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2008
Journal Article
Titel
Tumor promotion by long-term UMTS electromagnetic field exposure in B6C3F1 mice prenatally treated with ENU
Titel Supplements
Abstract
Abstract
Objective: To evaluate possible influences on tumor development in freely moving mice following exposure to a generic UMTS (universal mobile telecommunications system) test signal for 20 h/day on 7 days/week, starting as fetal exposure. Methods: The experiment was carried out as a one-generation study with prenatal exposure, using two EMF treatment groups ["UMTS high-dose group" + "UMTS mid-dose group" with additional ethylnitrosourea (ENU) treatment], and a sham-exposed control group in the EMF exposure device, in addition to an cage control group and a positive (ENU-treated) control group. Starting on day 6 of pregnancy maternal mice were UMTS-exposed, while lifetime exposure (up to 24 months) of the F1 descendants started on the day of birth. Maternal ethylnitrosourea administration (40mgENU/kg b.w.) was carried out on day 14 of pregnancy. The exposure was performed in a three-level exposure unit [sham, medium-dose (4.8W/m2), high-dose (48W/m2)] consisting of three stacked radial waveguides (one level for each dose group) and housing up to 60 female B6C3F1 mice (3 per cage) per level. Histopathological examinationwas limited to neoplasms and pre-neoplastic lesions of the brain, lungs, liver, spleen, kidneys, mesenterial lymph nodes, and gross lesions. Results/conclusion: The cage control group,shamexposure group and UMTS high-dose group revealed comparable tumor incidences in the target organs. The UMTS high-dose group, in contrast, showed a significantly increased number of pre-neoplastic liver foci as compared to the sham control and cage control groups. Analysis of the neoplastic and pre-neoplastic findings in the two ENU groups revealed some remarkable findings: A comparison of neoplastic lesions revealed an increased liver tumor rate and a significantly increased lung tumor incidence in the ENU/UMTS group as compared to the ENU control group. Incidences of hepatocellular adenoma(s) and bronchiolo-alveolar carcinoma(s) were significantly increased in the ENU groups after lifetime UMTS exposure. A Present address: Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen, Germany. With respect to bronchiolo-alveolar carcinoma(s) and hepatocellular adenoma(s), tumor multiplicity was significantly increased in the ENU/UMTS group as compared to the ENU control group. The incidence of metastasizing lung carcinoma(s) in the two ENU groups was doubled by the long-term UMTS exposure of the mice. In addition, the incidence of pre-neoplastic hepatocellular foci also increased significantly in the ENU/UMTS group as compared to the ENU control group. In conclusion, the study revealed distinct tumor-promoting effects of chronic UMTS exposure in this ENU mouse model. It currently remains unclear, however, to what extent these limited results (promotion of ENU-induced tumorigenesis by long-termUMTSexposure) are predictive of human carcinogenesis. Support by Compagnia di San Paolo, Torino, Italy, is gratefully acknowledged.