Animals were exposed to UMTS electromagnetic fields with different intensities (4.8 and 48 W/m²) and the low-dose group (4.8 W/m²) was additionally subjected to prenatal ethylnitrosourea treatment (40 mg ENU/kg body weight).
In total, five treatment groups were used: Two exposure groups, sham exposure group, cage control group and positive control group (ENU treatment only). Exposure and sham exposure of the maternal mice started on day 6 post conception, while the maternal ENU treatment was carried out on day 14 post conception. Each treatment group consisted originally of up to 20 maternal mice and their litters. After the first week of lifetime, litter standardisation was performed and afterwards three female offspring per cage and their mothers were maintained up to the weaning time point. After weaning, maternal mice were removed from the cages and the study was conducted using the three remaining female offspring (thus about 60 mice per group).
Different pre-studies were also performed (e.g. concerning thermoregulation or ENU mortality of a different mouse strain).
Exposure duration: continuous for 20 hr/day, 7 days/week for up to 24 months
animals were treated in five groups: i) cage control - no treatment ii) ENU control 40 mg ENU per kg body weight iii) sham exposure iv) UMTS exposure to 4.8 W/m² + 40 mg ENU per kg body weight v) UMTS exposure to 48 W/m²
|Exposure duration||continuous for 20 hr/day, 7 days/week for up to 24 months|
|power density||4.8 W/m²||average over time||-||-||deck with low exposure|
|power density||48 W/m²||average over time||-||-||deck with high exposure|
|SAR||0.62 W/kg||average over mass||calculated||whole body||3 pups (3 g, together with the dam)|
|SAR||1.19 W/kg||average over mass||calculated||whole body||3 old females (55 g)|
|SAR||3.84 W/kg||average over mass||calculated||whole body||1 mature female (30 g)|
|SAR||4.48 W/kg||average over mass||calculated||whole body||1 mature female (30 g, together with 3 pups)|
|SAR||5.76 W/kg||average over mass||calculated||whole body||3 young females (12.5 g)|
The high-level UMTS exposure (48 W/m²), the sham exposure, and the cage control groups showed comparable tumour incidences in the organs. In contrast, the ENU-treated and UMTS-co-exposed (at 4.8 W/m²) animals displayed an enhanced lung tumour rate and an increased incidence of lung carcinomas as compared to the controls treated with ENU only. Furthermore, tumour multiplicity of the lung carcinomas was increased and the number of metastasising lung tumours was doubled in the ENU/UMTS co-exposure group as compared to the ENU control group.
The authors conclude that this pilot study indicates a cocarcinogenic effect of lifelong UMTS exposure (4.8 W/m²) in female B6C3F1 offspring subjected to pretreatment with ethylnitrosourea.