In particular, triggering of ICOSL by a recombinant soluble form of ICOS (ICOS-Fc) inhibits adhesiveness and migration of human umbilical vein endothelial cells (HUVECs) and several tumor-cell lines, and treatment of mice with ICOS-Fc inhibits the development of experimental lung metastases in the B16 melanoma model4,8. Here, ICOS is linked to melanoma.