STAT3 and breast cancer: The breast cancer lines, MDA-MB-468 and MDA-MB-231, which harbor constitutively-active Stat3 [3,13], were used in both dose-response (treated with 0–5 μM H182 or H172 for 1 or 2 h) and time-course studies (treated with 1 or 3 μM H182 and H172, or 5 μM H120 and H105 for 0–24 h) to evaluate the effects of the inhibitors on Stat3 activation.