PTK2 and neoplasm: The IC50 of VS-4718 in pancreatic cancer cell lines ranged from 1.23 to 3.99 μM, whereby the response between the three cell lines to VS-4718 varied, which is in agreement with the findings of Shapiro et al., who reported fluctuations in IC50 of VS-4718 in different cell lines, having attributed it to the difference in Merlin’s expression which regulates FAK function [44], and also with findings in pediatric tumor cell lines [45].