Prostate cancer commonly gives rise to BM and prostate cancer cells induce the transition from endothelial cells to osteoblasts by releasing BMP-4 in the bone marrow [98,113]; however, this issue is far from being clarified because in most patients both lytic and sclerotic BM are present, suggesting that a real boundary between the two mechanisms cannot be actually identified [114]. Here, BMP4 is linked to prostate cancer.