CCNE1 and neoplasm: Cyclin E overexpression is present in several tumor types,[49,50] is upregulated by Myc,[51] and Cyclin E deregulation has been shown to be associated with acute onset of genomic instability.[50,52,53] Interestingly, overexpression of Cyclin E causes a diminishing of the number of MCM hexamers that load onto chromatin/DNA prior to S-phase[50] (Figure 3).