Our results show that high STAT1 mRNA expression is not significant with OS in breast cancer patients (HR =0.94 (0.76–1.17), P=0.58), but significant with high pathological grade (HR =0.55 (0.39–0.77), P=0.00041), which indicated that STAT1 can be a prognostic marker for higher stage of breast cancer patients. Here, STAT1 is linked to breast cancer.