Fibroids are the most common pelvic tumors and are sensitive to fluctuations in hormones. Alpha fetoprotein (AFP) has demonstrated anti-estrogenic properties. AFPep is an active site peptide that retains the properties of AFP. Here, we investigated the ability to grow human fibroid xenografts in a murine model and the effect of AFPep on the growth of fibroid tumors.METHODS:
After IRB approval, patients were identified and consent obtained. Pathology was confirmed by frozen section and the fibroid was implanted under the kidney capsule of ICR/SCID mice along with an estrogen implant. Survival surgery was completed to asses for growth. A second generation was completed followed by another fresh sample. After demonstrable growth, control mice were given normal saline injections and experimental group given AFPep injections for 10 days. Animals were sacrificed 1 hour following the last injection and samples were formalin fixed.RESULTS:
In the first generation of fibroid implantation, 60% of the fibroids demonstrated growth, with the greatest growth noted days 12–30. The second generation of fibroids showed accelerated growth. The percent difference in tumor volume after AFPep treatment was less in the treatment group (46% vs 95%) and one tumor showed 11% volume regression.CONCLUSION:
Fibroid xenografts demonstrate growth in a mouse model and the rate of growth is faster in second generation xenografts. Additionally, AFPep may display some inhibitory growth properties with a smaller difference in tumor volume in the treatment group. Histologically, the treatment group showed evidence of increased apoptosis, hyalinized fibrosis, and decreased cellularity.