After the PET-scans, a biopsy of both regions was performed, revealing a metastasis of prostate adenocarcinoma in the os ilium (D, F; 100-fold magnification) and a metastasis of dedifferentiated prostate cancer in the os sacrum (E,G; 400-fold magnification) which was confirmed by immunohistochemical staining for NKX3.1 (detection of NKX3.1 (brown) in F, absence of NKX3.1 in G). The gene discussed is NKX3-1; the disease is Familial prostate cancer.