As expected, in untreated mice bearing T1525 tumors immunohistochemistry and immunofluorescence showed strong MMP9 production by infiltrating MCs and not by T1525 tumor cells (Figures 5C,D and Supplementary Figure 2), whereas in T23 tumors MMP9 was mild and diffusely expressed by tumor cells and no infiltrating MCs were detected (Figures 5E,F). The gene discussed is MMP9; the disease is neoplasm.