Could a Growth Inhibitory Factor, Present Only during Pregnancy, be Made Available to Treat Cancer in Adults? A Commentary

Human alpha-fetoprotein (AFP) is well-known as the “gold standard” biomarker for liver and germ cell tumors. It has also been utilized as a pregnancy screening analyte for neural tube defects as well as Down syndrome, when combined with other gestational-age dependent biomarkers. However, a lesser known and recognized property of AFP is its role in the maintenance and monitoring of fetal growth during ontogenetic development in man. Although a major function of AFP during pregnancy involves the serum transport of estrogens, fatty acids, retinoid, and other compounds, the positive and negative regulation of fetal growth is a vital additional function of AFP. Human AFP largely functions as a growth promoting agent; however, the fetal protein is able to temporarily convert to a growth inhibitory factor in stress and shock environments in the fetal milieu. The development of a transient form of AFP or its derived peptides could be harnessed for use as an adjunct therapeutic agent to treat cancer in adults.