Recruitment of CD8+, CD4+, and Foxp3+ cells into oral lesions in response to anti–PD-1 treatment. Recruitment of CD8+, CD4+, and Foxp3+ cells into oral lesions in response to anti–PD-1 treatment. A, IHC staining for CD8, CD4, and Foxp3 in low-grade oral lesions induced by 4-NQO in control and anti–PD-1–treated mice. B and C, Quantification of the number of positive cells for the indicated markers in low-grade (B) and high-grade lesions (C). *, P < 0.05; ***, P < 0.001. Jin Wang et al. Cancer Prev Res 2017;10:684-693 ©2017 by American Association for Cancer Research