DETROIT, April 30 Breast-cancer cells that express estrogen receptor can be treated with tamoxifen only as long as they remain sensitive to the drug, says a U.S. study.Resistance to tamoxifen is a common problem in breast-cancer treatment, but researchers are identifying the factors that influence sensitivity versus resistance, according to studies directed by Dr. Malathy P.V. Shekhar of Karmanos Cancer Institute and Wayne State University School of Medicine in Detroit.When tamoxifen-sensitive, premalignant breast-cancer cells were cultured with fibroblasts -- a type of cell that is key to wound healing -- derived from estrogen receptor-negative tumors, breast-cancer cells became less sensitive to tamoxifen.The data demonstrate that fibroblasts influence the sensitivity of breast-cancer cells to tamoxifen, according to the study published in The American Journal of Pathology.Copyright 2007 by UPI
