ZEB1 and breast neoplasm: Conversely, E-Cadherin protein was not expressed in the MDA-MB-231 and SUM159 cell lines that have been defined as triple negative breast cancer cells with mesenchymal properties [18], while these breast tumor cells lines did express mesenchymal cadherins, either OB-cadherin or N-Cadherin respectively, in addition to expression of ZEB by both cell lines.