Effect of diets on the estrogen receptor, Her-2 oncogene, and progesterone receptor expression in DMBA-induced tumors. Tumors were isolated and tissue sections were prepared as described in the legend of Figure 6. Expression of estrogen receptor (ER), Her-2 oncogene (Her-2), and progesterone receptor (PR) were detected using specific anti-mouse antibodies. Slides were observed under an Olympus microscope at 50 × magnification. The quantitative analysis antigen expression is described in Table 3.