^p190BCR-ABL junctional neoantigen sequence that elicits T-cell responses. The BCR-ABL translocation results in the creation of a “neoantigen” located at the junction of both otherwise “self” proteins. This foreign amino acid sequence presented in the context of major histocompatibility complex molecules can elicit T-cell responses; in this issue, Comoli et al go on to demonstrate that patients with Ph⁺ ALL can derive a clinical benefit from infusions of BCR-ABL–reactive T cells.