The epithelium is the interface between the body and the external environment and covers all exterior surfaces and interior lumina. Depending on the tissue of origin, the functions of epithelial cells are diverse and include absorption, secretion, protection, transcellular transport, and sensation. Creative Bioarray offers a range of Epithelial Cells produced at Creative Bioarray's cell culture facility. The cells are isolated from normal human adult tissues of the airways (nasal mucosa, trachea, bronchi, and distal respiratory tract), breast (mammary gland), kidney (whole kidney and renal cortex), and the placenta (amniotic membrane). Shortly after isolation, all Creative Bioarray Human Epithelial Cells are cryopreserved at passage 2 (P2) using Creative Bioarray's proprietary, serum-free freezing medium, Cryo-SFM. Each cryo vial contains more than 500,000 viable cells after thawing. Proliferating cell cultures are made from 500,000 cryopreserved cells that have been thawed and cultured for three days at Creative Bioarray.