Cbfbeta reduces Cbfbeta-SMMHC-associated acute myeloid leukemia in mice.

The gene encoding for core-binding factor beta (CBFbeta) is altered in acute myeloid leukemia samples with an inversion in chromosome 16, expressing the fusion protein CBFbeta-SMMHC. Previous studies have shown that this oncoprotein interferes with hematopoietic differentiation and proliferation and participates in leukemia development. In this study, we provide evidence that Cbfbeta modulates the oncogenic function of this fusion protein. We show that Cbfbeta plays an important role in proliferation of hematopoietic progenitors expressing Cbfbeta-SMMHC in vitro. In addition, Cbfbeta-SMMHC-mediated leukemia development is accelerated in the absence of Cbfbeta. These results indicate that the balance between Cbfbeta and Cbfbeta-SMMHC directly affects leukemia development, and suggest that CBF-specific therapeutic molecules should target CBFbeta-SMMHC function while maintaining CBFbeta activity.

The predictive value of lipoprotein lipase for survival in chronic lymphocytic leukemia.

BACKGROUND AND OBJECTIVES: The mutational status of the immunoglobulin heavy chain variable region genes (IGVH) is a strong indicator of prognosis in B-cell chronic lymphocytic leukaemia (CLL). Since the determination of the IGVH mutation status is very labor-intensive, alternative prognostically relevant markers would facilitate CLL diagnostics. DESIGN AND METHODS: Ten genes were selected from previously published gene expression profiling studies based on their differential expression in IGVH mutated versus unmutated cases of CLL, and tested with real-time quantitative polymerase chain reaction (RQ-PCR) in unpurified samples from 130 CLL patients. To ascertain potential contaminating effects by normal hematopoietic cells, the expression levels of the selected genes were determined in normal monocytes, B cells, T cells, NK cells and granulocytes. RESULTS: The selected genes, i.e., ZAP70, LPL, SPG20, ADAM29, NRIP1, AKAP12, DMD, SEPT10, TPM2 and CLECSF2, showed prognostic significance. In multivariate logistic regression analysis expression levels of LPL, ZAP70, ADAM29 and SEPT10 were the most predictive for IGVH mutational status. In univariate analysis the expression of LPL was the best predictor. For survival, expression of LPL was the strongest prognostic factor. In combination with the three cytogenetic markers associated with a poor prognosis, i.e., deletions 17p13, 11q22 and trisomy 12, expression of LPL and IGVH mutational status performed equally well with regard to their predictive value for survival, both being more predictive than ZAP70. INTERPRETATION AND CONCLUSIONS: This study demonstrates that LPL expression is a predictor for survival in CLL, and for this purpose is as good as IGVH mutational status and more reliable than ZAP70 expression when tested in unpurified CLL samples.

Addition of ß-mercaptoethanol is a prerequisite for high-quality RNA isolation using QIAsymphony technology as demonstrated by detection of molecular aberrations in hematologic malignancies.

The isolation of high-quality RNA and DNA from various specimens is essential to perform reliable molecular diagnostic assays. In routine diagnostics of hematologic malignancies isolation of high-quality RNA is a prerequisite. We used QIAsymphony technology (QST) using a customized RNA CT 800 V6 protocol for automated semi-high-throughput isolation of RNA from human specimens and compared the results for breakpoint cluster region-c-abl oncogene 1 (BCR-ABL1) quantification by real-time quantitative polymerase chain reaction (RQ-PCR) and detection of JAK2 V617F mutations by reverse-transcriptase PCR (RT-PCR) on QST RNA with RNA isolation performed with our routine manual method using RNA-Bee (RB). QST RNA was isolated with and without the addition of ß-mercaptoethanol (BME). Addition of BME to the lysis buffer RLT Plus resulted in consistently lower Ct values in analyses of the reference gene porphobilinogen deaminase (PBGD). Further, the BCR-ABL1 mRNA levels of the QST RNA isolation were highly consistent with RB RNA isolation, only when the lysis buffer RLT Plus in addition contained BME. Moreover, cases of myeloproliferative neoplasms (MPN) with low levels of JAK2 V617F mRNA were even missed in QST when lysis buffer RLT Plus was used, but they were readily detected after addition of BME.

Mutations in nucleophosmin (NPM1) in acute myeloid leukemia (AML): association with other gene abnormalities and previously established gene expression signatures and their favorable prognostic significance.

Mutations in nucleophosmin NPM1 are the most frequent acquired molecular abnormalities in acute myeloid leukemia (AML). We determined the NPM1 mutation status in a clinically and molecularly well-characterized patient cohort of 275 patients with newly diagnosed AML by denaturing high-performance liquid chromatography (dHPLC). We show that NPM1 mutations are significantly underrepresented in patients younger than 35 years. NPM1 mutations positively correlate with AML with high white blood cell counts, normal karyotypes, and fms-like tyrosine kinase-3 gene (FLT3) internal tandem duplication (ITD) mutations. NPM1 mutations associate inversely with the occurrence of CCAAT/enhancer-binding protein-alpha (CEBPA) and NRAS mutations. With respect to gene expression profiling, we show that AML cases with an NPM1 mutation cluster in specific subtypes of AML with previously established gene expression signatures, are highly associated with a homeobox gene-specific expression signature, and can be predicted with high accuracy. We demonstrate that patients with intermediate cytogenetic risk AML without FLT3 ITD mutations but with NPM1 mutations have a significantly better overall survival (OS) and event-free survival (EFS) than those without NPM1 mutations. Finally, in multivariable analysis NPM1 mutations express independent favorable prognostic value with regard to OS, EFS, and disease-free survival (DFS).