Biostimulation of human caecinoma cells with the argon laser: A previously unreported potential iatrogenic effect of lasers

Abstract

The human squamous carcinoma cell line Ps was subjected to treatment with a single mode argon laser at 514.5 nm. The temperature and energy levels delivered to the target cells were determined by a reproducible method of dosimetry. At energy levels between 860 to 990 J/cm 2 and a corresponding temperature of 39±1 °C, a significant delayed stimulation in DNA synthesis was noted after 24 hours, but the cells remained viable. However, at energy levels and temperatures higher or equal to 1100 J/cm 2 (41 °C), an immediate suppression of DNA synthesis was accompanied by nonviability of the Ps carcinoma cells. These results indicate that the argon laser has potential for selective biostimulation on carcinoma cell duplication at the specific “non‐thermal” range of 39±1 °C. Similar effects were not observed when the Ps carcinoma cells were heated to this same temperature using a standard heat bath. This phenomenon appears to represent a previously undescribed potential iatrogenic effect of the monochromatic laser beam in the treatment of cancer.