<n0:ComplexDefinition xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:def-definition>A synthetic HLA-A2-restricted nonapeptide derived from proteinase 3 with potential use in cancer immunotherapy. Cytotoxic T lymphocytes (CTL) primed with proteinase 3 PR1 peptide attack leukemic cells that express proteinase 3 aberrantly. Proteinase 3 is a serine proteinase that activates progelatinase A and is involved in metastasis and angiogenesis. (NCI04)</n0:def-definition><n0:def-source>NCI</n0:def-source></n0:ComplexDefinition>