MMP2 and neoplasm: Zymography analysis of tumor homogenates showed no changes in overall expression levels of the gelatinases MMP-2 and MMP-9, though there was a slight reduction in the ratio of active MMP-2/pro-MMP-2 in heterozygote and null mice compared to their wild-type littermates at end-stage disease or 14 weeks of age (Figure 5B).