As knock-down of endothelial PEAR1 and, depending on the tumor cell line, also CCL2 inhibited the ability of endothelial cells to induce tumor cell dormancy in vitro, we generated conditional knock-out mice lacking either PEAR1 or CCL2 in endothelial cells by crossing Pear1flox/flox or Ccl2flox/flox mice with Cdh5-CreERT2 mice (Suppl. The gene discussed is CCL2; the disease is neoplasm.