CD324, also known as E-cadherin or cadherin-1, is a calcium-dependent cell adhesion protein that plays a crucial role in maintaining epithelial tissue integrity and regulating cell proliferation, differentiation, and survival. It is a member of the cadherin superfamily and is widely expressed on the cell surface of most epithelial tissues. The extracellular domain of CD324 facilitates homophilic binding between adjacent cells, while its cytoplasmic domain interacts with the actin cytoskeleton through catenins. This protein is essential for epithelial cell cohesion and acts as an invasion suppressor, with its loss often indicating high tumor aggressiveness in cancer.