As hypoxia is a key phenomenon in cancers,[18, 19, 20] and some known transcription factors critical for the Warburg effect, such as c‐Myc and SIX1, are modulated by hypoxia at the mRNA level,[8, 21] we used RNA sequencing (RNA‐seq) to identify transcription factors with unknown functions related to the inhibition of the Warburg effect in MCF7 human breast cancer cells under hypoxia or normoxia. This evidence concerns the gene SIX1 and breast cancer.