exposure to electromagnetic fields may induce tamoxifen resistance
 

only in the petri dish and not on her2+ breast cancer cell lines specifically but something to think about(when wondering why one treatment works on one person and not another)

: Bioelectromagnetics. 2007 Nov 20; [Epub ahead of print] Links
Electromagnetic fields alter the expression of estrogen receptor cofactors in breast cancer cells.

Girgert R, Gründker C, Emons G, Hanf V.
Department of Gynecology and Obstetrics, University of Göttingen, Göttingen, Germany.
Breast cancer is the most common malignancy of women in Western societies. The increasing exposure to electromagnetic fields has been suspected to contribute to the rising incidence of breast cancer in industrialized countries. The majority of breast tumors is treated with the partial antiestrogen tamoxifen. Most tumors become resistant to tamoxifen in the course of treatment resulting in treatment failure. Electromagnetic fields reduce the efficacy of tamoxifen similar to tamoxifen resistance. In this study we investigated the mechanism by which electromagnetic fields influence the sensitivity to tamoxifen. In cells exposed to 1.2 microT of a 50 Hz electromagnetic field gene expression of cofactors of the estrogen receptors was compared to sham exposed cells. Using a gene array technology several cofactors were found to be differentially expressed. The expression of the coactivators, SRC-1 and AIB1, and of two corepressors, N-Cor and SMRT, was quantified by RT-PCR. Both coactivators were expressed more strongly in the exposed cells while the expression of two corepressors decreased. The RNA analysis was confirmed by Western blots. The contradirectional changes in gene expression of coactivators and corepressors by electromagnetic fields results in a lower sensitivity to tamoxifen. Electromagnetic fields may contribute to the induction of tamoxifen resistance in vivo. Bioelectromagnetics, 2007. (c) 2007 Wiley-Liss, Inc.
PMID: 18027843 [PubMed - as supplied by publisher]