Placental bone morphogenetic protein (PLAB) gene expression in normal, pre-malignant and malignant human prostate: Relation to tumor development and progression

The second most common target of prostate-cancer metastasis is bone, and th e phenomenon of skeletal metastasis represents the incurable stage of disea se. Histologically, skeletal metastasis from prostate cancer is distinctive due to its osteoblastic nature. The osteoblastic bone metastasis shows ext ensive new bone formation. with possible involvement of the soluble growth factors secreted by tumor cells, such as bone morphogenetic proteins (BMPs) . In the present study, we analyzed the gene expression of one of the new m embers of the BMP family, placental bone morphogenetic protein (PLAB), In s itu hybridization studies showed high levels of this gene in normal prostat e. However, the gene is down-regulated during the progression of cancer at the primary site. The most significant finding was re-expression of the PLA B gene in osseous metastatic lesions. Our results demonstrate that tumor ce lls, when released from the primary site and after re-growth elsewhere, are capable of re-expressing specific genes that may play a different role at metastatic sites than at the primary site. (C) 2001 Wiley-Liss, Inc.