Using an engineered metastatic niche, we identified a 9‐gene signature (Dhx9, Dusp12, Fhl1, Ifitm1, Ndufs1, Pja2, Slc1a3, Soga1, Spon2) that successfully delineated metastatic breast cancer from nonmetastatic breast cancers including an invasive cell line without metastatic potential. This evidence concerns the gene MTCL2 and breast cancer.