ALPG and seminoma: Placental-like alkaline phosphatase (PLAP) was one of the earliest markers studied, with high circulating levels initially identified in seminoma patients.[17] This led to its investigation as an immunohistochemical marker, where it was found to stain 98% of seminomas, 97% of embryonal carcinomas and 98% of ITGCN specimens with no staining of normal testicular tissues.[18] Since then a number of other immunohistochemical markers have been discovered to share expression in ITGCN and TGCT but not normal testes.