The Clinical and Molecular Characterization of Distinct Subtypes in Adult T Cell Acute Lymphoblastic Leukemia.

T-cell acute lymphoblastic leukemia (T-ALL) is a clonal proliferative malignant disease characterized by abnormal T-cell development. The classification of T-ALL primarily hinges on immunophenotype, encompassing early T-cell precursor (ETP)-ALL, near-ETP-ALL, and non-ETP-ALL. We summarized clinical information from 117 patients, with genetic data available for 77 patients and transcriptomic data available for 24 patients. An ETP-like score model was established based on transcriptome, aiming to address the subjectivity in the current T-ALL immunophenotype classification. The retrospective analysis indicated that ETP immunophenotype was not a prognostic factor for T-ALL patients. Compared to non-ETP-ALL patients, ETP-like patients including ETP-ALL and near-ETP-ALL were more likely to carry MED12 gene mutations, which may predict a dismal outcome. Transcriptomic analysis suggested that T-ALL patients with different immunophenotypes were in accordance with the T-cell development trajectory, while ETP-like patients exhibited characteristics of early T-cell development. Finally, we established an ETP-like score model and confirmed its efficiency across four independent cohorts, with sensitivity exceeding 80%. And T-ALL patients with high ETP-like score were associated with poor prognosis. In conclusion, our study elucidated the clinical and molecular features of distinct subtypes of T-ALL patients, providing new valuable insights for T-ALL classification.