MDK and nasopharyngeal carcinoma: Using NPC cell lines transfected with lentivirus carrying miR-9, they found that HUVEC treated with miR-9-overexpressing exosomes showed decreased migration and tube formation, a reduced level of MDK (mRNA and protein), and the reduced activation of the downstream PDK1/AKT pathway, indicating the role of miR-9 as a suppressor of angiogenesis.