Tamoxifen (Soltamox/Nolvadex®; AstraZeneca), an antagonist of the estrogen receptor ? in ER?-positive breast cancer has been effective in most patients. The drug has been used for more than 40 years to treat breast cancers that are hormone-receptor positive. As an adjuvant therapy tamoxifen improves overall survival. Its widespread use is thought to have made a significant contribution to the reduction in breast cancer mortality seen over the last decade.  However, resistance to tamoxifen is a clinically significant problem.
So far, the mechanisms responsible for tamoxifen resistance remain elusive. Results from a study funded by the Dutch Cancer Society (KWF) published in Cancer Research, a journal of the American Association for Cancer Research discusses a new approach that has the potential to be used in the clinic to predict which patients with estrogen receptor-positive breast cancer will benefit from tamoxifen therapy after surgery. 
We have used a very innovative approach to identify genes that help foretell whether a patient will respond to tamoxifen, and we showed that this gene signature performed well in two large patient groups, explained René Bernards, PhD, professor and head of the Division of Molecular Carcinogenesis at the Netherlands Cancer Institute (NKI) in Amsterdam, The Netherlands.
Read the full article: Breast Cancer Treatment Response to Tamoxifen Predicted by Gene Signature. Onco'Zine - The International Oncology Network. July 17, 2014. http://adc.expert/1p10Zyu
 Ring A, Dowsett M. Mechanisms of tamoxifen resistance. Endocr Relat Cancer. 2004 Dec;11(4):643-58.
Oosterkamp HM, Hijmans EM, Brummelkamp TR, Canisius S, Wessels LF, Zwart W, Bernards R. USP9X Downregulation Renders Breast Cancer Cells Resistant to Tamoxifen. Cancer Res. 2014 Jul 15;74(14):3810-20. doi: 10.1158/0008-5472.CAN-13-1960.
A study published online in the August 2014 edition of the Annals of Surgical Oncology shows that BluePrint (Agendia Inc) proves to be superior to conventional subtyping for analyzing breast cancer before surgery. 
The study, which will also be published in the October print edition of the journal, is part of the ongoing Neoadjuvant Breast Registry Symphony Trial (NBRST, pronounced "N-breast").
These finding may eventually change the way physicians evaluate and treat breast cancer. The researchers concluded that the BluePrint genomic test provides more accurate information about the molecular subtype of a specific breast cancer, compared to the use of conventional immunohistochemistry (IHC)-fluorescence in situ hybridization (FISH) pathology tests.
To read the full article, go to Onco'Zine - The International Oncology Network (http://adc.expert/1t2kjJU)