S100A9 and cancer: Expression of MMP239 and MMP940 is dependent on the intracellular calcium levels and in keeping with this, S100A8 and S100A9 could regulate their expression by modulating calcium concentration in cancer cells.41, 42 Indeed, we found that stimulation of MC38 and LLC cells with monocyte/macrophage-conditioned media, which induces S100A8 and S100A9 (Figures 2a and b), decreased intracellular calcium levels compared with unstimulated cancer cells.