Figure 3
Experimental metastasis and influence of the immune system. Fate of TV injected tumor cells. Lung sections of mice, TV injected with 105 G-2 cells and sacrificed at 1 h, 1 d, 1 week and 2 weeks post injection, stained for T-Ag expression (red; arrows). (A) and (B) 1 h post injection: cells have left the circulation and entered lung tissue, 20× magnification; (C) micrometastasis 1 week post injection; (D) metastasis 2 weeks post injection, 10× magnification. Scale bars = 100 μm (E) Tumor cell dissemination in immune deficient mice. NP8 and NSG mice were orthotopically transplanted with either 103 H8N8 or G-2 cells (H8N8 in NP8 n = 4, H8N8 in NSG n = 13, G-2 in NP8 n = 12 and G-2 in NSG n = 14). Mice were sacrificed at a tumor volume of 2 cm3 and different mouse organs were analyzed by PCR for the occurrence of DTC (HA-tag signal): mammary gland #2, #7, liver, spleen, lung, brain, blood, bone marrow left and right. In NP8 mice on average 2 out of 9 tissues were positive for DTC and in NSG mice 5 out of 9. Statistical analysis: unpaired t test. ** p = 0.0019, *** p < 0.0001.