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    Abstract:
    Abstract Objectives T cell acute lymphoblastic leukemia (T-ALL) defines a group of hematological malignancies with heterogeneous aggressiveness and highly variable outcome, making therapeutic decisions a challenging task. We tried to discover new predictive model for T-ALL before treatment. Methods A specific pipeline designed to discover aberrantly active genes was applied here on the RNA-sequencing data of 109 T-ALL patients from our multicenter clinical study. A prognostic classifying test, based on the detection of the combined expression of a subset of these genes was designed and further validated in an additional cohort of 32 adult T-ALL patients by using RT-qPCR. Results The expression of 18 genes was significantly associated with shorter survival, including ACTRT2, GOT1L1, SPATA45, TOPAZ1 and ZPBP (5-GEC), which were used as a basis to design a prognostic classifier for T-ALL patients. The molecular characterization of the 5-GEC positive T-ALL unveiled specific characteristics inherent to the most aggressive T leukemic cells, including a drastic shut-down of genes located on the mitochondrial genome and an upregulation of histone genes. These cases fail to respond to the induction treatment, since 5-GEC either predicted positive minimal residual disease (MRD) or a short-term relapse in MRD negative patients. Conclusion Overall, our investigations led to the discovery of a homogenous group of leukemic cells with profound alterations of their biology. It also resulted in an accurate predictive tool that could significantly improve the management of T-ALL patients.
    Keywords:
    Minimal Residual Disease
    Ectopic expression
    Acute lymphocytic leukemia
    In adult acute lymphoblastic leukemia (ALL) the complete remission (CR) rates have improved to 85% to 90%. Despite this high CR rate, 40% to 50% of patients eventually relapse. 1 This occurs because of the limited sensitivity of cytomorphology in assessing complete molecular remission. Thus, more sensitive methods that detect leukemic cells on a molecular level and identify minimal residual disease are needed.
    Minimal Residual Disease
    In adult acute lymphoblastic leukemia (ALL) the complete remission (CR) rates have improved to 85% to 90%. Despite this high CR rate, 40% to 50% of patients eventually relapse.1 This occurs because of the limited sensitivity of cytomorphology in assessing complete molecular remission. Thus, more sensitive methods that detect leukemic cells on a molecular level and identify minimal residual disease are needed.
    Minimal Residual Disease