SNAI1 and breast cancer: In breast cancer cells, several studies have shown that hypoxia leads to an increase in the expression of two transcriptional repressors of E-cadherin, SNAIL1 and SLUG, by modulating the NOTCH1 signaling pathway [50,51,52], and HIF-1 transactivation of both the SNAIL1 and SLUG promoters has been demonstrated [53,54].