STAT3 and cancer: It has been suggested that, compared to the genotype containing two copies, the genotype involving three copies of the CCGCC motif might enhance the binding affinity to E2F-1 and, as a result, promote cancer progression by activating transcription of multiple oncogenes such as myc gene (myc), signal transducer and activator of transcription 3 (STAT3) and β-catenin (β-cat)14,20,21.