Illuminating the center: mechanisms regulating lumen formation and maintenance in mammary morphogenesis.

The lumens present in ductal structures are required for transport of fluids and air. Studies in model organisms and cells in culture suggest that lumens can be generated by multiple mechanisms including apoptosis of centrally located cells, and re-modeling of epithelia. Several studies point to a role for apoptosis during lumen formation in the mammary ducts. However, a role for other mechanisms during lumen formation in the mammary ducts is largely unexplored. Understanding how lumens are formed and maintained free of cells is of clinical importance because filling of the luminal space is associated with cancer and inflammation. Thus, further investigation can lead to new diagnostic and therapeutic opportunities.