The proteins have many other similarities too: in the MCF7 breast cancer cell line, ANXA4 and ANXA5 were found to have similar mRNA expression levels, Ca2+ sensitivity and recruitment to membrane damage sites15; both bind to membranes as trimers, functioning to restrict phospholipids and other protein mobility on the membrane during repair16; as trimers, they self-assemble on membranes in 2D crystal arrays17; and, both proteins are central to differing mechanistic models of PMR. Here, ANXA4 is linked to breast cancer.