Extracellular matrix in mammary gland development and breast cancer progression

Extracellular matrix (ECM) is one of the essential components of the tumor microenvironment. Increased ECM deposition has been detected in many types of solid tumors including breast cancer, in which the development and progression require extensive reorganization of ECM. The chemical and physical signals induced by ECM are necessary for breast cancer development and progression. Disturbing the fine balance of ECM signaling is very important in the long run to promote breast cancer development and progression. In this review, we summarized recent findings on functions of ECM microenvironment in mammary gland development, tumor growth, invasion, migration and metastasis, focusing on the functions of cancer cell-derived ECM in tumor progression. Our review showed that integrated biophysical and biochemical signals from ECM and soluble factors are crucial for normal mammary gland development and breast cancer progression.