June 11, 2009

Protein may predict cancer drug resistance

Dutch and U.S. medical researchers have discovered a protein profile that may predict whether a breast cancer patient will be resistant to tamoxifen therapy.

Tamoxifen is a widely used and effective drug designed to treat breast cancer. But the scientists said resistance to tamoxifen is problematic in recurrent disease that affects 25 percent to 35 percent of patients because therapy resistant metastatic tumor cells are a major cause of death.

In the new study, Arzu Umar of the Erasmus University Medical Center and colleagues in the Netherlands and Washington examined thousands of tumor cells taken from 51 tamoxifen therapy-sensitive and therapy-resistant tumors. Using a combination of proteomic and mass-spectrometry approaches they identified a set of 100 proteins expressed at different abundance levels in the two tumor groups, highlighting a potential profile for tamoxifen resistance.

While further work with additional samples will be needed, the researchers said the profile could be clinically useful, especially considering their approach used minute amounts of tissue samples, making it applicable at even the earliest tumor stages.

The research is detailed in the journal Molecular and Cellular Proteomics.