In this study, we found that up-regulation of SNAT1 was significantly associated with (1) tumor size, lymph node metastasis and advanced disease stage, the most important clinical determinants of treatment and prognosis for breast cancer; (2) Ki-67 overexpression and negative ER expression, the most important biomarker guiding treatment and outcome for breast cancer; (3) elevated activity of Akt, determined by the expression of phosphorylated Akt (p-Akt). This evidence concerns the gene MKI67 and breast cancer.