Although p21 promoter is a simple native promoter of a gene that is present in all human cells, it can be matched-up with these sophisticated synthetic promoters because it has similar characteristics: it is induced by hypoxia and irradiation, it has a high basal activity that is limited to tumor cells, and after the removal of a stimuli its activity in normal cell falls again to the basal level, but remains high in tumor cell. Here, CDKN1A is linked to neoplasm.