Having shown that loss of the myoepithelial EP300/MMP13 axis blocked invasion in β6 integrin-expressing spheroid models, we recapitulated this in our ductal model of DCIS (Fig. 6, Supplementary Fig. 6), where primary luminal and myoepithelial cells from reduction mammoplasty patients are recombined in Collagen-I to form breast ducts possessing an intact layer of myoepithelial cells31. Here, MMP13 is linked to ductal breast carcinoma in situ.