SLC2A1 and breast carcinoma: In oestrogen receptor positive (ER+) breast cancer, GLUT1-dependent glucose uptake is regulated by oestrogen stimulation; thus, ER activation upregulates GLUT1 mRNA expression and protein levels, as well as functionally regulating the activity of GLUT1 and 4 via Akt activation (Medina et al., 2003; Sun et al., 2014).