Because there is limited information on prostate cancer brain metastasis, we reviewed our results by comparing data available from the literature on tumor growth in brain either from brain tumors or tumors metastasized to brain from lung or breast cancers, and from our own dataset of RANKL- or KRT13-expressing LNCaP cells, with the former metastasizing to the bone and soft tissues but not the brain, and the latter metastasizing to both bone and brain. This evidence concerns the gene KRT13 and breast cancer.