GDF2 and neoplasm: Charting of the tumorigenic progression demonstrated that RIP1-TAg2; Gdf2−/− mice presented with a 44% reduction in the number of tumors (Figure 4B, 5.2 ± 0.5 tumors /mouse in Gdf2-deficient mice, compared to 9.3 ± 0.8 for wildtype RIP1-TAg2 mice), and a 49% reduction in total tumor volume (Figure 4C, 19.9 ± 2.9 mm3/mouse in Gdf2-deficient mice, compared to 39.4 ± 8.2 for wildtype RIP1-TAg2 mice).