The bone remodeling environment is a factor in breast cancer bone metastasis

The bone microenvironment is clearly an important determinant of breast cancer metastasis to bone. Once established in bone, the ability for breast cancer cells to hijack normal regulatory pathways for osteoclast differentiation, activation, and survival is known to form the basis of a vicious cycle that promotes both bone destruction and tumor growth. However, the importance of the background remodeling activity in the early stages of breast cancer metastatic establishment in bone has not been systematically investigated. Here we review recent studies that indicate that bone remodeling levels, as influenced by calcium and vitamin D status, do impact the ability of human breast cancer cells to grow in the bones of nude mice. These studies support the assessment and correction of calcium and vitamin D deficient states in women at risk of developing advanced breast cancer.