scholarly journals Two Cases of Pediatric Acute Lymphoblastic Leukemia with t(5;14): a Challenging and Unique Entity

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4870-4870
Author(s):  
Renee-Pier Fortin-Boudreault ◽  
Elaine W. Leung ◽  
Mylene Bassal

Background: Pre-B acute lymphoblastic leukemia (B-ALL) with the t(5;14) translocation occurs in less than 1% of B-ALL diagnoses. This translocation links the IGH on chromosome 14 with IL-3, which results in hypereosinophilia. Interestingly, circulating blasts or cytopenias usually don't accompany the eosinophilia. Patients often present with symptoms related to the eosinophilia, which can be quite morbid, and can delay the diagnosis of ALL. Few pediatric patients with this association have been described in the literature. The presentation and outcome can be quite variable, although it is thought that the prognosis in those patients is worse than standard ALL. Objectives: To review the laboratory and clinical features of pediatric ALL with t(5;14). Methods: Cases of pediatric patients with ALL and t(5;14) diagnosed at the Children's Hospital of Eastern Ontario between 1995 and 2003 were reviewed. Results: We present two 11 year old children, a female and a male, who were diagnosed with B-ALL with t(5;14). The first one presented with a persisting low-grade fever and weight loss as well as asymptomatic lung infiltrates on the chest xray. The second patient presented with chest pain, fever, abdominal pain, as well as a petechial rash and splinter hemorrhages. His EKG showed ST depression, his troponins were elevated and an echocardiogram showed heart dysfunction. He went on and developed behavior changes and cerebral microinfarcts. Common to their presentation was the presence of hyperoesinophilia and absence of circulating blasts. Both had aggressive disease with persistent positive minimal residual disease (MRD) after consolidation and reinduction, which sent them to stem cell transplant. Conclusion: ALL with t(5;14) is a rare entity that usually presents with hypereosinophilia. While eosinophilia can be asymptomatic, it can also be the cause of important morbidity. Diagnosis can be delayed because of the absence of blasts in the peripheral blood and lack of severe cytopenia. Finally, due to its rarity, there is very little information available on how this cytogenic abnormality impacts prognosis, which seems to be worse than ALL without this translocation. Disclosures No relevant conflicts of interest to declare.

2019 ◽  
Vol 3 (13) ◽  
pp. 1926-1929 ◽  
Author(s):  
Amy K. Keating ◽  
Nathan Gossai ◽  
Christine L. Phillips ◽  
Kelly Maloney ◽  
Kristen Campbell ◽  
...  

Key Points Children treated with blinatumomab for B-ALL with MRD had few side effects and proceeded to hematopoietic cell transplant without delay. Blinatumomab given prior to transplant reduces MRD and results in favorable leukemia-free survival, toxicity, and overall survival.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 5269-5269
Author(s):  
Paola Bonaccorso ◽  
Manuela La Rosa ◽  
Nellina Andriano ◽  
Valeria Iachelli ◽  
Emanuela Cannata ◽  
...  

Abstract Background. Acute lymphoblastic leukemia (ALL) is the most common malignancy of childhood and a major cause of childhood cancer-related mortality. Although the cure rate now approaches 90%, certain pediatric ALL subgroups present subsequent relapse. For this reason, analyses of cell signaling pathways will help to identify new markers and/or targets for tailored therapy. PI3K/AKT/mTOR activation is frequently found in both B-ALL and T-ALL. Protein kinase Ck2 (CSNK2) activity in pediatric ALL was increased and its inhibition restored PTEN phosphatase activity with subsequent inactivation of AKT. Moreover, Ck2 may serve the activity of oncogenes such as BCR-ABL and c-MYC, control the activation of other critical signaling cascades (JAK-STAT), and sustain multiple cellular stress-elicited pathway such as the proteotoxic stress, unfolded protein and DNA-damage responses. Ck2 has also been shown to have an essential role in tuning signals derived from the stromal tumor microenvironment (Piazza F et al, Oncogene2016). Material and Methods. We analyzed cDNA collected from 46 patients with B-ALL [19 High Risk (HR) for Minimal Residual Disease (MRD) and 27 NON-HR] and 25 with T-ALL (8 HR and 17 NON-HR), respectively, diagnosed in our Center from 2000 to 2012. The latter subgroup was screened fro PTEN-Exon7 mutations and TXL3 rearrangements. We evaluated the gene expression of Ck2 and c-Myc genes using RQ-PCR with Sybr-Green and a relative quantification method (ΔΔCt method), comparing gene's expression from patients with samples from 6 healty donors (HDs). In order to demonstrate the correlation between genetic alteration and signaling transduction, specifically in HR patients , we analyzed some phosphoproteins by Phospho-flow approach. We profiled 5 proteins (STAT3, STAT5, CREB, PTEN and pS6) in 4 T-ALL cases (3 with PTEN-Exon 7 mutation). Results. We observed a significant difference of Ck2 expression in T-ALL NON-HR patients vs HDs (Mean Ck2 Fold-Changes 3.494 vs 1.17, p=0.0315) and in T-ALL HR patients (6.384 vs 1.17, p=0.0219) vs HDs (Fig 1A and B). Comparing NON-HR vs HR cases, we found a statistically significant difference (p<0.0001) (Fig 1C). c-Myc mean expression was very similar between the two T-ALL subgroups. Moreover, among T-ALL cases, we identified 5 patients with PTEN-Exon7 mutations and 6 with TLX3 rearrangements. We observed that cases with PTEN-Exon7 mutation showed lower c-Myc expression than cases with PTEN-Exon7 wild-type (mean c-Myc 8.550 vs 1.920) whereas patients with TLX3 rearrangements showed higher c-Myc expression than TLX3 negative (mean c-Myc 18.260 vs 5.502) (p<0.005) (Fig 2A and B). We did not observe any correlation between these rearrangements and Ck2 expression. We also performed Ck2 and c-Myc expression analysis in B-ALL (NON-HR and HR) subgroups. We surprisingly observed a Ck2 overexpression in both NON-HR and HR B-ALLs compared to HDs. On the other side, we did not observed significant difference about c-Myc expression in cases with B-ALL vs HDs; whilst we observed an overexpression of c-Myc in HR vs NON-HR patients with B-ALL (mean 7.075 vs 2.095, respectively)(p<0.0004). Phospho-Flow analysis, in 3 cases with PTEN-Exon7 mutation (1 Ck2+/normal Myc, 1 normal Ck2/normal Myc, 1 Ck2-/normal Myc) showed PTEN null, very lower pS6 basal level and higher CREB basal level than in case with PTEN-Exon7 wild-type. Moreover, we observed that the latter patient, presented with a TLX3 rearrangements (Ck2+/Myc+) with higher c-Myc expression, showed higher STAT3 basal state level confirming that STAT3 induces the expression of c-Myc. Conclusions. Based on our preliminary findings, Ck2 could be considered as a marker and /or a potential candidate for targeted therapy, specifically in HR-ALL, as confirmed by the use of CK2 inhibitor (CX-4945) in ongoing clinical trials. c-Myc overexpression confirmed its association with HR features. The potential role as markers of both genes needs to be demonstrated in a larger population study. Combined application of genomic and phosphoproteomic strategies will lead us to better profile diagnostic samples of HR-ALL, addressing future tailored treatments. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 808-808 ◽  
Author(s):  
Jonathan Bond ◽  
Tony Marchand ◽  
Aurore Touzart ◽  
Agata Cieslak ◽  
Amélie Trinquand ◽  
...  

Abstract Introduction: Gene expression studies have consistently identified a HOXA positive (HOXAPos) subgroup of T-cell acute lymphoblastic leukemia (T-ALL) (Ferrando et al, Cancer Cell 2002, Soulier et al, Blood 2005, Homminga et al, Cancer Cell 2011). It is however unclear if HOXAPos T-ALL constitutes a distinct and homogeneous clinical entity, and the biological consequences of HOXA over-expression have not been systematically examined. Methods: We identified and characterized the biological characteristics and clinical outcome of 55 HOXAPos cases among a cohort of 209 adult T-ALL patients who were uniformly treated as part of the Group for Research on Adult Acute Lymphoblastic Leukemia (GRAALL)-2003 and -2005 studies. Results: HOXAPos patients had higher rates of an early thymic precursor (ETP)-like immunophenotype (38% v 13.9%, p = 0.0008), early bone marrow chemoresistance (59.3% v 40.8%, p = 0.026) and positive minimal residual disease (MRD, 51.5% v 23.5%, p = 0.01) than the HOXANeg group. These differences were due to a particularly high frequency of chemoresistant ETP-ALL among HOXAPos cases harboring leukemic fusion proteins that trans-activate the HOXA locus (e.g. PICALM-MLLT10, SET-NUP214). Strikingly, the presence of an ETP-like immunophenotype conferred marked differences in outcome within the HOXAPos group (5 year event-free survival (EFS) 25% for HOXAPos ETP v 52.2% for HOXAPos non-ETP, p = 0.02), which were mirrored by corresponding increases in cumulative incidence of relapse (CIR, 57.1% v 25%, p = 0.01, Figure 1). In contrast, these survival differences were not seen in the HOXANeg patients, where ETP and non-ETP cases had similar 5 year EFS (54.9% v 50%, p = 0.73) and CIR (34.5% v 41.2%, p = 0.57). Multivariate analysis revealed that early bone marrow chemosensitivity was the clinico-biological covariate that had the strongest prognostic interaction with HOXA status. HOXA positivity conferred significant decreases in both the EFS and CIR of chemoresistant patients (p = 0.053 and 0.039 respectively), that was independent of white blood cell count (WCC), stem cell transplant (SCT), ETP phenotype, EGIL classification, and our recently reported risk classifier that integrates the prognostic effects of mutations of NOTCH1, FBXW7, RAS and PTEN (Trinquand et al, J Clin Oncol 2013). There were corresponding marked survival differences within the HOXAPos cohort between chemoresistant and chemosensitive cases. These disparities were not seen in the HOXANeg group, indicating that the prognostic value of chemosensitivity in adult T-ALL is specific to HOXAPos patients. Discussion: Our data show that clinico-biological phenotype is intimately linked to the underlying mechanism of HOXA locus deregulation, and we identify HOXA overexpression as a novel prognostic variable in ETP-ALL. Multivariate analysis suggests that this poor outcome is strongly related to intrinsic treatment resistance, and that this effect is exclusive to the HOXAPos cohort. Patients in the GRAALL-2003 and -2005 studies received enhanced induction and/ or salvage therapy in the event of poor early treatment response. Our results suggest that pediatric regimen-based intensification provides significant survival benefits for HOXANeg chemoresistant cases. In contrast, these modifications are inadequate for therapeutic rescue of the majority of HOXAPos chemoresistant ETP-ALL. The dramatically inferior prognosis of this group mandates consideration for alternative treatments in future clinical trials. Figure 1. Figure 1. Disclosures No relevant conflicts of interest to declare.


Author(s):  
Franco Locatelli ◽  
Gerhard Zugmaier ◽  
Noemi Mergen ◽  
Peter Bader ◽  
Sima Jeha ◽  
...  

The safety and efficacy of blinatumomab, a CD3/CD19-directed bispecific T-cell engager molecule, for treatment of pediatric relapsed/refractory B-cell precursor acute lymphoblastic leukemia (R/R B-ALL) were examined in an open-label, single-arm, expanded access study (RIALTO). Children (&gt;28 days, &lt;18 years) with CD19+ R/R B-ALL received up to five cycles of blinatumomab by continuous infusion (cycle: 4 weeks on/2 weeks off). The primary endpoint was incidence of adverse events. Secondary endpoints included complete response (CR) and measurable residual disease (MRD) response within the first two cycles, relapse-free survival (RFS), overall survival (OS) and allogeneic hematopoietic stem cell transplant (alloHSCT) after treatment. At final data cutoff (1/10/20), 110 patients were enrolled (median age, 8.5 years; 88% ≥5% blasts at baseline). Blinatumomab treatment resulted in a low incidence of grade 3-4 cytokine release syndrome (n=2 [1.8%]) and neurologic events (n=4 [3.6%]). No blinatumomab-related fatal adverse events were reported. The probability of response was not affected by the presence of cytogenetic/molecular abnormalities. Median OS was 14.6 months (95%CI: 11.0─not estimable) and was significantly greater for MRD responders versus MRD non-responders (not estimable vs 9.3; HR 0.18, 95%CI: 0.08─0.39). One-year OS probability was higher for patients who received alloHSCT versus without alloHSCT post-blinatumomab (87% versus 29%). Median RFS for MRD responders (n=57) was 8.0 months (95%CI:3.4─10.1) versus 2.8 months (95%CI: 0.3─9.2) for MRD non-responders (n=10). Of patients achieving CR after 2 cycles, 73.5% (95%CI: 61.4%-83.5%) proceeded to alloHSCT. These findings support the use of blinatumomab as a safe and efficacious treatment for pediatric R/R B-ALL. (ClinicalTrials.gov identifier NCT02187354)


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 409-409
Author(s):  
Petra Breithaupt ◽  
Barbara Meissner ◽  
Martin Zimmermann ◽  
Anja Möricke ◽  
André Schrauder ◽  
...  

Abstract Abstract 409 Alteration of the IKZF1 gene – encoding the transcription factor IKAROS, a key player in lymphoid development and tumor suppression – has been reported to be associated with a poor outcome in pediatric precursor B-cell ALL, especially in cases positive for the BCR-ABL1 fusion gene. In order to assess the prognostic value of IKZF1 deletions in a representative cohort of pediatric ALL patients treated on the German ALL-BFM 2000 study protocol, we screened 409 patients by applying a multiplex ligation-dependent probe amplification (MLPA) assay covering all eight IKZF1 exons (P335-A3 ALL-IKZF1 probemix; MRC-Holland, Amsterdam, The Netherlands). In ALL-BFM 2000, risk group stratification (standard, SR; intermediate, MR; high, HR) was based on minimal residual disease (MRD) analysis at two different time points (TP) and required two MRD targets with sensitivities of ≤10−4 (Flohr et al. Leukemia 2008). SR patients were MRD-negative on treatment days 33 (TP1) and 78 (TP2). HR patients had residual disease (≥10−3) at TP2. MRD MR patients had positive MRD detection at either one and or both time points but at a level of <10−3 at TP2. Although MRD-based stratification criteria were introduced in ALL-BFM 2000, established high-risk parameters were also retained: patients with prednisone poor-response or ≥5% leukemic blasts in the bone marrow on day 33 or positivity for a t(9;22) or t(4;11) or their molecular equivalents (BCR/ABL1 or MLL/AF4 fusion RNA) were stratified into the high-risk group independent of their MRD results. First results on MRD and outcome were published earlier (Conter et al. Blood 2010). Out of the 409 patients analyzed in our study, 46 (11%) displayed a deletion in at least one of the eight IKZF1 exons. Forty-three out of the 46 cases showed heterozygous deletions, while 3 patients displayed homozygous loss of IKZF1 exons. MLPA results of 11 patients were validated with results derived from copy number/LOH analyses using Affymetrix SNP 6.0 arrays. IKZF1 deletion was significantly more common in precursor B compared to T cell ALL (13% vs. 4%, P = 0.03) and less frequent in TEL/AML1-positive ALL (3% vs. 13%, P = 0.004). Out of 11 BCR/ABL1-positive samples, only two were characterized by an IKZF1 deletion. Forty-four patients with IKZF1-deleted ALL had results of MRD analyses available for both informative time points (day 33 after induction and day 78 after consolidation). Despite a trend towards increasing incidence of IKZF1 deletion in patients with slow response, the distribution of IKZF1-deleted ALL patients over the risk groups was not significantly different from non-deleted ALL (SR: 40.9 vs. 41.9; MR: 45.5 vs. 52.3; HR: 13.6 vs. 5.7%; P = 0.153). Regarding treatment outcome, patients with an IKZF1 deletion had a significantly lower 5-year event-free survival (EFS) compared to non-deleted patients (0.78±0.06 vs. 0.86±0.02; P = 0.015). This result was due to a higher cumulative incidence of relapses in IKZF1-deleted patients (0.16±0.05 vs. 0.10±0.02; P = 0.031). In multivariate Cox regression analyses including known prognostic variables (gender, immunophenotype, WBC count at diagnosis, TEL/AML1 status, risk group criteria of ALL-BFM 2000), IKZF1 deletion conferred a risk of 2.16 (95% confidence interval 1.14 – 4.10; P = 0.018) for an event when compared to non-deleted patients. We conclude that IKZF1 deletion is an independent predictor of treatment outcome for patients enrolled on the ALL-BFM 2000 protocol and represents a candidate marker to be integrated in future algorithms for early risk stratification in pediatric ALL. Disclosures: No relevant conflicts of interest to declare.


2019 ◽  
Vol 3 (4) ◽  
pp. 670-680 ◽  
Author(s):  
Moshe Yeshurun ◽  
Daniel Weisdorf ◽  
Jacob M. Rowe ◽  
Martin S. Tallman ◽  
Mei-Jie Zhang ◽  
...  

Abstract Allogeneic hematopoietic cell transplant is a potential curative therapy for acute lymphoblastic leukemia (ALL). Delineating the graft-versus-leukemia (GVL) effect as a function of graft-versus-host disease (GVHD) offers the potential to improve survival. We examined 5215 transplant recipients with ALL reported to the Center for International Blood and Marrow Transplant Research registry. Overall survival (OS) was compared according to the presence and severity of GVHD and evaluated in 3 cohorts: 2593 adults in first or second complete remission (CR1/CR2), 1619 pediatric patients in CR1/CR2, and 1003 patients with advanced (CR ≥3 or active disease) ALL. For patients in CR1/CR2, development of acute GVHD (aGVHD) or chronic GVHD (cGVHD) was associated with lower risk of relapse than no GVHD (hazard ratio [HR], 0.49-0.69). Patients with advanced ALL developing grades III and IV aGVHD or cGVHD were also at lower risk of relapse (HRs varied from 0.52 to 0.67). Importantly, adult and children in CR1/CR2 with grades I and II aGVHD without cGVHD experienced the best OS compared with no GVHD (reduction of mortality with HR, 0.83-0.76). Increased nonrelapse mortality accompanied grades III and IV aGVHD (HRs varied from 2.69 to 3.91) in all 3 cohorts and abrogated any protection from relapse, resulting in inferior OS. Patients with advanced ALL had better OS (reduction in mortality; HR, 0.69-0.73) when they developed cGVHD with or without grades I and II aGVHD. In conclusion, GVHD was associated with an increased GVL effect in ALL. GVL exerted a net beneficial effect on OS only if associated with low-grade aGVHD in CR1/CR2 or with cGVHD in advanced ALL.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 4934-4934
Author(s):  
Mei Huang ◽  
Lubing Gu ◽  
Muxiang Zhou

Abstract Abstract 4934 Triptolide, a nature product derived from the Chinese plant Tripterygium wilfordii, is reported to exhibit antitumor effects in a broad range of cancers. Recent studies indicate that the antitumor activity of triptolide is associated with its biological action to inhibit expression of many oncoproteins and anti-apoptotic or survival factors that were expressed in the cancer cells. Herein, we demonstrate that triptolide induces apoptosis in a subgroup of acute lymphoblastic leukemia (ALL) cells that overexpress MDM2 oncoprotein by inhibiting the MDM2 expression. In pediatric ALL, overexpression of MDM2 by leukemic cells is typically associated with a wild-type (wt) p53 phenotype and resistance to conventional chemotherapeutic drugs such as doxorubicin. In the present study, we evaluated the role of triptolide in regulating MDM2 and in inducing apoptosis, as compared to doxorubicin, using ALL lines and primary ALL samples. In contrast to doxorubicin, which induced p53 activation and a subsequent upregulation of MDM2, triptolide strongly induced persistent inhibition of MDM2 followed by a steady-state activation of p53, which resulted in potent apoptosis of the MDM2-overexpressing ALL cells tested, even if they were doxorubicin-resistant. We discovered that triptolide's inhibition of MDM2 in ALL cells occurred at the post-transcriptional level through inhibition of mRNA synthesis. Because p53 function is inhibited by MDM2 in chemoresistant/MDM2-overexpressing ALL cells, potent killing of these cells by triptolide suggests that this naturally-derived agent may be a novel therapeutic for refractory ALL. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2490-2490
Author(s):  
Abdusebur Jemal ◽  
Jeffrey W Tyner ◽  
Mathew Thayer ◽  
Markus Muschen ◽  
Brian J. Druker ◽  
...  

Abstract Abstract 2490 Background: Pediatric Acute Lymphoblastic Leukemia (ALL) remains the most common pediatric malignancy. Despite advances in treatment and outcomes, there continue to be subsets of patients that are refractory to standard intensive chemotherapy and hematopoietic stem cell transplant. Therefore, novel gene targets for therapy are needed to further advance treatment for this disease. Survivin, a member of the chromosome passenger complex and inhibitor of apoptosis has been shown to be over-expressed in malignant cells and in relapsed ALL. Therefore, survivin may be a potential target for therapy in pediatric ALL. The selective survivin suppressant, YM155 (Astellas) has been shown to inhibit survivin expression and activate cell death in multiple cell lines. Early phase I studies show promise in both tolerability and possible efficacy in B-cell malignancies. Therefore, this drug may have the potential of improving treatment for pediatric B-cell precursor ALL. Design/methods: Pediatric lymphoblastic cell lines, fresh primary lymphoblast cells from newly diagnosed patients with ALL and xenografted patient samples were used in this study. Cells were incubated in the presence of YM155 at doses ranging from 1nM to 10μM. Viability was measured using a standard methane-thiosulfonate viability assay. Activation of apoptosis was identified using the Guava nexin Annexin V binding assay for cell lines. Results: Treatment of ALL cell lines, primary patient samples and xenograft samples show a dose-dependent sensitivity to YM155 by both activation of apoptosis and by cell viability. IC50 doses for the majority of the samples are in the low nanomolar range (Table). Interestingly, there is some variability amongst patient samples suggesting possible variable responses in vivo. Ectopic expression of survivin in cell lines treated with YM155 rescues the effect of the drug. Further, t(9;22) positive ALL samples, including primary patient, xenograft, and dasatinib resistant samples remain significantly sensitive to YM155. For dasatinib sensitive Ph+ALL samples, combination therapy suggest an additive effect by isobologram analysis. Conclusion: Pediatric ALL samples remain sensitive to treatment with YM155 in cell lines, primary patient and xenografted samples. The results of these experiments will be used as a foundation to develop a comprehensive understanding of the mechanisms of survivin dependence in pediatric ALL. Future studies will also be designed to develop YM155 as an additional therapy for pediatric acute lymphoblastic leukemia. Disclosures: Druker: Cylene:; MolecularMD:; Novartis:; Bristol-Myers-Squibb:.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1419-1419
Author(s):  
Kenji Tokunaga ◽  
Shunichiro Yamaguchi ◽  
Eisaku Iwanaga ◽  
Tomoko Nanri ◽  
Taizo Shimomura ◽  
...  

Abstract Abstract 1419 Aims: Molecular pathogenesis of acute lymphoblastic leukemia (ALL) has largely been verified in pediatric patients and the identification of genetic alterations have contributed to stratifying therapeutic applications. In adult patients with ALL, cytogenetic and genetic abnormalities have not sufficiently been elucidated and therapeutic improvement has been hindered. CREB binding protein (CREBBP) is a transcriptional coactivator that interacts with a diverse range of transcription factors and regulates transcription by histone acetylation in hematopoiesis. Mutations of the CREBBP gene are recently found in approximately 2–4% of pediatric patients with ALL. Especially in relapsed cases, the mutations prevail (18–63%) and are possible markers for prediction of relapse in pediatric ALL. In adult patients with ALL, the clinical significance of CREBBP mutations remains to be determined. Here we examined adult ALL patients in an attempt to determine the incidence, clinical characteristics and prognostic impact of the CREBBP mutations. Methods: We investigated 71 adult patients with newly diagnosed ALL treated with JALSG protocols between 1986 and 2010. Age ranged from 15 to 86 years, with a median of 54 years. CREBBP mutations are dominantly identified in histone acetyltransferase (HAT) domain. HAT domain in the CREBBP gene was amplified with RT-PCR using RNA isolated from the peripheral blood or bone marrow mononuclear cells at diagnosis and was subjected to direct sequencing. We compared clinical profiles between patients with and without CREBBPHAT domain mutations. This study was approved by the Institutional Review Boards and informed consent was obtained from each patient according to guidelines based on the revised Declaration of Helsinki. Results: CREBBP HAT domain mutations were detected in 8 of 71 (11.3%) patients: one nonsense mutation, five insertion mutations with frameshifts, and five missense mutations. Two patients harbored biallelic mutations. The mutations at diagnosis in adult patients were seen more frequently than those in pediatric patients ever reported. Such mutations were not completely identical to those detected in pediatric ALL, but were seen in the region within the HAT domain, indicating that such mutations are loss-of-function mutations. The mutations were found in both B-cell (6/53: 11.3%) and T-cell (1/9: 11.1%) ALL, and distributed in patients harboring IKZF1 alterations (3/31: 9.7%) or the BCR-ABL fusion gene (2/19: 10.5%). There were no statistical difference in age, sex, leukocyte, platelet counts and complete remission rate between patients with and without the CREBBP HAT domain mutations. Patients with the mutations had a trend with worse cumulative incidence of relapse (P=0.4637), relapse-free survival (P=0.4195) and OS (P=0.2349) compared to patients lacking the mutations, but statistical significance was not detected in this small cohort. Conclusions: CREBBP HAT domain mutations at diagnosis in adult ALL are found more frequently than in pediatric ALL. This may be one of the mechanisms that adult ALL has been associated with poor OS compared with pediatric ALL. In this study, CREBBP HAT domain mutations were observed in various subtypes of ALL: both B-cell and T-cell ALL, and both Philadelphia chromosome positive and negative ALL. In pediatric ALL, CREBBP mutations were frequently seen in relapsed patients but not in previously untreated patients. These observations suggest that CREBBP mutations play an important role in an additional late event(s) leading to the development and progression of ALL. Our study implies the possibility that mutations of the CREBBP gene are associated with the pathogenesis and prognostic marker of adult ALL and represent specific epigenetic modifiers in adult ALL, serving as potential therapeutic targets. Disclosures: No relevant conflicts of interest to declare.


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