angiogenesis in the bone marrow of patients with acute myeloid leukemia

Blood ◽

10.1182/blood.v95.8.2637.008k07_2637_2644 ◽

2000 ◽

Vol 95 (8) ◽

pp. 2637-2644 ◽

Cited By ~ 3

Author(s):

Teresa Padró ◽

Sandra Ruiz ◽

Ralf Bieker ◽

Horst Bürger ◽

Martin Steins ◽

...

Keyword(s):

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Complete Remission ◽

Induction Chemotherapy ◽

Microvessel Density ◽

Myeloid Leukemia ◽

Remission Induction ◽

Bone Marrow Biopsies ◽

Acute Myeloid

The importance of angiogenesis for the progressive growth and viability of solid tumors is well established. In contrast, only few data are available for hematologic neoplasms. To investigate the role of angiogenesis in acute myeloid leukemia (AML), bone marrow biopsies from 62 adults with newly diagnosed, untreated AML (day 0) were evaluated. Further studies were done after the completion of remission induction chemotherapy (day 16 of induction chemotherapy, n = 21; complete remission, n = 20). Microvessels were scored in at least 3 areas (×500 field, 0.126 mm2) of the highest microvessel density in representative sections of each bone marrow specimen using immunohistochemistry for von Willebrand factor and thrombomodulin. Microvessel counts were significantly higher in patients with AML (n = 62) compared with control patients (n = 22): median (interquartile range) 24.0 (21.0-27.8)/×500 field vs 11.2 (10.0-12.0)/×500 field, respectively (P < .001). On day 16 of induction chemotherapy, microvessel density was reduced by 60% (44-66) (P < .001) in hypoplastic marrows without residual blasts, in contrast to only 17% (0-37) reduction in hypoplastic marrows with ≥ 5% residual blasts (P < .001 for the difference between both groups). Bone marrow biopsies taken at the time of complete remission displayed a microvessel density in the same range as the controls. In conclusion, there is evidence of increased microvessel density in the bone marrow of patients with AML, which supports the hypothesis of an important role of angiogenesis in AML. Furthermore, these findings suggest that antiangiogenic therapy might constitute a novel strategy for the treatment of AML.

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PROGNOSTIC VALUE OF BRAIN AND ACUTE LEUKEMIA CYTOPLASMIC GENE EXPRESSION IN EGYPTIAN CHILDREN WITH ACUTE MYELOID LEUKEMIA

Mediterranean Journal of Hematology and Infectious Diseases ◽

10.4084/mjhid.2015.033 ◽

2015 ◽

Vol 7 ◽

pp. e2015033 ◽

Cited By ~ 2

Author(s):

Adel Abd elhaleim Hagag

Keyword(s):

Gene Expression ◽

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Complete Remission ◽

Acute Leukemia ◽

Myeloid Leukemia ◽

Egyptian Children ◽

Significant Difference ◽

The Impact ◽

Acute Myeloid

Abstract Background: Acute myeloid leukemia (AML) accounts for 25%-35% of the acute leukemia in children. BAALC (Brain and Acute Leukemia, Cytoplasmic gene) is a recently identified gene on chromosome 8q22.3 that has prognostic significance in AML. The aim of this work was to study the impact of BAALC gene expression on prognosis of AML in Egyptian children. Patients and methods: This study was conducted on 40 patients of newly diagnosed AML who were subjected to the following: Full history taking, clinical examination, laboratory investigations including: complete blood count, LDH, bone marrow aspiration, cytochemistry and immunophenotyping, assessment of BAALC Gene by real time PCR in bone marrow aspirate mononuclear cells before the start of chemotherapy. Results: BAALC gene expression showed positive expression in 24 cases (60%) and negative expression in 16 cases (40%). Patients who showed positive BAALC gene expression included 10 patients achieved complete remission, 8 patients died and 6 relapsed patients, while patients who showed negative expression include 12 patients achieved complete remission, 1 relapsed patient and 3 patients died. There was significant association between BAALC gene expression and FAB classification of patients of AML patientsas positive BAALC expression is predominantly seen in FAB subtypes M1 and M2 compared with negative BAALC gene expression that was found more in M3 and M4 (8 cases with M1, 12 cases with M2, 1 case with M3 and 3 cases with M4 in positive BAALC expression versus 2 cases with M1, 3 cases with M2, 4 cases with M3 and 7 cases with M4 in BAALC gene negative expression group with significant difference regarding FAB subtypes). As regard age, sex, splenomegaly, lymphadenopathy, pallor, purpura, platelets count, WBCs count, and percentage of blast cells in BM, the present study showed no significant association with BAALC. Conclusion: BAALC expression is an important prognostic factor in AML patients and its incorporation into novel risk-adapted therapeutic strategies will improve the currently disappointing cure rate of this group of patients.

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Increased angiogenesis in the bone marrow of patients with acute myeloid leukemia

Blood ◽

10.1182/blood.v95.8.2637 ◽

2000 ◽

Vol 95 (8) ◽

pp. 2637-2644 ◽

Cited By ~ 317

Author(s):

Teresa Padró ◽

Sandra Ruiz ◽

Ralf Bieker ◽

Horst Bürger ◽

Martin Steins ◽

...

Keyword(s):

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Complete Remission ◽

Induction Chemotherapy ◽

Microvessel Density ◽

Myeloid Leukemia ◽

Remission Induction ◽

Bone Marrow Biopsies ◽

Acute Myeloid

Abstract The importance of angiogenesis for the progressive growth and viability of solid tumors is well established. In contrast, only few data are available for hematologic neoplasms. To investigate the role of angiogenesis in acute myeloid leukemia (AML), bone marrow biopsies from 62 adults with newly diagnosed, untreated AML (day 0) were evaluated. Further studies were done after the completion of remission induction chemotherapy (day 16 of induction chemotherapy, n = 21; complete remission, n = 20). Microvessels were scored in at least 3 areas (×500 field, 0.126 mm2) of the highest microvessel density in representative sections of each bone marrow specimen using immunohistochemistry for von Willebrand factor and thrombomodulin. Microvessel counts were significantly higher in patients with AML (n = 62) compared with control patients (n = 22): median (interquartile range) 24.0 (21.0-27.8)/×500 field vs 11.2 (10.0-12.0)/×500 field, respectively (P < .001). On day 16 of induction chemotherapy, microvessel density was reduced by 60% (44-66) (P < .001) in hypoplastic marrows without residual blasts, in contrast to only 17% (0-37) reduction in hypoplastic marrows with ≥ 5% residual blasts (P < .001 for the difference between both groups). Bone marrow biopsies taken at the time of complete remission displayed a microvessel density in the same range as the controls. In conclusion, there is evidence of increased microvessel density in the bone marrow of patients with AML, which supports the hypothesis of an important role of angiogenesis in AML. Furthermore, these findings suggest that antiangiogenic therapy might constitute a novel strategy for the treatment of AML.

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Shorter Remission Telomere Length Predicts Delayed Neutrophil Recovery After Acute Myeloid Leukemia Therapy: A Report From the Children’s Oncology Group

Journal of Clinical Oncology ◽

10.1200/jco.2016.66.9622 ◽

2016 ◽

Vol 34 (31) ◽

pp. 3766-3772 ◽

Cited By ~ 12

Author(s):

Robert B. Gerbing ◽

Todd A. Alonzo ◽

Lillian Sung ◽

Alan S. Gamis ◽

Soheil Meshinchi ◽

...

Keyword(s):

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Telomere Length ◽

Myeloid Leukemia ◽

Protein Structures ◽

Telomere Maintenance ◽

Oncology Group ◽

Neutrophil Recovery ◽

The Impact ◽

Acute Myeloid

Purpose Suboptimal outcomes for children with acute myeloid leukemia (AML) necessitate maximally intensive therapy. Consequently, serious adverse events, such as prolonged periods of profound myelosuppression, contribute to AML treatment–related mortality. Telomeres, the repetitive DNA–protein structures at chromosome ends, influence cellular replicative capacity in that critically short telomeres can induce cell senescence or apoptosis. Our objective was to evaluate the impact of telomere length on duration of post-therapy neutropenia in a pediatric AML cohort. Patients and Methods Patients were diagnosed with de novo AML, enrolled in Children’s Oncology Group study AAML0531, and included those with (n = 53) and without (n = 62) significantly delayed neutrophil recovery after chemotherapy. We used quantitative polymerase chain reaction to measure telomere content (TC), a validated proxy for telomere length, from remission bone marrow samples obtained after the second induction chemotherapy course. Results Less TC was significantly associated with prolonged neutropenia after the fourth ( P < .001) and fifth chemotherapy courses ( P = .002). Cox regression adjusting for age at diagnosis confirmed that TC remained independently predictive of time to recovery of absolute neutrophil count for both the fourth and fifth courses ( P = .002 and .009, respectively). DNA from patients was analyzed for germline mutations in four telomere maintenance genes associated with telomere biology disorders. Sequence analysis revealed no enrichment of rare or novel variants in the delayed recovery group. Conclusion Our results suggest that TC at end of AML induction is associated with hematopoietic reconstitution capacity independently of age and may identify those at highest risk for markedly delayed bone marrow recovery after AML therapy.

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