ITGBL1 is known to promote cancer metastasis and invasion by the WNT/PCP, FAK/SRC, and TGF-β signaling pathways, yet our previous study suggested that ITGBL1 was a secreted protein and that it inhibited integrin activation (Berg et al. 1999; De Pascalis and Etienne-Manneville 2017; Gan et al. 2016; Li et al. 2015; Sun et al. 2016). This evidence concerns the gene PTK2 and cancer.