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Researchers at the University of Alberta (Edmonton, AB, Canada) and the University of Lethbridge (Lethbridge, AB, Canada) have found that short but powerful bursts of terahertz radiation may both cause DNA damage and increase the production of proteins that help the body fight cancer.

Terahertz photons are not energetic enough to break the chemical bonds that bind DNA together in the nucleus of cells. But recent theoretical studies suggest that intense terahertz pulses of picosecond duration may directly affect DNA by amplifying natural vibrations of the hydrogen bonds that bind together the two strands of DNA. As a result, bubbles or openings in DNA strands can form.

This flags DNA double-strand break site and attracts cellular DNA repair machinery to it.

They observed terahertz pulse-induced increases in the levels of multiple tumor suppressor and cell-cycle regulatory proteins that facilitate DNA repair. This may suggest that DNA damage in human skin arising from intense picosecond terahertz pulse exposure could be quickly and efficiently repaired, therefore minimizing the risk of carcinogenesis.

The researchers confirmed that these cellular repair mechanisms were taking place by detecting an elevated presence of multiple proteins that play vital roles in DNA repair, including protein p53 (often called the guardian of the genome; p21, which works to stop cell division to allow time for repair; protein Ku70, which helps reconnect the broken DNA strands; and several other important cell proteins with known tumor-suppressor roles.

These observations indicate that exposure to intense terahertz pulses activates cellular mechanisms that repair DNA damage.