PTK2 and gastric cancer: A recent study in gastric cancer showed that the extracellular matrix protein 1 directly interacts with integrin α6β4 and enhances Hif-1α promoter activity to regulate glucose metabolism through the FAK/Sox2 pathway [29], indicating that the regulation of Hif-1α by integrin α6β4-signaling is at multiple levels, and is not limited to TNBC.