Zeroing in on Tumor-Reactive TILs.

Adoptive cell transfer of tumor-specific T cells provides an effective strategy for cancer immunotherapy. An article in this issue provides a novel approach to refine this technology by identifying tumor-reactive T cells based on frequency and PD-1 expression. Cancer Immunol Res; 4(9); 719. ©2016 AACRSee article by Ascierto et al., p. 726. ©2016 American Association for Cancer Research.