HIF1A and cancer: STAT3 is crucial in advanced cancers because its activation can promote glycolysis by activating transcription of HIF-1α as well as transcriptionally activating HK2, in vitro [73,74] A comprehensive study utilizing in vivo and in vitro approaches in addition to patient samples, demonstrated that STAT3 mediated immune cell (NK cells) metabolism to resemble that of tumor cells, resembling the Warburg phenotype.