MMP11 and neoplasm: In a study using a MMTV-Ras transgenic mouse model of breast cancer, tumor formation was delayed and the number and tumor size of the primary tumor were lower, but a higher number of metastases were observed in MMP-11-deficient mice than in wild-type mice, indicating that MMP-11 promotes tumorigenesis in the early stages of breast cancer but inhibits the metastasis of tumor cells in the late stage of breast cancer (86).