PSAP and prostate cancer: The specific IHC markers for prostate cancer are NKX3.1, PSA, PSAP, PSMA, and P501S.[32–34] Furthermore, negative PSA does not exclude the prostatic origin especially in the case of undifferentiated tumors.[22] Finally, the expression of human Ki-67 protein and CD10 can also help to confirm suspected metastatic lesions.[35,36]