The presence of a protein called GRB-7 is an indicator of poor breast cancer prognosis especially in aggressive forms of the condition, researchers at Oregon Health and Science University Cancer Institute have discovered.
According to principal investigator Shiuh-Wen Luoh, M.D., Ph.D., assistant professor of medicine (hematology/medical oncology) in the OHSU School of Medicine, presence of GRB-7, or growth factor receptor-bound protein-7, is strongly related to the growth and spread of the cancer.
Located close to HER-2/Neu gene that regulates breast cancer growth, GRB-7 protein has previously been shown to be important to cell communication in the spread of cancer.
It was found that levels of GRB-7 protein and HER-2/Neu increased at the same time and often, breast tumors overexpressed one but not the other protein.
"It is surprising that we found discordance in the overexpression of these genes because they are so close together," said Luoh.
563 primary breast cancer specimens collected during a 20-year period for the OHSU Cancer Institute Breast Tumor and Clinical Data Repository, were analysed for the study. It was shown that one in six breast tumors have high GRB-7 protein, and these tumors have more aggressive, fast-growing and fast-spreading characteristics unlike HER-2/Neu positive tumors.
"We think that identifying the individual contribution of the GRB-7 and its interaction with HER-2/ Neu gene may eventually help physicians better predict the clinical course of breast cancer in their patients. Also, new treatments might be designed to interfere with the actions of GRB-7 that can stop the growth and spread of a portion of breast cancer tumors," said Luoh.
The researchers speculate that GRB-7 might influence a tumor's response to existing treatment and the findings of the study can lead to a clinical test for GRB-7 and better treatment for patients with GRB-7 positive breast tumors.
The research will be presented at the annual American Association for Cancer Research meeting in San Diego.