Comprehensive study on ERG gene expression in normal karyotype acute myeloid leukemia: ERG expression is of limited prognostic value, whereas the accumulation of adverse prognostic markers stepwise worsens the prognosis

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

INTRODUCTION

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.

METHODS

In this study, we investigated expression level of both genes in 111 adult AML-NK at diagnosis and examined their prognostic potential.

RESULTS

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 NPM1^wt 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 BAALC^high /BAALC^low (21/21) and MN1^high /MN1^low (21/22) groups, we detected that BAALC^high /or MN1^high patients had a tendency toward lower complete remission rate. Also, survival analysis showed that BAALC^high /or MN1^high 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 BAALC^high /or MN1^high was only 5 months vs 25 months in BAALC^low /or MN1^low .

CONCLUSION

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.

A novel method for detecting the cellular stemness state in normal and leukemic human hematopoietic cells can predict disease outcome and drug sensitivity

Acute leukemia is an aggressive blood malignancy with low survival rates. A high expression of stem-like programs in leukemias predicts poor prognosis and is assumed to act in an aberrant fashion in the phenotypically heterogeneous leukemia stem cell (LSC) population. A lack of suitable genome engineering tools that can isolate LSCs based on their stemness precludes their comprehensive examination and full characterization. We hypothesized that tagging endogenous stemness-regulatory regions could generate a genome reporter for the putative leukemia stemness-state. Our analysis revealed that the ERG  + 85 enhancer region can serve as a marker for stemness-state and a fluorescent lentiviral reporter was developed that can accurately recapitulate the endogenous activity. Using our novel reporter, we revealed cellular heterogeneity in several leukemia cell lines and patient-derived samples. Alterations in reporter activity were associated with transcriptomic and functional changes that were closely related to the hematopoietic stem cell (HSC) identity. Notably, the differentiation potential was skewed towards the erythro-megakaryocytic lineage. Moreover, an ERG  + 85^High fraction of AML cells could regenerate the original cellular heterogeneity and was enriched for LSCs. RNA-seq analysis coupled with in silico drug-screen analysis identified 4HPR as an effective inhibitor of ERG  + 85^High leukemia growth. We propose that further utilization of our novel molecular tool will identify crucial determinants of LSCs, thus providing a rationale for their therapeutic targeting.

The clinical and prognostic significance of FIS1, SPI1, PDCD7 and Ang2 expression levels in acute myeloid leukemia

OBJECTIVES

The marked heterogeneity of acute myeloid leukemia (AML) renders precisely predicting patient prognosis extremely difficult. Genetic alterations, fusions and mutations, may result in misexpression of key genes in AML. We aimed to investigate the expression patterns of 4 novel genes; FIS1, SPI1, PDCD7 and Ang2 to determine their potential prognostic role in AML patients.

METHODS

Bone marrow mononuclear cells were analyzed for of FIS1, SPI1, PDCD7 and Ang2 expression levels by real-time quantitative PCR as well as of FLT3/ITD and NPM1 mutations in 100 newly diagnosed cytogenetically normal (CN-AML) patients, and 100 non-malignant controls.

RESULTS

FIS1, SPI1, PDCD7 and Ang2 were significantly overexpressed in CN-AML patients (p < 0.001). Their high expression levels were significantly associated with lower complete remission (CR) rate, shorter relapse-free survival (RFS) and overall survival (OS). On multivariate analysis, high FIS1 expression showed a significant impact on CR response after induction therapy (OR = 88.777, 95% C.I: 2.85-2765.78, p = 0.011) while high PDCD7 appeared to be an independent risk factor for RFS (HR = 5.107, 95% C.I: 1.731-15.066, p = 0.003) and OS (HR = 7.353, 95% C.I: 1.859-29.079, p = 0.004) in CN-AML patients.

CONCLUSIONS

FIS1 and PDCD7 expression are considered independent risk factors and should be integrated into the current AML stratification system.