A decrease or loss of STAT1 signaling activity has been reported in many types of cancer, such as colon cancer [8], breast cancer [12], leukemia, and melanoma [13] and a correlation between the high expression of STAT1 and good prognosis has been observed in colorectal [14,15], pancreatic [16], and esophageal cancers [17]. Here, STAT1 is linked to breast cancer.