Our finding of Abi1 overexpression during the development of invasive carcinomas is comparable to findings made in ovarian cancer, where coexpression of the trimeric Abi1/SOS1/Eps8-complex is a prerequisite for Rac-dependent ovarial cancer cell motility upon lysophosphatidic acid (LPA)-stimulation [42]. Here, SOS1 is linked to ovarian carcinoma.