E2F1 and cancer: The review on the functions of ID1, BCL2L1, TPX2, HCK, PLAG2, POFUT1, DNMT3B, E2F1, and E2F6 in cancer reveals a plethora of pathways by which the higher expression of these genes, as a result of their increased copy number, affects the progression of cells through different stages of malignancy.