TJP1 and breast cancer: In addition, treatment of MDA-MB-231, MCF-7, and BT-474 human breast cancer cells with (-)-oleocanthal resulted in a marked increase in the levels of epithelial markers E-cadherin and zona occludens 1 (Zo-1) in the three cell lines, and decreased the expression of the mesenchymal marker vimentin in MDA-MB-231, compared to the vehicle-treated control groups (Figure 5B).