STAT5B and breast adenocarcinoma: To analyze whether NPQ-C6 was also able to downregulate cytokine-induced STAT5/3 activities, we used a human breast adenocarcinoma cell line (T47D) which fails constitutively active STAT but is able to respond to GH and IL6, which are activators of STAT5 and STAT3 signaling pathway, respectively (Shiu and Paterson, 1984; Badache and Hynes, 2001).