APLP2 and cancer: Otherwise, the surface expression of HGprt enzyme was also observed in several somatic tissue cancers [133]–[139] while an important function of APP as a tumor growth factor in the pathogenesis of several somatic tissue cancers has been suggested and APP as well as APP-like protein-2 (APLP2) are deregulated in cancer cells and linked to increase tumor cell proliferation, migration, and invasion [140],[141].