Estrogen (ER)-negative breast cancer patients have more hope with more drug-treatment options available, states a study done at Creighton University.
The study is reported in the October 11 online version of the journal Oncogene.
"The prevailing thought is that estrogen signaling is not involved in the development or progression of ER-negative breast cancer and, as a result, hormonal treatments that may follow surgery or radiation are not an effective option for this type of cancer. However, our study suggests that estrogen-signaling is involved, and novel hormonal treatments may help a number of women with ER-negative cancer," said Zhao-Yi "Charlie" Wang, Ph.D., the articles''s principal author.
Wang, a professor of cancer research in the Department of Medical Microbiology and Immunology and the Department of Pathology at Creighton University School of Medicine, described the findings as very promising. He added that more research is needed.
"About 25-30 percent of all breast cancers are ER-negative," he noted. "ER-negative breast cancers, especially triple-negative ones, are usually very aggressive; young African American women are at particular risk. This is potentially very promising news for these women."
For the study, researchers looked at specimens from 12 human cases of triple-negative breast cancer, known as such because this form of ER-negative cancer lacks estrogen and progesterone receptors and does not express the protein HER2 (human epidermal growth factor receptor 2).
Of the 12 cases, ER-a36, a novel estrogen receptor variant that Wang''s laboratory identified and cloned in 2006 (U.S. Patent No. 7,745,230), was highly expressed in 10.
The researchers then investigated the mechanism by which non-genomic estrogen signaling, brought about by ER-a36, contributes to the malignant growth of triple-negative breast cancer cells. Their findings indicate that ER-a36 may play an important role as a diagnostic and prognostic marker to assist in the individualization of breast cancer therapy as well as in the development of new therapeutic approaches.
In addition to Wang, Zoran Gatalic, M.D., Creighton professor of pathology; Semir Vranic, M.D., a former Creighton research fellow; and Ling Ding, M.D., of Zhejiang University School of Medicine in China, were among the co-authors of the article.
The research was supported by the National Institutes of Health and the Nebraska Tobacco Settlement Biomedical Research Program (LB-595 and LB-692).