As ascertained by ChIP-seq data of human endothelial cells, stimulation with the high-affinity ligand BMP9 produced a strong binding peak of SMAD1 in the promoter region of CLEC14A. To confirm this type of regulation, dual RNAscope-ISH on human breast cancer samples unveiled that expression of ACVRL1 is required for the concurrent detection of CLEC14A in the same cell. This evidence concerns the gene GDF2 and breast carcinoma.