Cadherins are a family of calcium-dependent, cell-cell adhesion molecules that play an important morphoregulatory role in a wide variety of tissues. Alterations in cadherin function have been implicated in tumor progression in a number of adenocarcinomas. Cadherin-6 (CDH6), also known as K-cadherin (KCAD), is a type-II classic cadherin cell-cell adhesion molecules, which are expressed in graded or areal patterns, as well as layer-specific patterns, in the cortical plate. Human Cadherin-6 is synthesized as a 790 aa type I transmembrane glycoprotein that contains a 18 aa signal peptide, a 35 aa propeptide, a 562 aa extracellular region, a 21 aa transmembrane segment, and a 154 aa cytoplasmic domain. There are five cadherin domains of approximately 110 aa each in the extracellular region. Cadherin-6 is highly expressed in brain, cerebellum, and kidney, and may contribute to the formation of the segmental structure of the early brain, as well as the development of renal proximal tubules. Weak expression is also detected lung, pancreas, and gastric mucosa. Additionally, it is specifically expressed in the proximal tubule of normal kidneys and in renal cell cancer. Thus , Cadherin-6 is a new prognostic factor for renal cancer.
