UROC28， also known as PBOV1 (prostate and breast cancer overexpressed 1) or UC28， is a 135 amino acid cytoplasmic and nuclear protein that is expressed in colon， prostate， small intestine， testis and spleen， with lower expression in thymus， ovary and peripheral blood leukocytes. UROC28 is up-regulated in prostate， breast and bladder cancer， and is thereby considered a useful target for diagnosis and treatment of these cancers. UROC28 is encoded by a gene located on human chromosome 6， which contains 170 million base pairs and comprises nearly 6% of the human genome. Deletion of a portion of the q arm of chromosome 6 is associated with early onset intestinal cancer， suggesting the presence of a cancer susceptibility locus. Additionally， Porphyria cutanea tarda， Parkinson’s disease， Stickler syndrome and a susceptibility to bipolar disorder are all associated with genes that map to chromosome 6.