Brain And Acute Leukemia, Cytoplasmic Gene Expression Research Articles

Prognostic significance of combined BAALC and MN1 gene expression level in acute myeloid leukemia with normal karyotype.

Acute myeloid leukemia with normal karyotype (AML-NK) is the largest group of AML patients with very heterogeneous disease outcome. In order to ensure more precise risk stratification new molecular markers have been introduced, like expression level for BAALC (Brain and Acute Leukemia, Cytoplasmic) and MN1 (Meningioma 1) genes. In this study, we investigated expression level of both genes in 111 adult AML-NK at diagnosis and examined their prognostic potential. BAALC and MN1 expression were detected in about one third of the patients, and positive correlation between these two genes was found. The BAALC+ /or MN1+ status was not associated with the presence of FLT3-ITD mutations, but exhibited strong correlation with NPM1wt status (P<.001). Therefore, among BAALC+ /or MN1+ patients the most frequent ones were FLT3-ITD- /NPM1- double negative patients with intermediate prognosis. When BAALC+ /or MN1+ patients were divided into BAALChigh /BAALClow (21/21) and MN1high /MN1low (21/22) groups, we detected that BAALChigh /or MN1high patients had a tendency toward lower complete remission rate. Also, survival analysis showed that BAALChigh /or MN1high patients had shorter disease-free survival and overall survival (OS). The most pronounced influence on prognosis was detected in FLT3-ITD- /NPM1- group of patients that are lacking reliable prognostic markers, where OS in BAALChigh /or MN1high was only 5months vs 25months in BAALClow /or MN1low . These findings indicate that BAALC and MN1 expression level could be used for more precise risk stratification of AML-NK patients and especially FLT3-ITD- /NPM1- patients, transforming this intermediate-risk group, into a group with an adverse prognosis.

Relation of BAALC and ERG Gene Expression with Overall Survival in Acute Myeloid Leukemia Cases

The objectives of this study were to evaluate the expression of brain and acute leukemia, cytoplasmic (BAALC) gene and erythroblast transformation-specific related gene (ERG) in de novo cases of acute myeloid leukemia (AML) and identify roles in disease progression and outcome. This study included 50 newly diagnosed AML patients, along with 10 apparently healthy normal controls. BAALC and ERG expression was detected in the bone marrow of both patients and controls using real-time RT-PCR. BAALC and ERG expression was detected in 52% of cases but not in any controls. There was a statistically significant correlation between BAALC and ERG gene expression and age (p- value=0.004 and 0.019, respectively). No statistical significance was noted for sex, lymphadenopathy, hepatomegaly, splenomegaly, other hematological findings, immunophenotyping and FAB sub-classification except for ERG gene and FAB (p-value=0.058). A statistical significant correlation was found between response to treatment with ERG expression (p-value=0.028) and age (p-value=0.014). A statistically significant variation in overall survival was evident with patient age, BM blast cells, FAB subgroups, BAALC and ERG expression (p-value= <0.001, 0.045, 0.041, <0.008 and 0.025 respectively). Our results suggest that BAALC and ERG genes are specific significant molecular markers in AML disease progression, response to treatment and survival.

Prognostic significance of the BAALC gene expression in adult patients with acute myeloid leukemia: A meta-analysis.

Numerous studies have investigated the prognostic role of brain and acute leukemia, cytoplasmic (BAALC) gene expression in adult patients with acute myeloid leukemia (AML); however, the results are inconclusive. A meta-analysis was conducted to provide a comprehensive evaluation of the prognostic role of BAALC gene expression in AML. Eligible studies were searched through PubMed, Embase, the Cochrane Library, the China National Knowledge Infrastructure and the China Biology Medicine Disc. Correlations between the BAALC gene expression and clinicopathological features and prognosis were analyzed. A total of 15 studies were examined. The pooled results suggest that high BAALC expression had an unfavorable outcome in AML. The combined hazard ratio (HR) for overall survival (OS) was 1.53 and the summary HR for the disease-free survival rate was 1.64. In addition, subgroup analyses considering cytogenetic and survival analysis were also conducted. High BAALC gene expression appeared to be an adverse prognostic indicator in patients with cytogenetically normal AML (HR for OS, 1.43) and in subgroups of survival analysis with multivariate analysis (HR for OS, 2.35). These results indicate that high BAALC gene expression served as an independent poor prognostic indicator in adult patients with AML.

Prognostic value of brain and acute leukemia cytoplasmic gene expression in egyptian children with acute myeloid leukemia.

BackgroundAcute myeloid leukemia (AML) accounts for 25%–35% of acute leukemia in children. BAALC gene (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 methodsThis study was conducted on 40 Egyptian children with newly diagnosed AML who were subjected to full history taking, clinical examination and laboratory investigations including: complete blood count, LDH, bone marrow aspiration, cytochemistry, immunophenotyping and assessment of BAALC Gene by real time PCR in bone marrow aspirate mononuclear cells before the start of chemotherapy.ResultsPositive BAALC gene expression was found in 24 cases (60%) and negative expression in 16 cases (40%). Positive BAALC gene expression group includes 14 males and 10 females with mean age at presentation of 8.35±2.63 while negative BAALC gene expression includes 10 males and 6 females with mean age at presentation of 7.74±3.23 with no statistically significant differences between patients with positive and negative BAALC gene expression regarding age, sex and clinical presentations at time of diagnosis including pallor, purpura, splenomegaly, hepatomegaly and lymphadenopathy and laboratory investigations including WBCs and platelets counts, hemoglobin and LDH levels, and peripheral blood and bone marrow blast cell counts. There was significant association between positive BAALC gene expression and M1 and M2 compared with negative BAALC gene expression which is significantly associated with M4. There were statistically significant differences in disease outcome between positive and negative BAALC gene expression groups with higher rate of relapse and death and lower rate of complete remission and disease free survival in positive BAALC gene expression group compared with negative BAALC gene expression group. (p = 0.017).Conclusion and RecommendationBAALC expression is an important bad prognostic factor in AML patients with normal karyotype and therefore we recommend its incorporation into novel risk-adapted therapeutic strategies to improve the currently disappointing cure rate of patients with AML.

Prognostic Implication of BAALC Gene Expression in Adult Acute Myeloid Leukemia

Recently various molecular markers and global gene expression profiling have been investigated to improve risk profile characterization of AML with normal cytogenetics. Our main objective is to investigate the prognostic impact of brain and acute leukemia, cytoplasmic (BAALC) expression in AML with normal karyotype. BAALC expression was analysed using quantitative real time (QRT) PCR. High expression was detected in 22 of 45 patients (48.9%) and its expression did not correlate with the clinical parameters of patients. High BAALC expressers had significantly lower incidence of CR (22.7% vs. 73.9%; p = 0.001), higher mortality rate (72.1% vs. 39.1%; p = 0.023), showed significantly shorter DFS (mean 4.5 vs. 13.21 months, p < 0.001), and inferior overall survival (7.02 vs. 15.02 months, p < 0.001). Multivariable analysis confirmed high BAALC expression as an independent risk factor for DFS and OS. BAALC expression is an important prognostic factor in AML patients with normal karyotype and its incorporation into novel risk-adapted therapeutic strategies will improve the currently disappointing cure rate of this group of patients.

Detection of an Unbalanced Ratio Between WT1 Isoforms in Acute Myeloid Leukemia and Its Correlation with Molecular Abnormalities.

AbstractAbstract 2500Wilms’ tumor gene 1 (WT1) is a tumor suppressor gene coding for a zinc finger transcriptional factor which was found overexpressed in acute myeloid leukemias (AML). In AML WT1 functions as an oncogene rather than a tumor suppressor. This may depend on the unbalanced expression of its different isoforms derived from alternative splicing in exon 5 (EX5+/−) or the presence of KTS in exon 9 ( KTS+/KTS-). In normal hematopoietic cells the physiological ratio between KTS+/KTS- isoforms is 1:1. KTS are inserted between the third and fourth zinc fingers thus influencing the DNA binding and therefore the transcriptional activity.The aim of the study was to investigate the possibility of an unbalanced ratio between the isoforms thus leading to the disruption of WT1 function. In addition we correlated KTS+ isoform with clinical and biological features. Methods: we analyzed KTS+/KTS- isoforms in 120 AML patients ( 102 BM samples, 18 PB), 63 chronic phase CML patients (48 BM and 15 PB). In addition we evaluated 5 samples of selected blast cells from AML patients. In a subset of 38 adult acute myeloid leukemia (AML) patients we measured all WT1 isoforms (A[EX5 -/KTS -], B[+/−], C[-/+] and D[+/+]. Quantitative PCR was used for the WT1 isoforms detection and measurement. Results:KTS+ isoform is significantly overexpressed with a ratio KTS+/KTS− 2:1 in both AML and CML patients and it is confirmed in blast cell samples. In the subgroup of patients analyzed for the expression pattern of all WT1 isoforms we detected a significant overexpression of isoform D (EX5+/KTS+) (median value 821) while the isoform A (EX5−/KTS−) is the less represented ( median value 303). In this subgroup the expression of KTS+ isoforms (B+D) is higher than KTS- ( A+C) with a median value of 642 compared to 421. The ratio of WT1 isoforms was not significantly different among FAB subgroups or according to cytogenetic risk, FLT3 (fms-like tyrosine kinase receptor-3) internal tandem duplication or exon 17 mutation, NPM (nucleophosmin) gene mutations and BAALC (brain and acute leukemia, cytoplasmic) gene expression. Conclusion:Although WT1 is overexpressed in AML and CML patients it lacks its typical tumor suppressor function. In this study we have demonstrated the overexpression of WT1 KTS+ isoforms. In addition we have previously demonstrated that KTS+ isoform does not have transcriptional activity since it is mainly localized within the cytoplasm. In conclusion, WT1 is overexpressed in AML but the unbalanced ratio between the isoforms may probably influence the transcriptional activity. Any possible correlation between the unbalanced ratio of WT1 isoforms and clinical outcome requires further prospective studies to be established. Disclosures:No relevant conflicts of interest to declare.

Elevated BAALC Gene Expression Lacks Clinical Significance in Pediatric AML- A Report From the Children's Oncology Group.

AbstractAbstract 2553▪▪This icon denotes a clinically relevant abstract Background:High expression of the brain and acute leukemia, cytoplasmic (BAALC) gene is associated with inferior outcomes in adult AML patients with normal cytogenetics. Studies regarding the significance of BAALC expression in pediatric AML are limited. We studied BAALC expression in a cohort of children with de novo AML to evaluate its clinical significance in pediatric AML, particularly in patients with standard-risk (SR) disease. Methods:BAALC mRNA expression was measured via qRT-PCR in diagnostic specimens obtained from 206 patients enrolled on COG AAML03P1. Expression levels were normalized against pooled normal blood controls (PNB). To evaluate the impact of BAALC expression values on clinical outcome, samples were dichotomized at the median expression level (14.9) into a BAALClow (N= 103, median expression 2.9; range 0.0089–14.897) and BAALChigh (N=103; median expression 65; range 15.064–369.53) subset. Baseline clinical features were compared for BAALClow vs. BAALChigh patients and categorical variables compared using the chi-square test and Fisher exact test when data were sparse. The Kaplan-Meier method was used to estimate OS, EFS and DFS for the 2 groups. Estimates of RR were obtained using methods that accounted for competing events. Similar methods were used for sub-analysis of n=99 SR patients. Results:Compared to expression in PNB, BAALC expression varied over 5 log fold (range 0.0089–369.53); the median BAALC expression was 14.98. There were no differences between BAALClow and BAALChigh patients with respect to disease presentation (WBC, BM blast%, Hb, platelet count) though patients with BAALChigh expression were older (median age 12.2 vs. 7.8; years; p=0.001). NPM1 mutations were more frequent in the BAALClow subset (12% vs 0%, p=0.002) however CEBPA and FLT3/ITD mutations were not associated with BAALC expression. Favorable cytogenetics were associated with BAALChigh expression [t(8;21): 1% vs. 23%, p=<0.001; inv (16) 5% vs. 26%;p=<0.001] whereas normal cytogenetics and 11q23abnormalities were more frequent in the BAALClow cohort [normal cytogenetics 32% vs 13%; p=0.002; 11q23: 33% vs. 6%; p=<0.001]. High-risk cytogenetic features were not associated with BAALC expression in limited analysis (n=6 patients). BAALC expression was also correlated with disease-risk, a classification derived from prognostic cytogenetic and molecular features. BAALChigh was more common in patients with low-risk disease (19% vs. 54%, p=<0.001) whereas BAALClow was more frequently seen in SR patients (69% vs 32% p=<0.001). There was no association between high-risk patients and BAALC expression in a limited number of samples analyzed (n=26). Induction response was independent of BAALC expression (77% vs. 82%, p=0.442) although minimal residual disease (MRD) at end of induction was marginally associated with high expression (20% vs. 35%, p=0.058). There were no differences in OS and EFS from study entry for BAALClow vs. BAALChigh patients (5 year OS: 64% vs. 63%, p=0.832; EFS 49% vs. 48%, p=0.868) Corresponding DFS and RR from CR were also comparable (DFS: 58% vs. 56%, p=0.608; RR 34% vs. 31%, p=0.735).We further evaluated the association of BAALC expression with outcome in patients with SR disease. SR BAALClow and SR BAALChigh patients had similar disease presentation (WBC, BM blast %, platelet count, Hb) and were similar in age. Abnormalities of 11q23 were associated with SR BAALClow expression (51% vs. 24%; p=0.006) but other SR cytogenetic abnormalities including normal cytogenetics were not. Rates of induction CR were similar for SR BAALClow versus SR BAALChigh patients (77% vs. 66%, p=0.225) as were rates of end induction MRD (21% vs. 37%, p=0.178). Importantly, there were no differences in OS and EFS from study entry for SR BAALClow vs. SR BAALChigh patients (5 year OS: 56% vs. 59%, p=0.464; EFS 42% vs. 37%, p=0.899). Corresponding DFS and RR from CR were also comparable (DFS: 56% vs. 47%, p=0.756; RR 36% vs. 41%, p=0.990). Conclusions:In this study, elevated BAALC expression was not associated with clinical outcome, within our total study cohort and in those patients with SR disease. This suggests that BAALC expression may lack independent prognostic significance within pediatric AML, despite its association with specific disease characteristics. Validation of our findings in a larger pediatric cohort, and in all disease-risk groups, is ongoing within COG protocol AAML0531. Disclosures:Franklin:Amgen: Employment.

ShRNA-Mediated BAALC knockdown affects proliferation and apoptosis in human acute myeloid leukemia cells

Brain and acute leukemia, cytoplasmic (BAALC) is a novel molecular marker indicating an inferior outcome in acute myeloid leukemia (AML) with normal cytogenetics. The biological function of BAALC is largely unknown. In this study, BAALC gene expression in an acute myeloid leukemia cell line KG1a was knocked down by a small hairpin RNA (shRNA). The expression of BAALC mRNA and protein in the knockdown cells was significantly inhibited. The proliferation and apoptosis status in the knockdown cells were investigated. The growth curves and FACS analysis demonstrated that BAALC gene knockdown resulted in decreased proliferation and enhanced apoptosis in KG1a cells. These results indicated that BAALC may act as an adverse prognostic factor through prompting proliferation and inhibiting apoptosis in leukemia cells.

In Acute Promyelocytic Leukemia (APL) Low BAALC Gene Expression Identifies a Group of Patients with Favorable Outcome in Overall Survival and Relapse Free Survival,

Abstract 3543 Introduction:Acute promyelocytic leukemia (APL) is characterized by the translocation t(15;17) which results in the PML-RARα fusion protein. ATRA based treatment regimens lead to long term survival in approximately 75% of cases. However, relapse occurs in about 15% of APL patients. Moreover, it is not yet known which underlying pathomechanisms drive relapse of the disease. In addition, to avoid over- or undertreatment of patients, respectively, risk stratification of patients according to biological or molecular criteria would most probably improve current treatment modalities. As opposed to other leukemias, in APL no molecular markers have been established for risk stratification as yet. The gene brain and acute leukemia, cytoplasmic (BAALC) has been shown to be of prognostic relevance in other leukemias such as T acute lymphoblastic leukemia (T-ALL) and acute myeloid leukemia (AML). Therefore, the aim of our study was to evaluate whether BAALC expression could be of prognostic value in APL.Materials and Methods: Bone marrow mononuclear cells were retrospectively evaluated in 86 APL patients after informed consent. 50 patients were female and 36 patients were male. Median age was 47 years (range: 19–82 years). All patients were diagnosed and treated in the German AML Cooperative Group (AMLCG) study. The treatment consisted of simultaneous ATRA and double induction (TAD/HAM) chemotherapy including high-dose ara-C, one cycle of consolidation chemotherapy (TAD) and 3 years monthly maintenance chemotherapy. BM cells were analyzed by multiplex reverse transcriptase quantitative real-time PCR (qRT-PCR) in triplicates on a LightCycler 480 (Roche, Mannheim, Germany). Glucose-6-phosphate-isomerase (GPI) served as a housekeeping gene for normalization. For quantification of relative expression values a modified delta-delta CT calculation model according to Pfaffl was used (Pfaffl MW, Nucleic Acids Res; 2001) after determination of PCR efficiencies. BAALC expression groups were defined as follows: BAALC expression lower than the 25th percentile (BAALClow) and higher than the 25th percentile (BAALC high). Time to complete remission, relapse free survival (RFS) and overall survival (OS) were calculated using the Kaplan-Meier method and a log-rank test was used to compare differences between the groups (p < 0.05). For statistical analysis the Statistical Analysis Software version 9.2 was used. Results:In univariate analysis low BAALC expression was significantly associated with a superior OS. Patients in the BAALClow group showed an OS at 10 years of 82% as compared to 60% in the BAALChigh group (p=0.025). Moreover, RFS in the BAALClow group was significantly higher at 10 years as compared to the BAALChigh group (86% vs. 59%; p=0.0087). Time to complete remission was not correlated to BAALC expression levels. Conclusion:Low BAALC expression identifies a group of APL patients with a highly superior outcome indicated by a better OS and RFS in these patients. However, these findings need to be validated in an independent prospective study and it should be investigated whether this marker is independent of the applied treatment regimen and other known relevant markers. However, since the translocation t(15;17) by itself is not able to induce leukemia BAALC might be an interesting target for further investigation. Disclosures:No relevant conflicts of interest to declare.

WT1 overexpression at diagnosis may predict favorable outcome in patients with de novo non-M3 acute myeloid leukemia

We reviewed the frequency and prognostic significance of FLT3 (fms-like tyrosine kinase receptor-3) and NPM (nucleophosmin) gene mutations and WT1 (Wilms’ tumor) and BAALC (brain and acute leukemia, cytoplasmic) gene expression in 100 consecutive patients with intermediate and poor cytogenetic risk de novo acute myeloid leukemia (AML) receiving conventional anthracycline–AraC based therapy. We observed a strict relationship between unfavorable karyotype and BAALC >1000 (p = 0.0001). Multivariate analysis of 81 patients with intermediate karyotype revealed that younger age (p = 0.00009), NPM gene mutation (p = 0.002), and WT1 >75th percentile (>2365) (p = 0.003) were independent, positive factors for complete remission (CR). WT1 expression above 2365 was correlated also to longer event-free survival (EFS) and overall survival (OS) in the same subset of patients (p = 0.003 and p = 0.02, respectively); the same finding occurred in younger patients with AML with intermediate karyotype (p = 0.008 and p = 0.01, respectively). In patients with intermediate karyotype, FLT3 internal tandem duplication (ITD) negatively affected EFS (EFS at 30 months: 30% vs. 6% in FLT3-ITD negative and FLT3 positive patients, respectively; p = 0.01) and OS (OS at 30 months: 38% vs. 20%, p = 0.03). The positive prognostic value of high WT1 expression does not have a clear explanation; it may be implicated either with WT1 anti-oncogenic function, or with the stimulating effect of WT1 oncogene on the leukemic cellular cycle, possibly associated with an enhanced response to chemotherapy.

Prognostic significance of the BAALC isoform pattern and CEBPA mutations in pediatric acute myeloid leukemia with normal karyotype: a study by the Japanese Childhood AML Cooperative Study Group

High BAALC (brain and acute leukemia, cytoplasmic) gene expression may indicate an adverse prognosis for adults who have acute myeloid leukemia (AML) and a normal karyotype, but its prognostic significance for pediatric AML cases is unclear. Whether different BAALC isoform patterns are of prognostic significance is also unclear. Newly diagnosed AML patients with normal karyotype who were treated by the Japanese Childhood AML Cooperative Treatment Protocol AML 99 were analyzed in terms of their BAALC expression levels (n = 29), BAALC isoforms (n = 29), and CEBPA mutations (n = 49). Eleven and 18 patients exhibited high and low BAALC expression, respectively, but these groups did not differ significantly in terms of overall survival (54.6 vs. 61.1%, P = 0.55) or event-free survival (61.4 vs. 50.0%, P = 0.82). Three of these 29 patients (10.3%) expressed the exon 1-5-6-8 BAALC isoform along with the expected 1-6-8 isoform and had adverse clinical outcomes. Novel CEBPA mutations were also identified in four of 49 patients (8.2%). All four patients have maintained complete remission for at least 5 years. Thus, 1-5-6-8 isoform expression may be associated with an adverse prognosis in pediatric AML with normal karyotype. CEBPA mutations may indicate a favorable prognosis.

Molecular Monitoring of ERG and BAALC as Minimal Residual Disease Markers in Patients with Acute Leukemia.

Although expression of the genes ERG (ETS-related gene) and BAALC (brain and acute leukemia, cytoplasmic) predicts outcome in acute leukemia, there is little information about their utility as markers of minimal residual disease (MRD). A real-time quantitative reverse transcriptase-polymerase chain reaction (RQ-PCR) was used to examine relative levels of ERG and BAALC gene expression in 11 patients with acute leukemia. Pretreatment and post-chemotherapy bone marrow (BM) samples were analyzed to quantify these transcripts. Peripheral blood (PB) samples were also obtained to evaluate the correlation of ERG and BAALC expression levels in BM and PB samples. Significant levels of ERG gene were expressed in all patients. In contrast with ERG, the levels of BAALC gene expression were significantly lower in some patients. Continuous monitoring of the ERG mRNA was performed and assessed a correlation between MRD levels and subsequent clinical courses. In patients with relative high expression of BAALC transcripts (>7x10exp-3/GAPDH), high levels of ERG gene expressions were consistently observed whether they were in remission status or not. In 2 patients with acute promyelocytic leukemia (APL), MRD was simultaneously monitored by RQ-PCR using primers for PML/RAR alpha. Changes in expression levels of PML/RAR alpha and ERG presented poor correlation. While, in other patients with relative low expression of BAALC transcripts (<7x10exp-3/GAPDH), ERG gene expression levels gradually decreased after the induction therapy and following consolidation treatments. In patients unable to attain remission, ERG expression levels remained high. Thus, the quantitation of the ERG gene expression made it possible to assess MRD in patients with acute leukemia (except for APL) carrying low BAALC expression. To our knowledge, this is the first report concerning the use of ERG mRNA expression for MRD monitoring.