MYC and cancer: It has been reported that many diseases, such as cancer [3], HIV [4], and diabetes [5], are closely related to G4s structures, which widely exist in variety of genes including bcl-2, c-myc, k-ras, the telomeres and c-kit G-quadruplex-forming sequences, and plays a crucial role in regulating the gene expression of different oncogenes [6–12].