Immunostaining for most of the usual testicular germ cell tumour markers is negative ( " i . e . placental alkaline phosphatase ( PLAP ), vimentin, actin, desmin, alpha fetoprotein ( AFP ), OCT4, human chorionic gonadotropin ( hCG ), and carcinoembryonic antigen ( CEA ) ).
42.
When GIST is suspected & mdash; as opposed to other causes for similar tumors & mdash; the pathologist can use immunohistochemistry ( specific antibodies that stain the molecule CD117 [ also known as " c-kit " ] & mdash; see below ) . 95 % of all GISTs are CD117-positive ( other possible markers include CD34, DOG-1, desmin, and vimentin ).