Figure 4: Recovered erbB2+ cells form mammary tumors. Dissociated cells from mixed mammary outgrowths were magnetically sorted for erbB2 prior to transplantation. A) ErbB2+ fraction formed mammary tumors when 1000 cells were transplanted even when fat pad contained host outgrowth (unstained ducts-add arrows). Tumors from two separate mammary recipients are shown. B) Cross sections analyses of mammary outgrowths shown in (A) demonstrating entire mammary tumors consist of lacZ+ cells. Sections counterstained with nuclear fast red. Scale bars = 100μm. Figure from Booth et al., 2010.