Activin-like receptor kinase 1 (ALK1) expression in tumor endothelial cells is a prognostic factor for metastasis of breast cancer, because pharmacologic targeting of ALK1 provided long-term therapeutic benefit in mouse models of mammary carcinoma, accompanied by strikingly reduced metastatic colonization (Cunha et al., 2015). The gene discussed is ACVRL1; the disease is breast cancer.