In this study, we used optical genome mapping (OGM), conventional karyotyping, and next-generation sequencing to analyze cytogenomic alterations in 91 cases of T-cell acute lymphoblastic leukemia/lymp Show more
In this study, we used optical genome mapping (OGM), conventional karyotyping, and next-generation sequencing to analyze cytogenomic alterations in 91 cases of T-cell acute lymphoblastic leukemia/lymphoma (T-ALL). Whereas karyotyping detected abnormal karyotypes in 55% of cases, OGM identified cytogenetic abnormalities in 97.8% of the cases and provided clinically relevant information beyond karyotyping in ∼70% of cases. OGM detected gene rearrangements in 80% of cases, including 24 recurrent gene fusions and 21 previously unreported putative gene fusions in T-ALL. Copy number variants were detected in 93% of cases, with interstitial deletions the most common. Gene mutations were detected in 93% of cases, with NOTCH1 being most frequent (in 57% of cases). Combining all data, most T-ALL cases harbored 3 or more cytogenomic aberrations. Specific cytogenomic alterations differed among T-ALL subtypes as follows: rearrangements of BCL11B and PICALM::MLLT10, deletions of 7p, and mutations involving DNMT3A, WT1, TET2, IDH2, and FLT3 were common in early T-precursor and near-early T-precursor subtypes. Rearrangements of TLX1, KMT2A, STIL::TAL1, and NUP214::ABL1, deletions of 9p, and FBXW7 mutations were frequently associated with the cortical subtype. We conclude that integration of OGM and next-generation sequencing with karyotyping enables comprehensive cytogenomic profiling of T-ALL that improves detection of clinically relevant genomic alterations and may inform disease classification and future studies of risk stratification. Show less
Studying mechanisms of malignant transformation of human pre-B cells, we found that acute activation of oncogenes induced immediate cell death in the vast majority of cells. Few surviving pre-B cell c Show more
Studying mechanisms of malignant transformation of human pre-B cells, we found that acute activation of oncogenes induced immediate cell death in the vast majority of cells. Few surviving pre-B cell clones had acquired permissiveness to oncogenic signaling by strong activation of negative feedback regulation of Erk signaling. Studying negative feedback regulation of Erk in genetic experiments at three different levels, we found that Spry2, Dusp6, and Etv5 were essential for oncogenic transformation in mouse models for pre-B acute lymphoblastic leukemia (ALL). Interestingly, a small molecule inhibitor of DUSP6 selectively induced cell death in patient-derived pre-B ALL cells and overcame conventional mechanisms of drug-resistance. Show less