Our finding that BST-2 expression confers survival advantage to breast cancer cells in circulation, as demonstrated using competitive syngeneic experimental pulmonary metastasis, may link BST-2 to cancer cell resistance to hemodynamic stress, and support the already known fact that BST-2 mediates interactions between cancer cells and fibroblasts and promotes cancer cell resistance to anoikis. The gene discussed is BST2; the disease is breast cancer.