SP1 and cancer: The new plasmid (pMP) was constructed and MP was only expressed specifically in cancer cells, which could provide the required transcription factors (including c-Myc, SP1, human papillomavirus type 16 E6, and so on) and chromatin environment for the hTERT promoter46, 47, 48, 49, 50; as we observed the efficient expression of MP driven by the hTERT promoter in cancer cells in a cell transfection assay with F-LP/pMP in vitro.