Seminoma : OCT3/4 Immunostain
OCT3/4 is a transcriptional regulator that is expressed in embryonic stem cells and germ cells. It is a quite sensitive and a specific marker of both seminoma and embryonal carcinoma (positive in >98% of cases). The staining pattern is nuclear as seen in this image. OCT3/4 expression is also seen in intratubular germ cell neoplasia, unclassified.