Researchers have identified the histone H2AX as a potential biomarker for breast cancer — a determination that could also help predict how a patient will respond to radiation therapy.
The research team is presenting the findings of their research at the American Association for Cancer Research (AACR) Annual Meeting 2018.
Histones are a family of small proteins responsible for folding and packaging DNA into tightly packed strands.
The histone H2AX plays a central role in the repair of damaged DNA, and although this histone is often much more active in cancer cells than in normal cells, its role in breast cancer is not very clear.
Examining expression levels of H2AX in breast cancer tumor data from The Cancer Genome Atlas, a large National Institutes of Health database containing genetic information about tumor tissue from more than 11,000 patients, the Roswell Park team found that breast cancer patients whose tumors had high levels of H2AX had a significantly worse prognosis than those with low levels.
This finding was true for both overall survival and disease-free survival, or the length of time after treatment that the patient survives without any signs or symptoms of breast cancer.
“We knew that this histone played a large role in DNA repair, but here we found that H2AX is involved in several different pathways leading to the development of breast cancer,” says Dr. Eirko Katsuta, first author and postdoctoral Research Fellow in the Roswell Park Department of Breast Surgery. “The association between H2AX and a poor outcome was significant for all breast cancer patients, especially those with advanced disease.”
Remarkably, the team also found that tumours with high levels of H2AX were more sensitive to radiation than other tumours.
“Our findings suggest that H2AX could be used to identify breast cancer patients who have a poor prognosis but are more likely to respond well to radiation therapy, which could help personalize and improve treatment,” adds senior author Dr. KazuakiTakabe.
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