Stem cells in disguise Epitope editing can empower targeted cancer immunotherapies

The discovery that our immune system not only provides constant surveillance against the development of neoplastic disorders but may also be artificially reprogrammed to recognize and eradicate established malignancies has transformed our perspective on oncology treatment and prognosis. The exploitation of monoclonal antibodies (mAbs) has paved the road to antigendirected targeting of cancerous cells and led to the development of chimeric antigen receptor (CAR) T cells. This revolutionary cellular therapy has demonstrated unprecedented efficacy in relapsed or refractory acute B-lymphoblastic leukemia, with up to 90% complete responses (1). These results were made possible by the high-level, uniform expression of the CD19 target antigen and the tolerability of B cell aplasia, whose sustained depletion is compatible with patients' long-term survival.