PTK2 and neoplasm: A second study used an oral, small molecule focal adhesion kinase (FAK) inhibitor, FAKi (VS-4718), alone, and in combination with a blocking antibody to the checkpoint protein T cell immunoglobulin and ITIM domain (TIGIT), an inhibitory receptor expressed on lymphocytes that interacts with CD155 expressed on APC or tumor cells to down-regulate T cell and NK cell functions.