PTK2 and neoplasm: While invasion and metastasis of gastric cancer is significantly increased upon upregulation of biglycan that activates the focal adhesion kinase (FAK) signaling pathway (inducing phosphorylation of FAK and Paxillin) [114], tumor angiogenesis has been linked to biglycan-mediated regulation of vascular endothelial growth factor (VEGF), correlated with activation of the ERK signaling pathway in colon cancer [115].