PTK2 and gastric cancer: A recent study showed the lipid phosphate phosphatase-related protein type 4 (LPPR4) could upregulate integrin α subunits (including α1, α2, α5, α6, and α7), but not β subunits, expression via SP1 transcription factor; thus, activating the FAK/Src/AKT/MMP2 signaling pathway, which eventually promoted the PM in GC cells (Zang et al., 2020).