KLK3 and neoplasm: E1A is an essential gene in adenoviral replication and the first gene expressed upon oncolytic adenoviral infection.115 Many tumor-specific promoters that have been utilized to drive E1A expression are strategically applied to improve the specific antitumor activity of OAd, including the human telomerase reverse transcriptase promoter (hTERT), hypoxia-responsive promoter (HRE), prostate-specific antigen promoter (PSA), alpha-fetoprotein promoter (AFP), alpha-lactalbumin promoter (ALA) and mucin1 promoter (DF3/MUC1).116,117