Figure 6. Tumor-associated macrophages are involved in lung tumor formation.

Bone- marrow-derived macrophages (BMDM) were pulsed for 1 hour with LPS (0.1 μg/ml) or PBS before adoptively transferred into N-methyl-N-nitroso urea (NMU)-exposed C57BL/6 mice; LPS-BMDM inoculation slightly increased tumor lesion in the lung of tumor-bearing mice (A). The depletion of macrophages by means of intraperitoneal administration of clodronate-liposome reduced lung tumor formation in a dose-dependent manner (B). Data represent means ± SEM, (n = 12). Statistically significant differences are denoted by *, **and ***indicating p < 0.05, p < 0.01, and p < 0.005, respectively, as determined by ONE-WAY ANOVA and Student's t test.