GAB1 and neoplasm: Importantly, SUMO1 modification at K590 of hShp2 increased Shp2 binding to the Gab1, although having no effect on its catalytic activity, promoting EGF-stimulated ERK activation and increasing HCC cell anchorage-independent growth and xenograft tumor growth, which reveals a new mechanism for the regulation of Shp2 function in Ras/ERK signaling pathway (Figure 7).