Immunoanalysis on human xenografts. A. Fluorescent immunohistochemistry was performed on MCF7, MDA-MB-231, or T47D cells which were injected into the cleared fat pads of nude mice; once tumors reached 1 cm2 (measured in two dimensions), they were excised, formalin fixed, sectioned, and stained with the indicated PRLR isoform specific antibodies. B. Immunohistochemical analysis using DAB as chromogen of MCF7, MDA-MB-231, or T47D xenograft tumors. neg = no primary antibody as negative control; DAPI stain to visualize the presence of cells. Photographs are representative from 5 different tumors for each cell line. Magnification 40×.