Oncogenic lesions and molecular subtypes in adults with B‐cell acute lymphoblastic leukemia

B‐cell acute lymphoblastic leukemia (B‐ALL), a genetically heterogeneous disease, is classified into different molecular subtypes that are defined by recurrent gene rearrangements, gross chromosomal abnormalities, or specific gene mutations. Cells with these genetic alterations acquire a leukemia‐initiating ability and show unique expression profiles. The distribution of B‐ALL molecular subtypes is greatly dependent on age, which also affects treatment responsiveness and long‐term survival, partly accounting for the inferior outcome in adolescents and young adults (AYA) and (older) adults with B‐ALL. Recent advances in sequencing technology, especially RNA sequencing and the application of these technologies in large B‐ALL cohorts have uncovered B‐ALL molecular subtypes prevalent in AYA and adults. These new insights supply more precise estimations of prognoses and targeted therapies informed by sequencing results, as well as a deeper understanding of the genetic basis of AYA/adult B‐ALL. This article provides an account of these technological advances and an overview of the recent major findings of B‐ALL molecular subtypes in adults.