The aim of this study was to test whether exposure to microwaves activated the heat-shock factor (HSF), which is a necessary but not sufficient condition for the induction of the heat-shock response. The DNA-binding activity of HSF in hamster, mouse and human cells was determined after acute (5-60 minutes) or continuous (up to 7 days) exposures to FDMA (835.62 MHz) or CDMA (847.74 MHz) - modulated microwaves at low (0.6 W/kg) or high (5.0 W/kg) SARs. The DNA- binding activity of HSF was monitored using a gel shift assay.

Increasing the temperature of the assay by as little as 1°C for 15 minutes caused an increase of approximately 10% in the DNA-binding activity. When the temperature was rigorously controlled, there was no evidence of any increase in the activation of HSF as a result of exposure to the microwaves. The authors state: