SNAI2 and breast cancer: Snail family transcriptional repressor 2 (SNAI2), also called SNAIL2 or Slug, is a classical EMT‐related transcriptional inhibitor with an N‐terminal SNAG domain and a C‐terminal DNA‐binding domain,21, 22, 23, 24 was negatively associated with ERα expression in both BC and lung cancer.25, 26