SLC2A1 and neoplasm: Additionally, it can also up-modulate the expression of GLUT1 [438], as well as that of the monocarboxylate transporters, MCT1 and MCT2, through transcriptional repression of microRNAs (miR-29a and miR-29c), to control toxic levels of lactate within tumour cells [439] (figure 3B.3).