Our data collected from DCIS.com cells (WT in regards to BRCA1/2 gene mutation status), cultured in various 3D cell culture models of extracellular matrix stiffness relevant to MD and within high MD cultivated in mice and in vivo in human breast tissue epithelia, relative to local stiffness measures, have revealed that RASSF1A gene and protein is increased with stiffness in these settings. The gene discussed is BRCA1; the disease is ductal breast carcinoma in situ.