Fig. 2

CCR2 expression in the host is crucial for monocytic-MDSC mediated tumor resistance to radiation. CCR2 knockout sensitized tumor to radiation treatment. Tumors grown in CCR2^−/− mice were more radiosensitive than tumors in WT mice, in both the a MC38, and b LLC tumor models. c CCR2 deficiency in hosts led to eradication of 60% of tumors by IR. d Neutralization of CCL2 could not achieve better tumor control by IR. e CD31 staining (left) and quantification (right) of tumors grown in WT or CCR2^−/− mice. Tumors were harvested and frozen sections were fixed and stained. CD31 positive cells in three DAPI positive fields from three mice were counted. Scale bar = 100 µm; **P < 0.01; *P < 0.05. Data are presented as mean ± s.e.m