A University of Medicine and Dentistry of New Jersey (UMDNJ)-New Jersey Medical School research team reports that mesenchymal stem cells in bone marrow may protect breast cancer cells that have metastasized to the marrow. Without this protection, anti-tumor immune responses normally would destroy them.
“Our findings show that regulatory T cells may be providing a facilitative environment in which breast cancer cells can survive and possibly resurge after years of disease-free survival,” explained Shyam Patel, an M.D./Ph.D. student at the University's New Jersey Medical School and the Graduate School of Biomedical Sciences.
Among the team’s research goals are to identify reasons for resistance to chemotherapy and radiation in breast cancer patients and to understand why breast cancer cells remain dormant in bone marrow for years. One idea the group developed is that cancer may have a stem cell basis.
“This study explains why breast cancer survives in the bone marrow of patients, even if the subject has a competent immune system,” Pranela Rameshwar, Ph.D. (pictured), professor in the Department of Medicine at the UMDNJ-New Jersey Medical School.
“If they are protected in bone marrow, the cancer cells will have an advantage to integrate within the microenvironment and adapt dormancy,” Rameshwar said. “These cells are likely to evade treatment since the location will be in a region that limits the dose of anti-cancer agents.”
The research team’s next step is to study the various subsets of breast cancer cells and the specific immune responses, since this may help determine which course of treatment is most beneficial and predict the patient’s outcome following treatment, Rameshwar said.
Illustration: University of Medicine & Dentistry of New Jersey.
University of Medicine & Dentistry of New Jersey News Release (04/30/10)
Abstract (The Journal of Immunology; 184, 5885-5894 (04/09/10))