Prognostic factors in acute myeloid leukemia

Construction and validation of key genes-related prognosis model in children with acute myeloid leukaemia

INTRODUCTION

To identify the differentially expressed genes of acute myeloid leukaemia (AML) and construct and verify a survival prognosis model combined with patient survival information.

METHODS

The TARGET database was searched to identify differentially expressed peripheral blood genes in children with AML and healthy children. A gene set functional analysis and pathway analysis were performed using gene ontology and the KEGG pathway. A prognostic model for children with AML was constructed using univariate Cox, LASSO Cox regression and multivariate Cox regression analyses. Time-dependent receiver operating characteristic (ROC) curves were adopted to assess the predictive capacity of the prognostic models.

RESULTS

In total, 1640 differentially expressed genes were screened (1119 upregulated and 521 downregulated genes). The differentially expressed genes were mainly involved in nutrient metabolism and cytochrome P450 metabolism. Six key genes related to the prognosis of AML, FAM157A, GPR78, IRX5, RP4-800G7.1, RP11-179H18.5 and RP11-61N20.3, were identified. Kaplan-Meier curves indicated that 3-year and 5-year overall survival was significantly higher in the low-risk group than in the high-risk group. The area under the ROC curve was 0.722. At different stages of AML, FAM157A and RP4-800G7.1 exhibited significant differences in expression. The expression levels of FAM157A were significantly decreased in AML, whereas the expression levels of GPR78, IRX5, RP4-800G7.1, RP11-179H18.5 and RP11-61N20.3 were significantly increased in AML.

CONCLUSION

A prognosis-related gene model of AML was successfully constructed, and the expression levels of the model genes varied with AML stage.

The validation and clinical significance of LPCAT1 down-regulation in acute myeloid leukemia

BACKGROUND

Overexpression of lysophosphatidylcholine acyltransferase 1 (LPCAT1) has been found in various solid cancers and is associated with disease progression, metastasis, and recurrence. However, the expression pattern of LPCAT1 in acute myeloid leukemia (AML) bone marrow remains unknown. The present study aimed to compare LPCAT1 expression differences in bone marrow samples from AML patients and healthy controls and assess the clinical relevance of LPCAT1 in AML.

METHODS AND RESULTS

LPCAT1 expression in bone marrow was significantly lower in AML than in healthy controls predicted by public databases. Furthermore, real-time quantitative PCR (RQ-PCR) validated that LPCAT1 expression in bone marrow was significantly down-regulated in AML compared to healthy controls [0.056 (0.000-0.846) vs 0.253 (0.031-1.000)]. The DiseaseMeth version 2.0 and The Cancer Genome Atlas analysis revealed that the LPCAT1 promoter was hypermethylated in AML, and there was a strong negative correlation between LPCAT1 expression and methylation (R = - 0.610, P < 0.001). RQ-PCR revealed that the frequency of LPCAT1 low expression was lower in the FAB-M4/M5 subtype than in the other subtypes (P = 0.018). The ROC curve revealed that LPCAT1 expression could serve as a potential diagnostic marker for differentiating AML from controls with an area under the ROC curve of 0.819 (95% CI 0.743-0.894, P < 0.001). In cytogenetically normal AML, patients with LPCAT1 low expression had significantly longer overall survival than those without LPCAT1 low expression (median 19 versus 5.5 months, P = 0.036).

CONCLUSIONS

LPCAT1 is down-regulated in AML bone marrow, and LPCAT1 down-regulation could be used as a potential biomarker for AML diagnosis and prognosis.

TBC1D16 predicts chemosensitivity and prognosis in adult acute myeloid leukemia (AML) patients

Acute myeloid leukemia (AML) is a hematopoietic disease with poor survival. Chemotherapy resistance is one of the determinant factors influencing AML prognosis. To identify genes possibly affecting the drug responses in AML, the Illumina Infinium MethylationEPIC (850K) was used to screen for differential DNA methylation loci between patients achieved complete remission (CR) or not (non-CR) after induction therapy in 37 AML patients. Then, 32 differentially methylated sites (DMS) were selected for replication in another 86 AML patients by next-generation sequencing. Nine sites including cg03988660, cg16804603, cg18166936, cg11308319, cg09095403, cg18493214, cg01443536, cg16030878 and cg10143426 were replicated. Analysis of the Gene Expression Omnibus (GEO) database showed that mRNA expression of TBC1D16 and HDAC4 was associated with AML prognosis. Methylation level of the cg16030878 in TBC1D16 3'-UTR correlated positively with TBC1D16 mRNA expression in samples both in the TCGA database and clinically collected in the study. Both higher cg16030878 methylation and higher TBC1D16 mRNA expression were associated with increased risk of non-CR and worse overall survival (OS) in AML patients. In AML cells, knockdown of TBC1D16 decreased cell proliferation and ERK phosphorylation levels, as well as increased sensitivity to mitoxantrone and decitabine indicated by IC₅₀. In patients with combined use of decitabine, those patients with CR showed significantly lower TBC1D16 mRNA expression. On the contrary, knockdown of TBC1D16 resulted in decreased sensitivity to cytarabine in U937 cells. Our findings implicated that TBC1D16 is a potential predictor for chemosensitivity and prognosis in adult AML patients.

MicroRNA-335/ID4 dysregulation predicts clinical outcome and facilitates leukemogenesis by activating PI3K/Akt signaling pathway in acute myeloid leukemia

MircoRNA-335 (miR-335) has been reported as a significant cancer-associated microRNA, which was often epigenetically silenced and acted as a tumor suppressor gene in diverse human solid tumors. Conversely, recent studies show that miR-335 overexpression was identified in both adult and pediatric acute myeloid leukemia (AML), suggesting that it might play an oncogenic role of miR-335 in AML. However, the role of miR-335 during leukemogenesis remains to be elucidated. MiR-335/ID4 expression was detected by real-time quantitative PCR and/or western blot. Survival analysis was performed to explore the association between miR-335/ID4 expression and the prognosis, and further validated by public databases. Gain-of-function experiments determined by cell proliferation, apoptosis, and differentiation were conducted to investigate the biological functions of miR-335/ID4. Herein, we found that miR-335 expression, independent of its methylation, was significantly increased and negatively correlated with reduced ID4 expression in AML. Moreover, aberrant miR-335/ID4 expression independently affected chemotherapy response and leukemia-free/overall survival in patients with AML. Gain-of-function experiments in vitro showed the oncogenic role of miR-335 by affecting cell apoptosis and proliferation in AML, and could be rescued by ID4 restoration. Mechanistically, we identified and verified that miR-335/ID4 contributed to leukemogenesis through activating PI3K/Akt signaling pathway. Collectively, aberrant miR-335/ID4 expression was an independent prognostic biomarker in AML. MiR-335/ID4 dysregulation facilitated leukemogenesis through the activation of PI3K/Akt signaling pathway.

Outcome of Childhood Acute Myeloid Leukemia With FLT3-ITD Mutation: The Experience of Children's Cancer Hospital Egypt, 2007-17

INTRODUCTION

The presence of FMS-like tyrosine kinase 3 (FLT3) internal tandem duplication (ITD) mutation in pediatric acute myeloid leukemia (AML) is associated with high rates of induction failure and worse survival. Its presence places the patient into a high-risk group. We aimed to describe the outcome of pediatric AML with FLT3-ITD mutation.

PATIENTS AND METHODS

We performed a retrospective analysis of cases of AML from July 2007 till July 2017 at Children's Cancer Hospital Egypt.

RESULTS

Seventy-one patients had FLT3 gene mutation out of 687 patients with AML. Sixty-five patients had FLT3 gene mutation with allelic ratio > 0.4; 43 (66.1%) of 65 patients experienced complete remission (CR). Of the 43 patients, 16 patients maintained CR, 18 patients relapsed after first CR, 8 patients died, and 1 patient was lost to follow-up. Patients with relapsing disease died after salvage chemotherapy, except for one patient, who was alive after second CR. Allogeneic bone marrow transplantation (allo-BMT) was performed for 9 (13.8%) of 65 patients in first CR, of whom 8 were alive and in CR, and 1 patient experienced disease relapse and died. Seven patients (10.7%) were alive without allo-BMT. Three years' overall and event-free survival for patients with FLT3-ITD mutation with high allelic ratio was 26.9% and 22.8%, respectively. Three years' overall and event-free survival for patients treated with allo-BMT was 77.8% and 78.8%, respectively, versus patients treated without allo-BMT, 16.3% and 12.8%, respectively.

CONCLUSION

FLT3-ITD mutation in pediatric AML was associated with poor treatment outcomes, and the survival of relapsing patients was extremely poor. Allo-BMT in first remission was the best treatment option. Alternative donor transplants and FLT3 inhibitors are needed to improve outcome in developing countries.

Overexpression of lncRNA PANDAR predicts adverse prognosis in acute myeloid leukemia

Background and purpose

Abundant studies have shown that lncRNA PANDAR plays an oncogenic role in human solid tumors. Although abnormal expression of PANDAR has been well investigated in solid tumors, it was rarely studied in hematologic diseases. Hence, the aim of this study was to determine the PANDAR expression level and its clinical significance in patients with acute myeloid leukemia (AML).

Materials and methods

For detecting the expression level of PANDAR in 119 AML patients and 26 controls, real-time quantitative PCR was used in this study. The prognostic values were evaluated by using Kaplan-Meier analysis, Cox regression analyses, and logistic regression analysis.

Results

PANDAR was significantly overexpressed in AML and might be a promising biomarker which could distinguish AML from normal samples (P<0.001). Patients with high expression of PANDAR (PANDAR ^high) were older and showed higher bone marrow blasts than patients in PANDAR ^low group (P=0.029 and 0.032, respectively). Significant differences between these groups were also detected regarding risk group and karyotype finding (P=0.009 and 0.041, respectively). Importantly, PANDAR ^high patients presented a significant lower complete remission rate compared to PANDAR ^low patients (P<0.001). Furthermore, Kaplan-Meier analysis showed that PANDAR ^high patients had shorter overall survival compared to PANDAR ^low patients observing the whole AML cohort, and also in the non-M3 group of patients (P<0.001 and P=0.005, respectively). Multivariate analysis of Cox and logistic regression analysis confirmed that high PANDAR expression was an independent unfavorable risk factor for overall survival and complete remission in both observed patient groups.

Conclusion

These results revealed that PANDAR was overexpressed in AML, and that higher PANDAR expression was associated with poor clinical outcome. Our study therefore suggests that PANDAR expression is a promising biomarker for prognostic prediction for AML.

Overexpression of CTNNB1: Clinical implication in Chinese de novo acute myeloid leukemia

Activation of Wnt/β-catenin signaling played a crucial role in tumorigenesis, and β-catenin (CTNNB1) overexpression has been identified in numerous solid tumors. The present study was designed to determine CTNNB1 expression and its clinical significance in Chinese de novo acute myeloid leukemia (AML) patients. Real-time quantitative PCR was carried out to detect the pattern of CTNNB1 expression in 140 AML patients and 46 controls. The level of CTNNB1 transcript in AML patients was significantly up-regulated compared with controls (P < 0.001). CTNNB1^high patients showed significantly older age than CTNNB1^low patients (P < 0.05). The frequency of high CTNNB1 expression was significantly observed in patients with intermediate/poor karyotypes. CTNNB1^high patients had a significantly lower complete remission (CR) rate than CTNNB1^low patients (P = 0.004). Among cytogenetically normal AML (CN-AML), CTNNB1^high patients presented significantly shorter overall survival (OS, P = 0.004) and leukemia-free survival (LFS, P = 0.038) than CTNNB1^low patients. Multivariate analysis confirmed that CTNNB1 expression was an independent prognostic factor for OS among CN-AML. Moreover, CTNNB1 expression level significantly decreased after CR stage (P = 0.032) and increased in relapsed stage (P = 0.015). Our findings suggest that CTNNB1 is overexpressed and confers a poor prognosis in AML, and could be used as a biomarker in monitoring disease recurrence.

High bone marrow ID2 expression predicts poor chemotherapy response and prognosis in acute myeloid leukemia

Dysregulation of ID proteins is a frequent event in various human cancers and has a direct role in cancer initiation, maintenance, progression and drug resistance. Our previous study has revealed ID1 expression and its prognostic value in acute myeloid leukemia (AML). Herein, we further reported ID2 expression and its clinical significance in AML. Real-time quantitative PCR was performed to detect ID2 transcript level in bone marrow mononuclear cells of 145 de novo AML patients. ID2 expression was significantly up-regulated in AML patients compared with controls. ID2 overexpression occurred with the highest frequency in poor karyotype (10/17, 59%), lower in intermediate karyotype (35/83, 42%), and the lowest in favorable karyotype (7/40, 18%). Moreover, high ID2 expression correlated with lower complete remission (CR) rate, shorter overall survival, and acted as an independent prognostic biomarker in whole-cohort AML and non-M3-AML patients. Importantly, the prognostic value of ID2 expression in AML was validated by The Cancer Genome Atlas (TCGA) data. In the follow-up of patients, ID2 expression at CR phase was decreased than at the time of diagnosis, and was increased again at the time of relapse. These findings demonstrated that bone marrow ID2 overexpression was a frequent event in AML patients, and predicts poor chemotherapy response and prognosis.

Epigenetic dysregulation of ID4 predicts disease progression and treatment outcome in myeloid malignancies

Promoter hypermethylation-mediated inactivation of ID4 plays a crucial role in the development of solid tumours. This study aimed to investigate ID4 methylation and its clinical relevance in myeloid malignancies. ID4 hypermethylation was associated with higher IPSS scores, but was not an independent prognostic biomarker affecting overall survival (OS) in myelodysplastic syndrome (MDS). However, ID4 hypermethylation correlated with shorter OS and leukaemia-free survival (LFS) time and acted as an independent risk factor affecting OS in acute myeloid leukaemia (AML). Moreover, ID4 methylation was significantly decreased in the follow-up paired AML patients who achieved complete remission (CR) after induction therapy. Importantly, ID4 methylation was increased during MDS progression to AML and chronic phase (CP) progression to blast crisis (BC) in chronic myeloid leukaemia (CML). Epigenetic studies showed that ID4 methylation might be one of the mechanisms silencing ID4 expression in myeloid leukaemia. Functional studies in vitro showed that restoration of ID4 expression could inhibit cell proliferation and promote apoptosis in both K562 and HL60 cells. These findings indicate that ID4 acts as a tumour suppressor in myeloid malignancies, and ID4 methylation is a potential biomarker in predicting disease progression and treatment outcome.

DLX4 hypermethylation is a prognostically adverse indicator in de novo acute myeloid leukemia

Hypermethylation of distal-less homeobox 4 (DLX4) has been increasingly identified in several cancers. Our study was aimed to determine the role of DLX4 methylation in regulating DLX4 expression and further analyze its clinical significance in de novo acute myeloid leukemia (AML) patients. DLX4 methylation level was detected by real-time quantitative methylation-specific PCR and bisulfite sequencing PCR. Treatment with 5-aza-2'-deoxycytidine (5-aza-dC) was used for demethylation studies. Clinical significance of DLX4 methylation was obtained by the comparison between the patients with and without DLX4 methylation. DLX4 was significantly methylated in AML patients compared with controls (P < 0.001). DLX4 methylation was negatively associated with DLX7 (the shorter DLX4 isoform) (R = -0.202, P = 0.021) but not BP1 (the longer DLX4 isoform) (R = -0.049, P = 0.582) expression in AML patients. DLX7 and BP1 messenger RNA (mRNA) were significantly increased after 5-aza-dC treatment in leukemic cell lines THP1 and Kasumi-1. DLX4 methylated patients showed significantly higher frequency of U2AF1 mutation compared with DLX4 unmethylated patients (P = 0.043). Both all AML and non-M3 patients with DLX4 methylation presented significantly lower complete remission rate than those with DLX4 unmethylation (P = 0.001 and <0.001, respectively). DLX4 methylated cases had significantly shorter overall survival than DLX4 unmethylated cases among both all AML (P = 0.003), non-M3 AML (P = 0.001), and cytogenetically normal AML (P = 0.032). Multivariate analysis confirmed that DLX4 methylation was independent risk factor in both all AML and non-M3 patients. Our study indicates that DLX4 hypermethylation is negatively associated with DLX7 expression and predicts poor clinical outcome in de novo AML patients.

Clinical impact of SNP of P53 genes pathway on the adult AML patients

INTRODUCTION

Acute myeloid leukemia (AML) is a highly heterogeneous disease, with biologically and prognostically different subtypes.

AIM

To study the impact of p53, p21, and mdm2 gene polymorphisms on the clinical outcome in adult AML patients treated at the National Cancer Institute (NCI) - Cairo University.

METHODS

Forty-eight adult AML patients presented to the Medical Oncology Department, NCI, from April 2010 till November 2011. Clinical data and bone marrow samples were obtained. Molecular genetic analysis involving P53, MDM2, and P21 single-nucleotide gene polymorphisms was done using polymerase chain reaction-restriction fragment length polymorphism coupled analysis.

RESULTS

The mean age was 35.7 years. After a median follow-up period of 12 months, 28 patients (58.4%) achieved complete remission (CR) and the overall survival (OS) was 8.7 months. Patients with homozygous Arg/arg at codon 72 of P53 had a better median OS months than Arg/Pro and Pro/Pro (13.4 vs. 8.4 vs. 1.5 months, respectively; P = 0.045). P53/p21 combination had a better median OS and disease-free survival (DFS) of 12.1 and 13.7 months for wild type cases (GG + Ser/ser) and 20.3 and 20.7 months for patients with either variant genes (GC + Ser/arg) compared with 1.1 and 1.9 months for patients with both variant genes (CC + arg/arg), (P = 0.037 and 0.004). The presence of wild genotype of either P21 or MDM2 may abolish the effect of P53 homozygous variant genotype on the OS. Neither p21nor mdm2 polymorphism alone showed an impact on OS or DFS. CR was not affected by any of the three gene polymorphisms.

CONCLUSION

The p53 pathway gene polymorphisms may affect the OS of adult AML patients.

Effect of small interfering RNA targeting wild-type FLT3 in acute myeloid leukaemia cells in vitro and in vivo

This study investigated the effect of using small interfering RNA (siRNA) to silence the wild-type FMS-like tyrosine kinase 3 (FLT3) gene in acute myeloid leukaemia (AML) cells, in vitro and in vivo. FLT3 siRNA was introduced into the human AML cell line, THP1, and into a THP1 xenograft tumour model in BALB/c nude mice. FLT3 siRNA effectively reduced both the mRNA and the protein levels of FLT3, arrested cells in G(0)/G(1) phase, inhibited THP1 cell proliferation and increased apoptosis. Intraperitoneal injection of FLT3 siRNA suppressed tumour growth in BALB/c nude mice. FLT3 siRNA treatment also reduced cyclin D1 and Bcl-2 protein levels, and increased the nuclear level of silencing mediator for retinoic acid and thyroid hormone receptors protein both in vitro and in vivo. These data suggest that FLT3 siRNA is a strong inhibitor of FLT3 expression in vitro and in vivo, and may provide a new therapeutic target for AML.

Prognostic factors in pediatric acute myeloid leukemia

Acute myeloid leukemia (AML), a heterogeneous group of diseases with variable responses to the same therapy, comprises nearly a quarter of childhood acute leukemias. Although historically very few prognostic markers have been incorporated into therapeutic decision making in AML, recent advances in technology have enabled identification of numerous factors associated with disease outcome. This review provides a detailed analysis of most clinically relevant factors associated with disease outcome in childhood AML.

Prognostic value of FLT3 mutations among different cytogenetic subgroups in acute myeloid leukemia

BACKGROUND

The impact of FMS-like tyrosine kinase 3 (FLT3) mutations and mutation burden among cytogenetic subgroups of patients with acute myeloid leukemia (AML) other than normal karyotype (NK) AML is unclear.

METHODS

Patients with newly diagnosed AML were divided among 3 cytogenetic subgroups: core binding factor (CBF) AML, NK-AML, and poor-risk AML.

RESULTS

In total, 481 patients were included: 13% had, CBF-AML, 57% had NK-AML, and 30% had poor risk AML, and the frequency of any FLT3 mutations was 20%, 32%, and 7.6% in the respective cytogenetic subgroups. FLT3 mutation did not have an impact on event-free survival (EFS) in patients with CBF-AML (P = .84) and poor-risk AML (P = .37). In patients with NK-AML, EFS was worse in the FLT3-internal tandem duplication (ITD) group (20 weeks vs 41 weeks; P < .00,001) but not in the FLT3-tyrosine kinase domain (TKD) point mutation group (61 weeks vs 41 weeks; P = .15). Worse EFS and overall survival (OS) were observed among patients with NK-AML and higher FLT3-ITD burden but not among patients with FLT3-TKD mutation. In multivariate analysis, FLT3-ITD mutation was prognostic of EFS in patients with NK-AML (hazard ratio, 3.1; P = .03).

CONCLUSIONS

FLT3 mutations did not have a prognostic impact in patients with AML who had good-risk and poor-risk karyotypes. In patients with NK-AML, FLT3-ITD mutations led to worse survival, which was even worse among patients who had high mutation burden.

Expression of S100A8 in leukemic cells predicts poor survival in de novo AML patients

Cytogenetic stratification remains insufficient for almost half of the acute myeloblastic leukemia (AML) cases, with AML patients requiring subsequent molecular investigation. In our study, we used mass spectrometry (MS)-based proteomic approaches to characterize de novo AML. Fifty-four samples (mononuclear cells from bone marrow or peripheral blood mononuclear cells collected and frozen before treatment) from two independent cohorts of newly diagnosed AML patients were analyzed. We showed that the protein signature of leukemic cells defined two clusters that displayed significant variation for overall and disease-free survival (P=0.001 and 0.0004, respectively). This proteomic classification refines the cytogenetic classes. AML patients with intermediate and unfavorable cytogenetic classifications could be subdivided according to their protein profiles into subgroups with significantly different survival rates. Among the proteins expressed by leukemic cells, we isolated a 10,800-Da marker that retained the highest discriminative value between living and deceased patients. The 10,800-Da marker was identified by MS peptide sequencing as S100A8 (also designated MRP8 or calgranulin A). Western blot analysis confirmed its expression mainly in AML patients with the worst prognosis, arguing for a selective deregulation associated with poor prognosis. These results suggest that the expression of S100A8 in leukemic cells is a predictor of low survival.

Adult acute erythroleukemia: an analysis of 91 patients treated at a single institution

Acute erythroleukemia (AML-M6) is an uncommon subtype of acute myeloid leukemia (AML); it is considered to have a poor prognosis. From 1 January 1980 to 21 May 2008, 91 patients with newly diagnosed AML-M6 were seen at the University of Texas-M.D. Anderson Cancer Center (UT-MDACC). Forty-five patients (50%) had a history of myelodysplatic syndrome (MDS), compared with 41% in our control group (patients with other AML subtypes) (P=0.08). Poor-risk cytogenetics were more common in patients with AML-M6 (61% versus 38%, P=0.001). Complete remission rates were 62% for patients with AML-M6, comparing with 58% for the control group (P=0.35). Median disease free survival (DFS) for patients with AML-M6 was 32 weeks, versus 49 weeks for the control group (P=0.05). Median overall survival (OS) of patients with AML-M6 was 36 weeks, compared with 43 weeks for the control group (P=0.60). On multivariate analysis for DFS and OS, AML-M6 was not an independent risk factor. AML-M6 is commonly associated with a previous diagnosis of MDS and poor-risk karyotype. The diagnosis of AML-M6 does not impart by itself a worse prognosis, and treatment decisions on this disease should be guided by well known AML prognostic factors.

Advanced acute myelogenous leukaemia (AML) during HAART-treated HIV disease, manifesting initially as a thyroid mass

A rare case report of acute myelogenous 46 XY, inv(16)(p13q22) leukaemia occurring in a patient with his HIV infection controlled by highly active antiretroviral therapy is reported, in the context of a review of the available literature evidences. The initial localization as an isolated thyroid mass has no clinical equivalents to date. Although at its initial presentation the haematological disease had a very advanced (M5) stage expressing a predominant monocytic phenotype, two 1-week cytotoxic chemotherapy cycles carried out with cytarabin-daunorubicin, achieved complete remission (as assessed by combined diagnostic imaging, and repeated bone marrow studies). At the present 11-month follow-up time, eventual bone marrow transplantation is under evaluation, since the chromosomal translocation was still present. A such favourable clinical response to acute, advanced myelogenous leukaemia with an insidious recognition is considered infrequent, especially in the setting of HIV disease.

Lineage-specific transcription factor aberrations in AML

Transcription factors play a key role in the commitment of hematopoietic stem cells to differentiate into specific lineages [78]. This is particularly important in that a block in terminal differentiation is the key contributing factor in acute leukemias. This general theme of the role of transcription factors in differentiation may also extend to other tissues, both in terms of normal development and cancer. Consistent with the role of transcription factors in hematopoietic lineage commitment is the frequent finding of aberrations in transcription factors in AML patients. Here, we intend to review recent findings on aberrations in lineage-restricted transcription factors as observed in patients with acute myeloid leukemia (AML).

The prognostic significance of leukemic cells clearance kinetics evaluation during the initial course of induction therapy with HAD (homoharringtonine, cytosine arabinoside, daunorubicin) in patients with de novo acute myeloid leukemia

The impact of the percentage of residual leukemic cells (RLCs) at the end of first course of induction chemotherapy (T1) or during aplasia (T2) on complete remission (CR) rate, disease-free survival (DFS), and overall survival (OS) were retrospectively analyzed in 72 cases of de novo acute myeloid leukemia (AML) treated with HAD (homoharringtonine, cytosine arabinoside, and daunorubicin) regimen. The patients were separated into two subgroups by a cutoff of 10% bone marrow leukemic cells at T1 or T2 time point. The CR rate, DFS, and OS were significantly different between the two groups. We further confirmed that the percentage of RLCs at T1 or T2 is an independent prognostic factor of AML.

Flt3 internal tandem duplication and P-glycoprotein functionality in 171 patients with acute myeloid leukemia

PURPOSE

Patients with adult acute myeloid leukemia (AML) with intermediate cytogenetics remain a heterogeneous group with highly variable individual prognoses. New molecular markers could help to refine cytogenetic stratification.

EXPERIMENTAL DESIGN

We assessed P-glycoprotein (Pgp) activity and Flt3 internal tandem duplication (ITD+) because of their known prognostic value and because they might lead to targeted therapy. We did a multivariate analysis on 171 patients with adult AML treated in the European Organization for Research and Treatment of Cancer protocols.

RESULTS

ITD+ and high Pgp activity (Pgp+) were found in 26 of 171 (15%) and 55 of 171 (32%) of all patients, respectively. ITD and Pgp activities were negative in 94 of 171 (55%, Pgp-ITD- group), mutually exclusive in 73 of 171 (43%, Pgp-ITD+ and Pgp+ITD- groups), and only 4 of 171 (2%, Pgp+ITD+ group) patients were positive for both. In multivariate analyses, Pgp+ITD+ (P < 0.0001) and age (P = 0.0022) were independent prognostic factors for the achievement of complete remission (CR). Overall survival (OS), CR achievement (P < 0.0001), WHO performance status (P = 0.0007), and Pgp+ITD+ status (P = 0.0014) were also independent prognostic factors. In 95 patients with intermediate cytogenetics, the CR rates of ITD+ patients were 40% versus 62% for ITD- (P = 0.099) and 41% versus 67% (P = 0.014) for Pgp+ versus Pgp- patients. In the Pgp-ITD- group (41 of 95), CR rates were 70% versus 44% for others (P = 0.012), OS achieved 48% versus 16% (P < 0.0001) and disease-free survival was 56% versus 27% (P = 0.024), respectively. Furthermore, the OS curves of the intermediate cytogenetics-Pgp-ITD- group were not significantly different from the favorable cytogenetic group.

CONCLUSION

Flt3/ITD and Pgp activity are independent and additive prognostic factors which provide a powerful risk classification that can be routinely used to stratify the treatment of patients with intermediate cytogenetic AML. ITD+ and Pgp+ patients should be considered for targeted therapy.

Cytogenetic findings and clinical outcomes of adult acute myeloid leukaemia patients

The role of cytogenetic findings in determining the diagnosis, therapy and prognosis of acute myeloid leukaemia (AML) has become more valuable by the day. In this study, the results of conventional and molecular cytogenetic analyses and clinical outcomes of 66 AML patients of different subgroups aged between 16 and 82 were evaluated. Chromosomal abnormalities were detected in 17 (25.7%) patients cytogenetically at the time of diagnosis, whereas molecular cytogenetic abnormalities were detected in 21 (31.8%) patients by fluorescence in situ hybridisation (FISH). Thirty-eight (57.6%) patients had a normal karyotype. In 8 patients, we did not obtain suitable chromosomes for karyotype analysis and in 3 patients conventional cytogenetics were not requested by the physician. During clinical follow-up, 21 patients (31.8%) achieved complete remission (CR), 2 had partial remission (PR) (3.0%) and 4 patients had progressive disease (6.06%). Twenty-eight (42.4%) patients died during treatment and no follow-up data were available in 7 cases. Among patients with chromosome abnormalities detected by either one of the two cytogenetic methods (n=28), 12 had achieved CR, 9 of whom were already categorised in the good prognostic group with t(15;17), inv16 or t(8;21). As for the normal karyotype, each patient displayed a different clinical course, which is probably due to the molecular changes in leukaemia-related genes. Here we report our findings, which correlate with previous reports and conclude that cytogenetics is a crucial marker in leukaemia diagnosis and conventional and molecular cytogenetics should be performed as well as molecular genetic diagnostic methods.

Normal hematopoietic function and multiple bone marrow clonal abnormalities in a patient with acute myeloid leukemia after two mismatched stem-cell transplants with graft failure and autologous reconstitution

A 13-year-old male with primary refractory acute myelogenous leukemia (AML-M0), underwent two mismatched stem cell transplantations (SCT) and experienced graft failure after both procedures. Of interest, his peripheral blood cell counts are normal 7 years after his first SCT, his bone marrow is morphologically normal, however, cytogenetic analysis reveals multiple recurring cytogenetic abnormalities. This is the third case of chromosomal instability with morphological normal marrow and peripheral blood to be reported, these rare cases suggest that hematopoietic stem cells must have compensating mechanisms that allow normal function despite extensive chromosomal damage, supporting the notion that normal marrow function is possible even with extensive chromosomal damage.

Advancement in characterization of genomic alterations for improved diagnosis, treatment and prognostics in cancer

Most human cancers are characterized by genetic instabilities. These instabilities manifest themselves as a series of genetic alterations, including discrete mutations and chromosomal aberrations. With the human genome deciphered, high-throughput technologies are rapidly advancing the field to generate genome-wide gene expression and mutation profiles that are highly correlative of biologic and disease phenotypes. While recent advancement in comprehensive genomic characterization presents an unprecedented opportunity for advancing the treatment of cancer, there are still many challenges that need to be overcome before we can fully utilize genomic markers and targets for cancer prediction, diagnostics, treatment and prognostics. This review describes recent advances in comprehensive genomic characterization at the DNA level, and considers some of the challenges that remain for defining the precise genomic portrait of tumors. Potential solutions that may help overcome these challenges are also offered.

DNA profiling analysis of 100 consecutive de novo acute myeloid leukemia cases reveals patterns of genomic instability that affect all cytogenetic risk groups

We have carried out a high-resolution whole genome DNA profiling analysis on 100 bone marrow samples from a consecutive series of de novo acute myeloid leukemia (AML) cases. After discarding copy number changes that are known to be genetic polymorphisms, we found that genomic aberrations (GA) in the form of gains or losses of genetic material were present in 74% of the samples, with a median of 2 GA per case (range 0-35). In addition to the cytogenetically detected aberration, GA were present in cases from all cytogenetic prognostic groups: 79% in the favorable group, 60% in the intermediate group (including 59% of cases with normal karyotype) and 83% in the adverse group. Five aberrant deleted regions were recurrently associated with cases with a highly aberrant genome (e.g., a 1.5 Mb deletion at 17q11.2 and a 750 kb deletion at 5q31.1). Different degrees of genomic instability showed a statistically significant impact on survival curves, even within the normal karyotype cases. This association was independent of other clinical and genetic parameters. Our study provides, for the first time, a detailed picture of the nature and frequency of DNA copy number aberrations in de novo AML.

C/EBPalpha and the pathophysiology of acute myeloid leukemia

PURPOSE OF REVIEW

The transcription factor C/EBPalpha controls differentiation and proliferation in normal granulopoiesis in a stage-specific manner. Loss of C/EBPalpha function in myeloid cells in vitro and in vivo leads to a block to myeloid differentiation similar to that which is observed in malignant cells from patients with acute myeloid leukemia. The finding of C/EBPalpha alterations in subgroups of acute myeloid leukemia patients suggests a direct link between critically decreased C/EBPalpha function and the development of the disorder.

RECENT FINDINGS

Conditional mouse models provide direct evidence that loss of C/EBPalpha function leads to the accumulation of myeloid blasts in the bone marrow. Targeted disruption of the wild type C/EBPalpha protein, while conserving the dominant-negative 30 kDa isoform of C/EBPalpha, induces an AML-like disease in mice. In hematopoietic stem cells C/EBPalpha serves to limit cell self-renewal. Finally, C/EBPalpha function is disrupted at different levels in specific subgroups of acute myeloid leukemia patients.

SUMMARY

There is evidence that impaired C/EBPalpha function contributes directly to the development of acute myeloid leukemia. Normal myeloid development and acute myeloid leukemia are now thought to reflect opposite sides of the same hematopoietic coin. Restoring C/EBPalpha function represents a promising target for novel therapeutic strategies in acute myeloid leukemia.

Multiple cellular antigen detection by ICP-MS

There is a great need in cell biology for the simultaneous detection of many intracellular and extracellular proteins within single cells. Current optical methods based on fluorescence activated flow cytometry are difficult to multiplex. We have developed a novel application of ICP-MS-linked metal-tagged immunophenotyping which has great potential for highly multiplexed proteomic analysis. Expression of intracellular oncogenic kinase BCR/Abl, myeloid cell surface antigen CD33, human stem cell factor receptor c-Kit and integrin receptor VLA-4 were investigated using model human leukemia cell lines. Antigens to which specific antibodies are available and are distinguishably tagged can be determined simultaneously, or multiplexed. Four commercially available tags (Au, Sm, Eu, and Tb) conjugated to secondary antibodies enable a 4-plex assay assuming that the primary antibodies are not cross-reactive. Results obtained by ICP-MS were compared with data from FACS. ICP-MS as an analytical detector possesses several advantages that enhance the performance of immunoassays, which are discussed in detail. Although multiplexing using metal-conjugated reagents is in a very early stage of research and feasibility studies, it is already apparent that more than four antigens could be accurately detected simultaneously using the ICP-MS instrument.