At the heart of this research lies the cysteinyl leukotriene receptor 1 (CysLTR1), a molecule historically associated with asthma pathophysiology and inflammatory responses. For decades, drugs such as montelukast have targeted CysLTR1 to mitigate asthma symptoms effectively. However, Northwestern scientists have unveiled a sinister role for this receptor in cancer biology, demonstrating that various tumors exploit CysLTR1 to suppress immune defense and promote their own growth. This revelation provides a compelling rationale for redirecting anti-asthma therapies toward oncology.

Through meticulous experimentation involving murine models and human tissues, the research team discovered that tumors can orchestrate an increase in neutrophils, a subtype of white blood cells normally tasked with combating infections. Instead of attacking cancer cells, these neutrophils are reprogrammed by tumors into immunosuppressive agents, creating a microenvironment that shields malignancies from immunotherapeutic interventions. The scientists pinpointed CysLTR1 as the molecular switch orchestrating this neutrophil-mediated immunosuppression.

Leveraging both genetic ablation techniques and pharmacological inhibition with montelukast, the researchers demonstrated a remarkable reduction in tumor growth across multiple cancer types, including notoriously treatment-resistant triple-negative breast cancer, melanoma, ovarian, colon, and prostate cancers. Crucially, these interventions not only decelerated tumor progression but also restored the efficacy of immune checkpoint therapies, even in cases where tumors had developed resistance.

The capacity to reprogram, rather than merely deplete, neutrophils represents a conceptual leap in cancer immunology. “By inhibiting CysLTR1, we encourage the transformation of neutrophils from tumor-promoting accomplices to tumor-attacking allies,” explains Dr. Bin Zhang, the study’s senior author and Johanna Dobe Professor of Cancer Immunology at Northwestern University Feinberg School of Medicine. This paradigm shift suggests that the innate immune system’s plasticity can be harnessed to overcome profound immunotherapy resistance commonly observed in aggressive cancers.

Augmenting their experimental data, the scientists conducted comprehensive analyses of human cancer samples and large-scale patient datasets. They identified a clear correlation between elevated CysLTR1 activity and poor clinical outcomes, including reduced survival rates and diminished responses to immunotherapy across diverse malignancies. This association underscores the clinical relevance of targeting CysLTR1 in the fight against cancer.

Given the pre-existing FDA approval of montelukast for asthma and allergies, these findings open the door to rapid translational applications. The drug’s safety profile and widespread availability significantly lower the barriers to clinical trials investigating its efficacy as an adjunct to current cancer therapies. The prospect of repurposing a familiar medication to improve outcomes for patients with intractable cancers is both promising and practical.

Future directions involve meticulous validation of this mechanism in human clinical trials, stratifying patients most likely to benefit from CysLTR1 inhibition, and optimizing combinatory regimens integrating montelukast with cutting-edge immunotherapeutic agents. The orchestration of these clinical investigations could herald a new era in cancer treatment, characterized by the strategic manipulation of the tumor microenvironment.

This study exemplifies the potential of re-examining well-characterized drugs through the lens of tumor immunology, unearthing novel therapeutic avenues from existing pharmacopoeia. It also highlights the importance of understanding the dualistic nature of immune cells within pathological contexts, where the same cell types can be co-opted to either harm or heal depending on molecular cues.

The insights from this work lay a concrete foundation for developing innovative treatments targeting myelopoiesis—the formation of myeloid cells like neutrophils—in cancer. By designing interventions that recalibrate immune cell function rather than indiscriminately eliminating cells, researchers move toward precision immunomodulation that could yield more durable and effective responses.

In sum, the findings represent a monumental stride in overcoming immune checkpoint therapy resistance, a formidable barrier in oncology. The ability to switch off the tumor’s immunosuppressive machinery and restore immune competence through a known, well-tolerated drug signals a beacon of hope for patients battling some of the deadliest cancers today.

Subject of Research: Role of cysteinyl leukotriene receptor 1 (CysLTR1) in tumor-induced immunosuppression and its blockade using montelukast to reprogram immune cells and overcome immune checkpoint therapy resistance.

Article Title: Targeting cysteinyl leukotriene receptor 1 reprograms tumor-promoting myelopoiesis and overcomes immune checkpoint therapy resistance.

News Publication Date: 19-May-2026

Web References: 10.1038/s43018-026-01174-7

Image Credits: Northwestern University / Senior study author Dr. Bin Zhang

Keywords: Cancer, Immunotherapy, Tumor Immunology, Neutrophils, Myelopoiesis, Montelukast, CysLTR1, Asthma Drug, Triple-negative Breast Cancer, Immune Checkpoint Therapy Resistance, Tumor Microenvironment, Immune Cell Reprogramming

At the heart of this elusive mechanism lies a sugar molecule known as sialic acid. Under physiological conditions, normal cells decorate their surfaces with sialic acid residues to convey a protective “don’t attack” message to immune cells. This molecular signal ensures immune tolerance and prevents unwarranted inflammation or autoimmunity. However, the Northwestern team found that pancreatic cancer cells exploit this natural safety feature by amplifying sialic acid presentation on a key surface protein, integrin α3β1. This glycosylation event transforms the integrin into a deceptive agent that binds immune inhibitory receptors, effectively sending a “stand down” message to immune cells.

This false signaling is mediated by a receptor expressed on immune cells called Siglec-10, a member of the sialic acid-binding immunoglobulin-like lectins family. When Siglec-10 interacts with the aberrantly glycosylated α3β1 integrin, it suppresses macrophage activation and effector functions, including phagocytosis—the process by which immune cells engulf and destroy cancer cells. The tumor’s sugar-coated disguise thereby subverts the immune system’s surveillance, allowing malignant cells to thrive undetected and unchallenged within the host.

To counter this sophisticated immune evasion strategy, the Northwestern scientists engineered monoclonal antibodies specifically designed to block the interaction between Siglec-10 and the sialylated integrin α3β1. These antibodies effectively interrupt the suppressive glyco-signaling axis, liberating macrophages from the inhibitory brakes imposed by the tumor’s sugar coat. Laboratory experiments with cultured cells demonstrated a marked reactivation of macrophage phagocytic function once the antibody was applied, promoting the clearance of pancreatic cancer cells.

The preclinical evidence was strengthened by in vivo studies utilizing two distinct mouse models of pancreatic cancer. Treatment with the anti-Siglec-10/α3β1 integrin antibodies significantly slowed tumor progression and enhanced immune cell infiltration within the tumor microenvironment. These findings highlight not only the therapeutic potential of targeting glyco-immune checkpoints but also the crucial role of tumor glycosylation patterns in shaping immune responses.

The path to developing these antibody therapies was complex and lengthy. The team screened thousands of hybridoma cell lines to isolate monoclonal antibodies with the specificity and affinity necessary to disrupt the Siglec-10 and integrin binding. It took roughly six years of painstaking work to identify lead candidates capable of blocking the tumor’s sugar-based stealth mechanism without disrupting normal cellular functions, underscoring the challenges inherent in translating sophisticated molecular insights into viable therapeutics.

Looking ahead, the research team plans to optimize these antibody candidates for compatibility with human immune systems and conduct early-phase clinical trials focused on safety and dosing. Additionally, synergistic combinations with conventional chemotherapy and existing immunotherapies are under investigation, with the aim of achieving not just tumor growth suppression but complete remission. By targeting this unique glyco-immune checkpoint, the researchers hope to break through the current barriers that have stymied effective treatment of pancreatic cancer.

Another critical focus of ongoing work includes the development of companion diagnostics. These tests will identify patients whose tumors prominently utilize the sialic acid–Siglec-10 pathway for immune evasion, enabling personalized treatment strategies that maximize therapeutic efficacy. Such precision medicine approaches are increasingly viewed as essential for overcoming cancer heterogeneity and improving patient outcomes.

Beyond pancreatic cancer, this study opens the door to investigating whether similar sugar-mediated immune evasion tactics are employed by other recalcitrant cancers, including glioblastoma and certain forms of ovarian and lung cancer. Moreover, these insights into glyco-immunology may have ramifications for treating chronic infectious diseases and autoimmune disorders, where immune regulation is likewise critical.

The research led by Associate Professor Mohamed Abdel-Mohsen at Northwestern University Feinberg School of Medicine exemplifies cutting-edge glyco-immunology, an emerging field that interrogates the intersection of carbohydrate chemistry and immune signaling. By leveraging detailed molecular understanding of sugar-protein interactions and their immunomodulatory effects, scientists are translating fundamental discoveries into transformative therapies designed to subvert cancer’s most cunning defenses.

As pancreatic cancer awareness intensifies during its dedicated awareness month, this innovative work offers tangible hope for patients facing one of the deadliest diseases worldwide. The five-year survival rate stagnates at approximately 13%, largely due to the tumor’s ability to evade immune destruction. The breakthrough investigation into the sugar-coat camouflage and its disruption heralds a promising new direction for immunotherapy against pancreatic cancer. While clinical translation will require several more years, this pioneering approach exemplifies the power of scientific perseverance, multidisciplinary collaboration, and molecular ingenuity to turn the tide against formidable cancers.

Subject of Research: Pancreatic cancer immune evasion via sialic acid–mediated glycosylation and integrin–Siglec-10 interactions

Article Title: Targeting Interactions Between Siglec-10 and α3β1 Integrin Enhances Macrophage-Mediated Phagocytosis of Pancreatic Cancer

News Publication Date: November 3, 2025

Web References:

• Cancer Research DOI: 10.1158/0008-5472.CAN-25-0977

Image Credits: Northwestern University

Keywords: Pancreatic cancer, glycoproteins, monoclonal antibodies, immunotherapy, cancer immunotherapy