Study the Influence of Arthritis on Breast Cancer-Associated Bone Metastasis

Metastasis is regulated not only by intrinsic genetic changes in malignant cells, but also by the microenvironment. Several studies have demonstrated that sites of chronic inflammation are often associated with the establishment and growth of various malignancies 1. A common inflammatory condition in humans is autoimmune arthritis AA that causes inflammation and deformity of the joints. Other systemic effects associated with arthritis include increased cellular infiltration and inflammation of the lungs 2. Several studies have also reported statistically significant risk ratios between AA and various malignancies including breast, lung, hematopoietic, nonmelanotic skin, kidney, and colon 3, 4 5,6. Despite this knowledge available for a decade, it has never been questioned if a site of chronic inflammation linked to AA creates a milieu that attracts tumor cells to home and grow in the inflamed bones and lungs which are frequent sites of breast cancer metastasis 7. The preference of breast cancer cells to grow in the bone and lung is underscored by the fact that 65-75 of patients with advanced disease develop metastases in these organs. Yet, it is not known why and how breast cancer cells prefer to colonize these organs. There are no methods to predict the risk of breast cancer-associated metastasis and current treatments have notable limitations.