PEITC and ICI 182, 780 inhibit the proliferation of ER-positive breast cancer MCF7 (A) and H3396 (B) cells. MCF7 and H3396 cells in normal medium were treated with vehicle, 2.5, 5, or 10µM of PEITC or ICI 182, 780 for 6 days and then counted with a hemocytometer. A: * As compare to Vehicle group P<0.001; a, P<0.01, PEITC 2.5µM vs ICI 182, 780 2.5 or 5µM, PEITC 10µM vs ICI 182, 780 10µM; b, P<0.05, PEITC 5µM vs ICI 182780 5 or 10µM. B:* As compare to Vehicle group P<0.001; a, P<0.01, Vehicle vs. PEITC 2.5µM or ICI 182, 780 10µM; b, P<0.05, PEITC 5µM vs. ICI 182, 780 5µM, PEITC 10µM vs. ICI 182, 780 10µM. Experiments were repeated three times, and the means ± SE are shown.