Human breast cancer cells are present in chimeric mammary outgrowths.

<p>Human breast cancer cells incorporated into the mammary gland and express human-specific mitochondria as indicated by arrows (A–D) (green; Alexa Fluor 488) and green fluorescent protein as demonstrated by immunoperoxidase (E–F) (brown, DAB). Human specific mitochondria is expressed in chimeric mammary gland outgrowths produced with A) MDA-MB-468 plus mammary epithelial cells transplant fragment; B) MDA-MB-231-GFP plus mammary epithelial cells transplant fragment; C) MDA-MB-231BRMS-GFP plus mammary epithelial cells transplant fragment; D) hTERT-HME1 plus mammary epithelial cells transplant fragment. Green fluorescent protein (GFP) as demonstrated by immunoperoxidase staining is expressed in chimeric mammary gland outgrowths generated using E) MDA-MB-231-GFP plus mammary epithelial cells transplant fragment; F) MDA-MB-231BRMS-GFP plus mammary epithelial cells transplant fragment. All outgrowths are second generation chimera transplants. Scale bars 40 µm.