(Elsevier) Mortality due to prostate cancer is usually related to its likelihood to metastasize, especially to bone. Prognostic biomarkers are urgently needed to predict disease aggression so that appropriate treatment can be selected. A report in The American Journal of Pathology, published by Elsevier, indicates that CCN3, a protein secreted into the extracellular matrix between cells, may be an important factor that promotes prostate cancer invasion of bone and may aid in identifying prostate cancer patients at higher risk of poor outcomes.