Patent ID: 7294471

Claim:
A method for purifying cancer-specific Proliferating Cell Nuclear Antigen (csPCNA) comprising the steps of: (A) obtaining a tissue or body fluid sample comprising csPCNA; (B) contacting said sample with a peptide comprising the amino acid sequence LeuLysGlnLeuAspAlaGlnGlnThrGlnLeuArgIleAspSerPhePheArgLeu AlaGlnGlnGluLysGluAspAlaLysArg (SEQ ID No: 1), wherein said peptide is immobilized on a solid support and binds to said csPCNA to form a peptide-csPCNA complex; and (C) isolating csPCNA from said peptide-csPCNA complex so as to purify said csPCNA.