SLC2A1 and breast carcinoma: However, since some Nuc-pYStat5-positive breast cancer cases display heterogeneous staining patterns with regional intratumoral loss of Nuc-pYStat5 (for example Figure 1C), we determined at a more refined scale whether mutually exclusive expression of GLUT1 and Nuc-pYStat5 also existed at the regional level within tumors.