AFP and neoplasm: Based on mammalian synthetic biology, gene circuits have been creatively engineered to integrate tumor-specific promoters and microRNA (miRNA) inputs for the identification of specific cancer cells.118 Huang et al. engineered an innovative sensory switch circuit consisting of a Gal4VP16 activator gene driven by the AFP promoter and two mutually inhibiting repressor genes controlled by miR-142, miR-199a-3p, and miR-142.119 In this circuit setup, a high E1A level can be specifically achieved to trigger adenoviral replication in tumor cells.119