In MCF-7 drug-resistant BC cells, an increase in HA production was observed due to the upregulation of HA synthase-2 (HAS2), while the upregulation of HAS2 contributed to the chemoresistance of cancer cells, as well as their ability to form drug-resistant spheres, through activation of the CD44/Nrf2 signaling pathway [75]. This evidence concerns the gene HAS2 and cancer.