Groundbreaking Research Uncovers Why Bladder Cancers Resist Immunotherapy

Researchers at the Icahn School of Medicine at Mount Sinai and the Mount Sinai Tisch Cancer Center have identified a crucial biological pathway. This discovery helps explain why certain bladder cancers exhibit resistance to immunotherapy, offering new avenues for understanding and treating the disease.

The study, published in Cancer Discovery, establishes a pivotal connection between common inflammation markers in the blood and immune-suppressing cells found within tumors.

Unraveling the Mystery of Immunotherapy Resistance

The research reveals a previously unrecognized link between systemic inflammation in the blood and the suppression of the immune response inside tumors. This finding sheds light on why some patients do not respond to existing treatments.

High levels of C-reactive protein (CRP) and interleukin-6 (IL-6), both readily detectable inflammation markers in the blood, were strongly associated with poor patient outcomes. These elevated blood inflammation markers are directly linked to a specific type of immune cell within tumors.

This specific cell type is known as SPP1+ macrophages. These macrophages possess the critical ability to deactivate cancer-fighting T cells, thereby potentially hindering the effectiveness of immune checkpoint inhibitors, a cornerstone of modern immunotherapy.

In contrast to these suppressive cells, the team also identified CXCL9-marked macrophages. These macrophages contribute to T-cell activation and are associated with stronger, more effective immune responses against cancer.

Transforming Treatment Strategies

The implications of these findings are substantial for the future of cancer treatment, particularly for bladder cancer and other inflammation-driven cancers.

The findings suggest that routine blood tests for CRP and IL-6 could provide invaluable insights into the immune environment within a patient's tumor. This could potentially identify individuals less likely to respond to current immunotherapy approaches, allowing for more personalized treatment plans.

The study points to SPP1+ macrophages and IL-6-related signaling pathways as promising targets for future therapies.

Modulating or reprogramming these specific macrophages could significantly enhance immune activity and improve immunotherapy outcomes. Furthermore, the research provides additional support for ongoing and future clinical trials investigating drugs that target IL-6 signaling and associated inflammatory pathways in combination with immunotherapy.

The Research Team

The study was expertly led by Nina Bhardwaj, MD, PhD, Director of Immunotherapy; Matthew Galsky, MD, Director of Genitourinary Medical Oncology; and Diego Chowell, PhD, Assistant Professor of Artificial Intelligence and Human Health, and Immunology and Immunotherapy. Key co-authors included Michelle A. Tran, PhD, Byuri Angela Cho, PhD, Sudeh Izadmehr, PhD, and Seung-Keun Yoo, PhD.