In epithelial cell-derived tumors, endosialin may promote tumor cell proliferation, adhesion and migration through cell-cell or cell-ECM interactions, while in mesenchymal cell-derived sarcomas, endosialin may promote tumor cell migration and invasion through intracellular pathways such as the FAK-paxillin pathway (summarized in Figure 1). This evidence concerns the gene PTK2 and neoplasm.