This is observed, for example, in a study using MMP-9 gene knockout in an animal model; there was a lack of MMP-9-delayed tumorigenesis in the C3(1)-Tag model of basal-like triple-negative breast cancer, but there was no effect on tumorigenesis in the (MMTV)-Neu model of luminal breast cancer [33]. Here, MMP9 is linked to breast carcinoma.