MMP13 and neoplasm: We observed a decrease in the percentage of tumor cells that had extravasated in the MMP13−/− mice compared to that of the wildtype mice which was not significant at 24 hours (P = 0.06 using 2-tailed t-test) but became significant at 48 hours(P = 0.02 using 2-tailed t-test) post tumor cell injection (Figure 3b).