Frequencies of immune cell types show much stronger variations between tumor types in the tumor infiltrate compared with the spleen and tumor-draining lymph nodes. Frequencies of immune cell types show much stronger variations between tumor types in the tumor infiltrate compared with the spleen and tumor-draining lymph nodes. Flow cytometric analysis of the immune cell composition of (A and B) the spleen, (C and D) the tumor-draining lymph node (or inguinal lymph nodes in naïve mice) and (E and F) the tumor of mice bearing (A, C and E) 3 BALB/c models (CT26, RENCA and 4T1) or control naïve Balb/c mice and of mice bearing (B, D and F) 3 C57BL/6 models (MC38, LL/2, and B16F10 AP-3) or control naïve C57BL/6 mice, showing frequencies of 9 immune cell types (as percentages of CD45+ cells). n ≥ 6 mice per group. Data is representative of trends observed in at least 2 independent experiments. Suzanne I.S. Mosely et al. Cancer Immunol Res 2017;5:29-41 ©2017 by American Association for Cancer Research