PTK2 and exocrine pancreatic carcinoma: IHC staining of tumors with antibodies to the FAK tyrosine-397 (pY397) autophosphorylation site revealed general increased stromal FAK pY397 staining in pancreatic carcinomas (13), whereas in breast carcinomas, nuclear FAK pY397 staining was detected in both tumor and associated blood vessel endothelial cells (13, 14).