It is potentially relevant that MMP-3, which is one of the central mediators of postlactational involution [55], a process associated with increased cancer risk in premenopausal women [56, 57], induces in cultured mammary epithelial cells transcriptional responses similar to those found in aggressive, basal, pregnancy-associated breast cancers [56, 58]. Here, MMP3 is linked to breast carcinoma.