(A) Staining of distant tumors from young and old mice for LgT (green), Sca1 (red, top), or GRN (red, bottom). Cell nuclei counterstained with DAPI (blue). Graphs indicate number of Sca1+ cells or GRN+ cells recruited per LgT+ tumor cell. n=9 images for young; n=8 images for old. (B) Flow cytometry plots indicating gating strategy to isolate Sca1+/cKit- BMCs from cancer-free young (left) and old (right) mice. (C) Flow cytometric analysis of CD45+/Sca+/cKit- cells as a percent of total bone marrow in cancer-free and BPLER tumor-bearing young and old mice; n=4–6 per group. (D, E) Relative GRN (D) and CSF1R (E) mRNA in CD45+/Sca1+/cKit- BMCs isolated from indicated cohorts; values are relative to those for the identical cell population from cancer-free young mice (broken line); n=3 per group analyzed in triplicate. Data represented as mean ± SEM, analyzed using one-way ANOVA with Student’s t-test for significance; n.s.=not significant. See also Figure S3.