S100A8 and neoplasm: We found that serum S100A8/A9 was readily detectable in tumor-bearing mice and that, as tumors grew from 75-100 mm3 to approximately 200 mm3 in the 5-day treatment period (e.g., Fig. 4e), serum S100A8/A9 levels rose significantly in the vehicle group, whereas no such increase was seen in the serum of their GDC-0339-treated counterparts (Fig. 5c).