Combination therapy of GU81 and doxorubicin prevents transition from a premalignant to an invasive phenotype. Tumor tissue was harvested, fixed in formalin, sectioned, and stained with hematoxylin and eosin. Images representative of at least 3 tumors from each group are shown. Note the dramatic reduction in the number of invasive cells induced by combination therapy. Total magnification 200×; scale bar, 50 μm.