ESR1 and breast cancer: To further study the relationship between increased α-actinin-1 and E-cadherin in basal-like breast cancer cells, we re-expressed GFP (control) or GFP-tagged E-cadherin (+ E-cadherin) in mesenchymal-like MDA-MB-231 cells, which lack ER and E-cadherin expression and have high α-actinin-1 levels (ER-/high A1/Ecad-).