The lack of increased metastatic tumor growth in the lungs persuades us to speculate that tumor cells expressing monomeric BST-2 may alter the tumor environment landscape by changing the type of immune cells that are recruited to the tumor microenvironment because of changes in the expression of signaling cytokines and chemokines.29, 30, 31 It is also possible that cells expressing monomeric BST-2 may not survive in circulation thus limiting the number of cancer cells that may reach metastatic sites. The gene discussed is BST2; the disease is cancer.