Some studies demonstrate that activated STAT1, as a tumor suppressor, is lost in several types of malignant cells (Adámková et al., 2007), including breast cancer (Koromilas and Sexl, 2013), lung cancer (Chen et al., 2015), and esophageal squamous cell carcinoma (Zhang et al., 2014), and many reports indicate that high STAT1 expression means better clinical prognosis (Widschwendter et al., 2002; Deng et al., 2012; Hosui et al., 2012). Here, STAT1 is linked to breast cancer.