Alpha-fetoprotein promoter (AFP promoter) (AFP promoter)

The Alpha-fetoprotein (AFP) promoter is a cis-acting DNA regulatory element that controls the transcription of the AFP gene, which is primarily expressed during fetal development in the liver and yolk sac (UniProt, 2024). In healthy adults, this promoter is transcriptionally silenced, but it becomes reactivated in approximately 60-80% of hepatocellular carcinoma (HCC) cases and certain germ cell tumors (Gao et al., 2011). This tumor-specific reactivation makes the AFP promoter a valuable tool in gene therapy for the transcriptional targeting of therapeutic agents. By placing “suicide genes” (such as herpes simplex virus thymidine kinase) or oncolytic viral genes under the control of the AFP promoter, researchers can ensure that these agents are expressed selectively within AFP-producing cancer cells (Sauer & Anderson, 2014). This approach aims to maximize the destruction of malignant tissue while minimizing damage to surrounding healthy liver cells that do not support AFP promoter activity. However, the clinical utility of this target is limited by the heterogeneity of AFP expression in HCC patients and the relatively low transcriptional activity of the promoter compared to strong viral promoters (NIH, 2023). Safety concerns also include the potential for off-target activation during periods of liver regeneration or in rare adult tissues where AFP might be transiently expressed.

Other names

AFP gene promoterAlpha-fetoprotein gene regulatory elementAFP regulatory sequenceAFP-specific promoter

The AFP promoter acts as a transcriptional switch that restricts the expression of downstream therapeutic genes (e.g., suicide genes or oncolytic factors) to cells that express the necessary transcription factors for AFP, specifically hepatocellular carcinoma cells.