E2F1 and neoplasm: A recent study on the interbreeding of MMTV-PyMT mice with E2F1, E2F2, or E2F3 knockout mice showed that in addition to cell cycle control E2F targets a number of genes related to angiogenesis, extracellular matrix modification, proliferation and survival of tumor cells which was important for metastasis (Hollern et al., 2014[23]).