MMP2 and neoplasm: Reciprocal trans-activation of tumor cell matrix remodeling by the nearby stroma is also demonstrated by the fact that PANC-1 cells, epithelial tumor cells that exhibit very modest matrix degradation, can be activated to increase matrix remodeling via incubation with media from MMP2-secreting stromal cells, even though PANC-1 also express pro-MMP2 (S1 Fig).