CD5 and acute lymphoblastic leukemia: T-ALL is a highly heterogeneous disease, which can be categorized into four distinct stages: pro-T (CD7+, CD2-, CD5-), pre-T (CD7+, CD2+, CD5±), cortical-T (CD1a+), and mature T (sCD3+, CD1a-).19 The conventional T-ALL treatment regimen involves intensive therapy with multiple drugs, however, there is still a significant gap in achieving complete cure for T-ALL, especially in ETP-ALL.20–22 Therefore, the development of novel targeted therapeutic strategies and the improvement of prognosis, especially in adult T-ALL patients, is particularly urgent.