Increased cellular infiltration within the PyV MT tumors of arthritic versus non-arthritic mice. A - F: H&E staining showing inflammation in the tumor microenvironment; A and D: PyV MT (Low inflammation); B and E: PyV MT + CII at 9 (severe inflammation); C and F: PyV MT + CII at 18 wks (severe inflammation). The images of tumor sections were taken at 200× (A-C) and 400× (D-F) magnification from the same area. Representative of n = 10 mice is shown. G-L: Increased macrophage infiltration within the PyV MT tumors of arthritic versus non-arthritic mice indicated by F4/80 staining. The images of the macrophage staining were taken at 600× magnification. Representative of n = 3 mice is shown.