F2R and breast carcinoma: To verify whether doxycycline plays its inhibitory function in breast cancer cells through PAR1, thrombin was used to activate PAR1 in MCF-7 cells, E-Cadherin (a classical and most well-studied member of the cadherin superfamily, acting as a canonical epithelial marker) and Vimentin were detected with immunofluorescence assay [33].