Increased transglutaminase 2 and GLUT-1 expression in breast tumors not susceptible to chemoprevention with antioxidants.

GOALS Expression of GLUT-1 and transglutaminase 2 is increased in aggressive breast cancer, whereas claudin-1, which is expressed in normal tissues, is absent in such tumors. This experimental study was undertaken to establish the aggressiveness and prognosis of DMBA-induced mammary tumors in female Wistar rats based on the assessment of these markers. MATERIALS AND METHODS The rats were divided into two groups, a control group (n = 70) and a chemoprevention group (n = 70). Breast tumors were induced in both groups by administration of 7,12-dimethylbenz[a] anthracene (DMBA). The chemoprevention group also received alpha-tocopherol and a solution of micronutrients containing ascorbic acid and selenium. Neoplastic lesions of both groups were randomly selected for immunohistochemical assessment of the expression of GLUT-1, transglutaminase 2 and claudin-1. RESULTS A higher proportion of mammary tumors expressed GLUT-1 and transglutaminase 2 in the chemoprevention group. Claudin-1 expression was absent in all tumors of both groups. CONCLUSIONS These results are suggestive of increased aggressiveness of tumors not susceptible to chemoprevention by the agents used in this study.