ROR1 and neoplasm: In response to fatal bone marrow (containing ROR1+ stromal cells) failure caused by ROR1 specific CAR-T in mouse models, Srivastava et al. designed a CAR-T with a EpCAM or B7-H3 (antigens expressed on ROR1+ tumor cells but not ROR1+ stromal cells) specific synNotch receptor to enhance selectivity, which permitted both the safe targeting of tumor cells sufficiently separated from normal cells and the prevention of potential on-target off-tumor effects [85].