Breast cancer xenograft tumors grew to an average maximal diameter of 7.1 ± 1.9 mm in luminal A breast cancers, 7.8 ± 2.3 mm in Her2+ breast cancers, and 7.9 ± 1.6 mm in triple-negative breast cancers. The gene discussed is ERBB2; the disease is triple-negative breast carcinoma.