E2F1 and cancer: However, many studies have shown that polyubiquitin-C interacts with various cancer-associated effector molecules, including cdk1 [27], E2F1 [28], epidermal growth factor receptor (EGFR) [29], HDAC3 [27], HIF1A [30], Mdm2 [31], NOTCH1 [32], and p53 [29].