Differences of osteoblastic bone metastases and osteolytic bone metastases in clinical features and molecular characteristics

Several cancers tend to metastasize to bone, leading to osteolytic or osteoblastic bone lesions. The respective phenotypes of bone destruction and bone formation vary in clinical features, including incidence, prognosis, skeletal-related events and bone biomarkers. In addition, different molecular mechanisms explain the difference in phenotype. For example, molecules involved in osteolytic bone metastases (represented with breast cancer) include parathyroid hormone-related protein, transforming growth factor-beta, while in osteoblastic lesions (represented with prostate cancer), endothelin-1 and morphogenetic proteins, etc. play a more important role in bone formation. It is important for us to understand the differences of bone metastases between two phenotypes to help clinicians to understand the underlying mechanisms, behaviors and therapies in development and currently available for bone metastases.