CA.1aj.9(redirected from carbonic anhydrase IX)
CA.1aj.9A gene on chromosome 9p12 that encodes a carbonic anhydrase, a zinc metalloenzyme that catalyses the reversible hydration of carbon dioxide. Carbonic anhydrases participate in various biological processes, including respiration, calcification, maintaining acid-base balance and bone resorption, as well as producing aqueous humour, cerebrospinal fluid, saliva and gastric acid. CA9 is a transmembrane protein and the only known tumour-associated carbonic anhydrase isoenzyme, and may be involved in cell proliferation and transformation.
CA9 is expressed in all clear-cell type renal cell carcinomas, but is not expressed in normal kidney or most other normal tissues.