They bind to cells such as fibroblasts, macrophages, endothelial cells, and kidney epithelial cells. Fibroadenomas are benign breast tumours characterized by an admixture of stromal and epithelial tissue. The bipotential hepatoblasts begin differentiating into biliary epithelial cells and hepatocytes. Tumours originating from the thymic epithelial cells are called thymomas. MICA and MICB are expressed on the surface of epithelial and endothelial cells. P1 is a membrane associated protein that allows adhesion to epithelial cells. Carcinoma is a type of cancer that occurs in epithelial cells. Areas of squamous metaplasia and epithelial pearls may be present. Modified tight junctions between epithelial cells control fluid release. The choroid plexus consists of many capillaries, separated from the ventricles by choroid epithelial cells. Experimental research has targeted adhesion molecules known as selectins on epithelial cells. The medication binds to the surface of the intestinal epithelial cells. Cell junctions are especially abundant in epithelial tissues. These enzymes are present in the cytoplasm of the epithelial cells. Cell junctions are well employed in epithelial tissues.