Two previously unrecognized genetic markers may predict whether breast cancer patients would benefit from chemotherapy followed by tamoxifen, according to preclinical research from Roswell Park Cancer Institute (RPCI), in collaboration with the cooperative research group SWOG and St. Jude Children's Research Hospital. The results of this research were presented at the American Association for Cancer Research (AACR) Annual Meeting 2016.
Victoria Larsen, a Howard University undergraduate doing research at Roswell Park, is the first author and Song Yao, PhD, Associate Professor of Oncology also in the Department of Cancer Prevention and Control at Roswell Park, is the senior author of "Germline genetic variants in GATA3 and breast cancer treatment outcomes in SWOG 8897 trial" (abstract 2032), was presented on Monday, April 18.
Patients' genetic makeup may influence how they respond to cancer treatment. In SWOG S8897, a multi-institutional clinical trial for breast cancer, a team of scientists examined 12 potential markers for an important breast cancer gene, GATA3, seeking to identify any associations with patients' survival. They broke the patients up into two distinct groups: those at high risk for cancer recurrence and those at low risk of recurrence. Within the high-risk group, one cohort of patients was treated with chemotherapy and the other with chemotherapy plus tamoxifen (n=441). Low-risk patients did not receive chemotherapy (n=799).
The team's analysis showed that two genetic markers in GATA3, rs3802604 and rs568727, accurately predicted which patients would benefit most from chemotherapy. Further investigation showed that the associations were particularly strong among patients who received tamoxifen following chemotherapy. The same two markers, however, were not predictive in the group of patients who did not receive chemotherapy, indicating that the prediction was specific to breast cancer chemotherapy.
"These findings suggest that GATA3 genetic markers may be useful in guiding the selection of optimal treatment regimens for breast cancer patients," says Dr. Yao. "Further studies should be conducted to validate the findings and broaden our understanding of the mechanisms behind different therapies."
This research is supported, in part, by the Susan G. Komen Breast Cancer Foundation.