Mechanisms involved in bone invasion by tumour cells.

Skeletal metastases are common in patients with breast and prostate cancer and cause considerable morbidity and aversely affects the quality of life (bone pain, pathological fractures, hypercalcaemia and nerve compression syndromes). In this paper emerging new concepts of breast cancer-bone interactions, in particular the involvement of angiogenesis and the role of cancer-induced bone resorption in skeletal metastasis are discussed.Because of the progress made in early detection and surgical treatment of the primary tumor, mortality in cancer patients is increasingly linked to metastatic disease. Bone is the second most common site of metastasis. and the frequency of bone metastases at autopsy of cancer patients varies between 60 % and 85 %, depending on the cancer type. Clinical and experimental observations indicate that the hematopoietic marrow, rather than the bone tissue, is the initial site of cancer cell seeding. Micrometastases in bone marow represent the pathophysiological basis of minimal residual disease that will eventually lead to cancer relapse as overt metastases. Understanding of the molecular events in bone metastasis is, therefore, a prerequisite for the evaluation of novel therapies aiming at repressing initial stages of metastatic growth. [ABSTRACT FROM AUTHOR]