NKX3.1 is a protein encoded by the NKX3-1 gene and has
been found to be positive in the vast majority of primary prostatic
adenocarcinomas. A study has shown the sensitivity for identifying metastatic
prostatic adenocarcinomas was 98.6% (68/69 cases positive) for NKX3.1 and 94.2%
(65/69 cases positive) for prostate specific antigen (PSA). The specificity of
NKX3.1 was 99.7% in various cancers and stains nuclei in both normal and
prostate cancer. NKX3.1 antibody, used in combination with ERG monoclonal
antibody [9FY], may represent a superior combination to aid in identifying
tumors of prostatic origin.