Study Finds Way to Reverse Tamoxifen Resistance in Breast Cancer

Researchers found combined tamoxifen with dasatinib reversed chemotherapy resistance caused by fibroblasts in the surrounding tissue.

For most women with estrogen-receptor-positive breast cancer, the drug tamoxifen reduces tumors. However, in an uncomfortably large minority of cases--about 35%--breast cancer tumors either fail to respond to tamoxifen or build up an immunity to the drug. Now, researchers at the Kimmel Cancer Center at Thomas Jefferson University in Philadelphia have discovered a way to reverse this resistance to tamoxifen.

Researchers combined tamoxifen with dasatinib and found that it reversed chemotherapy resistance caused by fibroblasts in the surrounding tissue. The combination of drugs had an "antioxidant effect" in these types of cancer cells, Jefferson's Michael P. Lisanti, said in a release.

This combination of drugs killed 80% of the breast cancer cells, two to three t