Search

This article explores the effect of the PAX5/ETV6 fusion gene on precursor B transcription and on the PAX5 and ETV6 physiological pathways. It reveals a modulation of genes responsible for extracellular binding and intracellular signaling, thus supporting the role of PAX5/ETV6 in adhesion. It concludes that the opposite dominance of PAX5/ETV6 over endogenous PAX5 and the specific transcription profile are responsible for aberrant mechanisms essential in the leukemic transformation.

Pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL) has achieved an 80% cure rate as a result of a risk-adapted therapy largely based on minimal residual disease (MRD) monitoring. However, relapse is still the most frequent adverse event, occurring mainly in the patients with intermediate MRD levels (intermediate risk, IR), emphasizing the need for new prognostic markers. We analyzed the prognostic impact of cytokine receptor-like factor 2 (CRLF2) over-expression and P2RY8-CRLF2 fusion in 464 BCP-ALL patients (not affected by Down syndrome and BCR-ABL negative) enrolled in the AIEOP-BFM ALL2000 study in Italy. In 22/464 (4.7%) samples, RQ-PCR showed CRLF2 over-expression (20 times higher than the overall median). P2RY8-CRLF2 fusion was detected in 22/365 (6%) cases, with 10/22 cases also showing CRLF2 over-expression. P2RY8-CRLF2 fusion was the most relevant prognostic factor independent of CRLF2 over-expression with a threefold increase in risk of relapse. Significantly, the cumulative incidence of relapse of the P2RY8-CRLF2+ patients in the IR group was high (61.1%±12.9 vs 17.6%±2.6, P<0.0001), similar to high-risk patients in AIEOP-BFM ALL2000 study. These results were confirmed in a cohort of patients treated in Germany. In conclusion, P2RY8-CRLF2 identifies a subset of BCP-ALL patients currently stratified as IR that could be considered for treatment intensification. [ABSTRACT FROM AUTHOR]

The identification of prognostically relevant fusion genes is required in the routine diagnostic process of most advanced clinical protocols for leukemia patients, either for risk stratification, target-specific treatments, and/or as markers for monitoring Minimal Residual Disease during treatment. However, there is emerging need to implement diagnostics and patient classification based on other biological features, such as expression levels of specific genes or genomic polymorphisms and/or mutations. This advancement would ideally be pursued in a diagnostic laboratory by an unique platform capable of different diagnostic purposes. We developed a rapid, accurate and reproducible assay to screen for the most common fusion gene transcripts in human leukemia, which combines a multiplex RT–PCR approach with the electronic hybridization and fluorescent detection on the Nanogen NanoChip Molecular Biology Workstation. This study demonstrates, as a proof-of-principle, that this microelectronic device, highly effective in detecting single base mutations, is also efficient in the analysis of gene expression, thus providing as a multi-purpose platform for relevant comprehensive diagnostics of hemato-oncology patients.Leukemia (2008) 22, 294–302; doi:10.1038/sj.leu.2404987; published online 18 October 2007 [ABSTRACT FROM AUTHOR]