Systemic changes in B cells induced by tumors can predict the likelihood of response to standard-of-care chemotherapy and immunotherapy in patients with triple-negative breast cancer. The study, published in Nature Cell Biology, reveals two distinct patterns of B cell abnormalities in patient blood and bone marrow that could serve as blood biomarkers.
Identifying B Cell Subgroups
Researchers, led by Dr. Xiang H.-F. Zhang at Baylor College of Medicine, examined changes in B cells from patient blood samples and identified three subgroups: TiBA-0, TiBA-1, and TiBA-2. The TiBA-0 group showed no changes to B cells, while TiBA-1 had a reduced number of B cells, and TiBA-2 had an increased number of immature B cells.
"Even with significant advances in immunotherapy, only about 15 to 20% of patients with triple negative breast cancer will benefit from this treatment," said Dr. Zhang. "My lab is trying to understand why some cancers do not respond to treatment by examining the crosstalk between the tumor and the body. Many systemic changes arise because of how the body responds to the cancer."
Impact on Treatment Response
The study found that B cell changes in both TiBA-1 and TiBA-2 types lead to an immunosuppressive effect and poorer response to treatment. In a cohort of 35 patients, 78.6% of TiBA-0 patients had a complete response to treatment with chemotherapy and immunotherapy, while only 33.3% of TiBA-1 and TiBA-2 patients had a complete response.
Systemic Biomarkers
"These immune cell changes are not just happening locally inside the tumor. We see them systemically across the entire body, which means that we can identify these immune cell biomarkers with a simple blood draw," said Zhang. "In the future, we may be able to stratify patients based on these biomarkers and determine which patients are less likely to respond to standard therapies and require additional treatment."
Future Directions
Dr. Zhang's team plans to collaborate with other researchers to study these blood biomarkers in a larger patient group over multiple time points during treatment. The goal is to better understand how immune cells change over time and to explore ways to reverse tumor-induced changes in bone marrow to restore normal immune cell production.
