Accordingly, we selected a set of proteins (LTBP3—Latent TGFβ Binding Protein 3; SNED1—Sushi, Nidogen and EGF-like Domains 1; EGLN1—Egl Nine homolog 1 and S100A2) based on the following criteria: they were (1) detected only in highly metastatic tumors; (2) secreted exclusively by the tumor cells; (3) in relatively high abundance (Figures 2 and 3D, Figure 2—source data 1, Figure 3—source data 1); (4) not previously investigated for any roles in metastasis. This evidence concerns the gene EGLN1 and neoplasm.