LM2 proliferation correlates to the IGF-1 levels in macrophage conditioned media. A: IGF-1 and EGF levels in BALF from naïve or tumor-bearing animals, determined by ELISA. B: IGF-1 levels in media conditioned by untreated or IL-4 stimulated macrophages from naïve or tumor-bearing animals. C: Fold-change in LM2 cell number after addition of MØCM produced in (B), with untreated control LM2 cell numbers normalized to 1 (not shown). D: Pearson correlation and linear regression of MØCM IGF-1 levels vs. the fold-change in LM2 cell number after MØCM addition, P < 0.001. E: IGF-1 and EGF levels in cell line-conditioned media. Cell number was determined as described, and mean + SD plotted as fold-change from control. BALF IGF-1 levels in (A) from n = 12 mice per condition, and in vitro data (B-E) was pooled from at least 3 independent experiments. * P < 0.05, ** P < 0.01, *** P < 0.001 versus control, and # P < 0.01, ## P < 0.001 versus similarly treated naïve groups (A-C) or epithelial cell lines (E) by 2-way ANOVA.