Gene expression in human breast epithelial cells exposed to 60 Hz magneticfields

Epidemiology suggests a possible relationship between exposure to power fre quency magnetic fields (EMF) and breast cancer. One mechanism through which EMF could stimulate breast cancer induction is via altered expression of o ncogenes and/or tumor suppressor genes that regulate normal and neoplastic growth. To evaluate the hypothesis that EMF action in the breast is mediate d by alterations in gene expression, transcript levels of c-myc and a batte ry of other cancer-associated genes were quantitated in human breast epithe lial cells exposed to pure, linearly polarized 60 Hz EMF with low harmonic distortion. HBL-100 cells and normal (non-transformed) human mammary epithe lial cells were exposed to EMF flux densities of 0.1, 1.0 and 10.0 Gauss (G ) for periods ranging from 20 min to 24 h; concurrent sham controls were ex posed to ambient fields (<0.001 G) only, Gene expression was quantitated us ing ribonuclease protection assays. EMF exposure had no statistically signi ficant effect on basal levels of c-myc transcripts in either human breast c ell model, and had no effect on alterations in c-myc expression induced by 12-O-tetradecanoylphorbol-13-acetate. Transcript levels of c-erbB-2, p53, p 21, GADD45, bar, bcl-x, mcl-1, and c-fos were also unaffected by EMF exposu re. These results suggest that EMF is unlikely to influence breast cancer i nduction through a mechanism involving altered expression of these genes.