Prostate specific antigen (PSA), placental alkaline phosphatase (PAP), S100, vimentin, alpha fetoprotein (AFP), calretinin, and leukocyte common antigen staining can be performed to exclude other types of tumors including metastatic prostate cancer, melanoma, sarcoma, testicular tumor, mesothelioma, and lymphoma. This evidence concerns the gene AFP and neoplasm of testis.