[Jackie07]

My tumor was only 5% ER positive and my oncologist put me on Tamoxifen. I've seen research abstracts talking about new trials for patients who are ER- to receive Tamoxifen.

Below is a recent abstract on the subject:

Int J Dev Biol. 2011;55(7-9):703-12.
Four decades of discovery in breast cancer research and treatment--an interview with V. Craig Jordan. Interview by Marc Poirot.

Jordan VC.
Source

INSERM UMR 1037, University of Toulouse III, Cancer Research Center of Toulouse, Institut Claudius Regaud, 20 rue du pont Saint Pierre, Toulouse Cedex, France.

Abstract

V. Craig Jordan is a pioneer in the molecular pharmacology and therapeutics of breast cancer. As a teenager, he wanted to develop drugs to treat cancer, but at the time in the 1960s, this was unfashionable. Nevertheless, he saw an opportunity and through his mentors, trained himself to re-invent a failed "morning-after pill" to become tamoxifen, the gold standard for the treatment and prevention of breast cancer. It is estimated that at least a million women worldwide are alive today because of the clinical application of Jordan's laboratory research. Throughout his career, he has always looked at "the good, the bad and the ugly" of tamoxifen. He was the first to raise concerns about the possibility of tamoxifen increasing endometrial cancer. He described selective estrogen receptor modulation (SERM) and he was the first to describe both the bone protective effects and the breast chemopreventive effects of raloxifene. Raloxifene did not increase endometrial cancer and is now used to prevent breast cancer and osteoporosis.The scientific strategy he introduced of using long term therapy for treatment and prevention caused him to study acquired drug resistance to SERMs. He made the paradoxical discovery that physiological estrogen can be used to treat and to prevent breast cancer once exhaustive anti-hormone resistance develops. His philosophy for his four decades of discovery has been to use the conversation between the laboratory and the clinic to improve women's health.