PTK2 and familial pancreatic carcinoma: Doxycycline can combine with the PAR1 key amino acid residues of Val257, Leu258, His336, His164, and Leu167, which inhibit PAR1 activity (25). In the present work, we showed that doxycycline can target PAR1 and inhibit the FAK/PI3K/AKT signaling pathway activation in pancreatic cancer cells, EMT, and the CSC-like properties of pancreatic cancer cells.