Lymphoma development in mice chronically exposed to UMTS-modulated radiofrequency electromagnetic fields.

There are public concerns regarding possible carcinogenic or cancer-promoting effects of electromagnetic fields (EMFs) from mobile phones and base stations. The objective of the present study was to investigate whether chronic exposure to EMFs of the UMTS (Universal Mobile Telecommunication System) influences the development of lymphoma in a lymphoma animal model, the AKR/J mouse. Unrestrained mice were chronically sham-exposed (n = 160) or exposed (n = 160) in identical exposure systems (radial waveguides) to a generic UMTS test signal (24 h per day, 7 days per week, 0.4 W/kg SAR). Additionally, 30 animals were kept as cage controls. Animals were checked visually each day and were weighed and palpated weekly to detect swollen lymph nodes. Starting at the age of 6 months, blood samples were taken from the tail every 2 weeks to perform differential leukocyte counts and to measure the hematocrit. Visibly diseased animals or those older than 43 weeks were killed humanely, and tissue slices were examined for metastatic infiltrations and lymphoma type. The study was performed in a blinded way. Cage control animals had a significantly lower growth rate than those kept in the radial waveguides. The number of ill animals, the mean survival time, and the severity code of the disease did not differ between the experimental groups. Therefore, the data show no negative effects from exposure and corroborate earlier findings in AKR/J mice exposed to GSM EMF (Sommer et al., BMC Cancer 4, 77-90, 2004).