RNA seq of pediartic patients in oneset of early T-cell precursor acute lymphoblastic leukemia

Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) develops from very early cells with the potential for both T-cell and myeloid differentiation. The ambiguous nature of leukemic blasts in ETP-ALL may lead to immunophenotypic alterations at relapse. Here, we address immunophenotypic alterations and related classification issues, as well as genetic features of relapsed pediatric ETP-ALL. RNAseq was performed with the primary goal of crypric gene fusions search within subcohorts of relapsed and non-relapsed patients with sufficient material available. Overall, 3 relapsed and 8 non-relapsed patients were tested. As a relsult, 1 relasped and 3 non-relapsed patients were found to carry leukemia-specific fusions, of those 3 were confurmed by FISH (2 cases of ETV6 rearrangements and one PICALM::MLLT10-positive case) while only one cryptic rearrangement was caught in a non-relapsed patient (BCL11B cryptic rearrangement negative by FISH). Other 7 patients were not found to carry any leukemia-specisic fusions. Whole bone marrow was taken from patients in the oneset of the disease with >80% bone marrow blasts. RNAseq was performed to search for cryptic leukemia-specific fusion transcripts.