Background: The aim of this study was to evaluate the effect of tamoxifen on angiogenesis induced in rabbit cornea by breast carcinoma from post-menopausal women.
Methods: Thirteen post-menopausal women with operable, estrogen receptor-positive breast carcinomas, treated with 20 mg of tamoxifen daily for 30 days prior to undergoing definitive surgery, participated in this study. Twenty-six virgin female New Zealand white rabbits, 3-4 months old, weighing approximately 2.5 kg each, were divided into two groups of 13 animals and received corneal implants of tumor either pre- or post-tamoxifen treatment. After 10 days, the animals were sacrificed, the region of the cornea between the tumor implant and the limbus was removed and quantification of angiogenesis was carried out by evaluating the entire hematoxylin-eosin stained slide, using a 10x objective lens (100x magnification). Student t-test was used in the statistical analysis of the data and statistical significance was established at P < 0.05.
Results: Mean microvessel count was 106.8 +/- 5.9 pre-tamoxifen treatment and 54 +/- 5.6 post-treatment. According to Student t-test, there was a significant reduction in mean microvessel density following treatment with tamoxifen (P < 0.001).
Conclusions: Rabbit cornea proved to be an interesting experimental model for the quantification of angiogenesis. Tamoxifen, when administered for 30 days to post-menopausal women with breast cancer, significantly inhibited angiogenesis induced by tumor fragments in rabbit cornea.