PTK2 and neoplasm: Our data are in line with the functions of other semaphorins which act through Rho GTPases, FAK, and Src kinase family members in regulating cell spreading during neurite outgrowth, tumor progression, and vascular barrier integrity (Barberis et al, 2005; Franco & Tamagnone, 2008; Shimizu et al, 2008; Le Guelte et al, 2012).