Described herein are methods and systems using ADAM30 as a biomarker to help early diagnosis of congenital malformed vasculatures in children and which can also serve as a companion diagnostic biomarker for malformed vasculatures, as well as a subpopulation of cancer cells, wherein blockage of activity of ADAM30 by a neutralized antibody or inhibitor can be used as a treatment strategy for those ADAM30-positive vascular endothelial cells and cancer cells.