Cell line marker profiles correlate with established biomarkers in tumor xenografts. (a) Tumor growth curves of cell line-derived xenografts over time. Tumorigenicity of breast cancer cell lines was not correlated with their individual cellular profiles when injected into mammary glands of NOD/SCID mice. (b) Cell line marker profile correlated with resulting tumor histology and expression of biomarkers. Representative H&E stained sections of tumor xenografts from Luminal 1 and 2 cell lines (MCF7, SUM225) showing intraductal and comedo-like DCIS patterns of growth respectively, as well as, Basal cell line (HCC1806) showing solid carcinoma growth with squamous differentiation, and Mesenchymal cell lines (SUM159) showing spindle-cell metaplastic-like growth. Original magnification: 100×. Immunohistochemistry was used to stain tumor xenografts for expression of ERα, Her2, p53, CK14, CK18 and vimentin. Representative images shown from tumors of Luminal 1 (MCF7), Luminal 2 (MDA.MB.361), Basal (SUM 149), and Mesenchymal (MDA.MB.231) cell lines. Bar = 100 μm.