EFS and breast cancer: The Cas family comprises four members: p130Cas/BCAR1 (p130 Crk-associated substrate; also known as Breast cancer anti-estrogen resistance 1 (BCAR1)), Nedd9 (Neural precursor cell expressed, developmentally down-regulated 9; also called Human enhancer of filamentation 1 (HEF-1) or Cas-L), EFS (Embryonal Fyn-associated substrate) and CASS4 (Cas scaffolding protein family member 4).