Higher invasion of PyV MT cells towards the bone and lung lysate of the arthritic versus non-arthritic PyV MT mice. Up regulation of several cytokines in the lung and tumor microenvironment. A and B: Significantly higher invasion index of the PyV MT tumor cells towards the arthritic bone and lung lysate in an in vitro matrigel invasion assay (* p < 0.05 compared to the non-arthritic PyV MT lung and bone lysate). C and D: A graphical representation of the up regulated cytokines in the bone and lung lysate (*p < 0.05, **p < 0.01, ***p < 0.001). The Ray Biotech cytokine array kit was utilized for this experiment. Average of n = 4 mice. The statistical differences between groups are shown with horizontal bars. We have compared 1) C57Bl/6 with C57Bl/6 + CII at 9 and 18 weeks; and 2) PyV MT with PyV MT + CII at 9 and 18 weeks.