PTK2 and neoplasm: Maintains the self-renewal of mouse ES cells through Bmi-1 via α2β1 integrin and DDR1; promotes EMT; CD133+ glioblastoma CSCs are localized to type I collagen-rich perivascular niche; GBM cells cultured on type I collagen maintain stemness and tumorigenicity; increases expression of CD133 and Bmi1, EMT and clonogenicity in colorectal CSCs through α2β1 integrin; enhances tumor-initiating potential and self-renewal of ALDH+ pancreatic CSCs through β1integrin and FAK signaling.