Chemoprevention and Mammary Neoplastic Aggressiveness – Experimental Study

Introduction: Some studies have shown that an increase in the expression of GLUT‐1 and Transglutaminase‐II is seen in aggressive mammary tumours, whereas the marking with Claudin‐1, expressed in normal tissues, is absent in such tumours. The purpose of this experimental study is to establish the aggressiveness and, therefore, the prognostic of DMBA‐induced mammary tumours in female Wistar rats. Materials and methods: The animals used in the experiment were divided into two groups: a control group (n=70), and the chemoprevention group (n=70). In bowth groups the neoplastic lesions were induced by the administration of 7,12‐Dimethylbenz[a]anthracene (DMBA). The chemoprevention group was also submitted to the administration of a solution of micronutrients, containing ascorbic acid and selenium from the day of the administration of DMBA until the sacrifice and one administration of alfa‐tocopherol after the administration of the carcinogen. The neoplastic lesions of both groups were selected randomly for immunohistochemistry for the evaluation of expression of GLUT‐1, Transglutaminase II and Claudin‐1. Results: In this study, by comparing the two experimental groups, we have observed a higher proportion of mammary tumours expression GLUT‐1 and Transglutaminase II in the chemoprevention group. On the other hand, Claudin‐1 was absent in all of the tumours of both groups. Conclusion: These results suggest the greater aggressiveness of tumours not susceptive to chemoprevention by the used agents.