In particular, exposure to hypoxia poses a hurdle for transcriptomic studies, since it has been shown to modulate the transcription of classical and widely explored reference genes, namely glyceraldehyde-3-phosphate dehydrogenase (GAPDH), β-actin (ACTB), and β-tubulin (TUBB) in several cancer cell lines [22–26]. This evidence concerns the gene GAPDH and cancer.