In addition to bone stromal cells such as osteoblasts (hFOB) and bone marrow fibroblasts (HS27A), the results of the present study reveal an apparent upregulation of osteonectin mRNA expression in bone metastatic prostate cancer cells (C4-2B) as compared with their non-bone metastatic sublines (LNCaP and C4-2). This evidence concerns the gene SPARC and Familial prostate cancer.