ACVRL1 (also known as ALK1) is a cell surface receptor in the TGF-beta signalling pathway which binds bone morphogenic protein (BMP)-9 and -10, appears to be involved in developmental and angiogenic blood vessel formation, and has been shown to be highly expressed in the vasculature and stroma in a high proportion of prostate tumours.52 Germline disruptive variants within ACVRL1 could therefore in principle inhibit development of new tumour vasculature and hinder the onset of metastases. This evidence concerns the gene ACVRL1 and prostate neoplasm.