Ehrlich tumor as model to study artificial hyperthyroidism influence on breast cancer.

Abstract

This study used Ehrlich solid tumor as an experimental model for breast cancer to investigate the effects of thyroid hormones and castration on tumor development in adult female mice. Artificial hyperthyroidism was induced in animals, and after a 30-day-treatment, they received subcutaneous injection of neoplastic cells between left plantar cushions. We measured the growth of tumor inoculated in the paws for 10 days at necropsy. Hyperthyroidism induction led to significantly increased tumor size in non-castrated animals, and alterations were less intense in association with artificial hyperthyroidism and castration (p<0.05). Histomorphologic and histomorphometric analyses and neoplastic cell characterization were carried out by measuring nuclear diameter, by evaluating AgNORs, by mitotic count, and by measuring cell proliferation using immunohistochemical marker CDC47. At the end of the experiment, we noted metabolism and a decrease in cell proliferation in groups having received l-thyroxine, which were more evident in the non-castrated group (p<0.001).