IL6R and breast cancer: We observed by Western blot that the castration-resistant DU145 cells that maintain active STAT-3 exhibited a higher expression of the IL6R compared to the other cell lines; In this sense, some studies have observed, particularly in breast cancer, that constitutive expression of STAT-3 is increased in the tumor tissue and is even associated with risk factors such as mammographic density, which is why it has been proposed as a prognostic factor for determining risk in patients [50].