To evaluate whether ADAM9-regulated ANGPT2 secretion from brain-metastatic lung cancer cells affects leakage of brain endothelial cells, conditioned media of control and ADAM9 knockdown cells was used to treat HBMECs, followed by detection of VE-cadherin, which is responsible for maintaining the restrictive barrier between endothelial cells18. The gene discussed is ADAM9; the disease is lung cancer.