The work, published online July 16, 2026 in Science (DOI:10.1126/science.ady1678), addresses a long-standing question in cancer immunology: patients whose tumors contain TLSs tend to live longer and respond better to immunotherapies, yet the mechanisms that create and sustain these structures were unclear.

Using advanced multiplex imaging and spatial gene analysis, the team examined tumor samples spanning lung, liver, colorectal, kidney, and ovarian cancers. They visualized where dendritic cells were positioned within the tumor microenvironment and mapped which immune cell populations they physically and functionally interacted with.

To test causality, the researchers engineered a new mouse model that closely reproduces TLS features seen in human cancers. With this system, they selectively removed, activated, or genetically modified dendritic cells at defined stages of tumor progression, allowing the investigators to evaluate how TLS formation and persistence depend on these cells over time.

The results show that dendritic cells are essential not only for establishing TLSs, but also for maintaining their integrity as tumors evolve. Rather than performing a transient “alarm” role, dendritic cells remain in place and continuously orchestrate immune activity within the tumor.

Once TLSs are established, these cells coordinate interactions between T cells and B cells, supporting both cellular and humoral arms of anti-tumor immunity. In this model, the tumor becomes a self-contained immunological hub, promoting sustained immune pressure.

The authors emphasize that dendritic cells do more than activate individual immune components: they synchronize multiple pathways of defense, effectively enabling coordinated attacks where they are most needed.

This mechanism also points toward translational opportunities. Therapeutic strategies that increase dendritic cell abundance or boost dendritic cell type 1 function could strengthen TLS formation, potentially improving responses to existing immunotherapies—especially in patients who currently show limited benefit.

The study concludes that TLSs can become durable immune platforms driven by dendritic cell organizers, offering a roadmap for therapies aimed at longer-lasting control of cancer and reducing recurrence.

Subject of Research: Human tissue samples
Article Title: Dendritic cells control tertiary lymphoid structure development and maintenance in cancer
News Publication Date: 16-Jul-2026
Web References: http://dx.doi.org/10.1126/science.ady1678
References: Mattiuz et al., Science (2026) DOI:10.1126/science.ady1678
Image Credits: Mattiuz et al., Science (2026)

Keywords: Cancer immunology, tertiary lymphoid structures, dendritic cells, tumor microenvironment, spatial gene analysis, T cells, B cells, immunotherapy

The research indicates that blocking MARCO alters the behavior of immune cells within the tumor microenvironment. This alteration results in an increased influx of immune cells, which subsequently augments the effectiveness of anti-CTLA4 treatments. This development is particularly significant for what are termed "cold" tumors—cancers that typically lack sufficient immune cell presence and often prove resistant to conventional immunotherapies. The findings suggest that targeting MARCO can help mobilize the immune system in a way that was previously unattainable for many patients suffering from these challenging tumor types.

James Mulé, who serves as the associate center director for Translational Science at Moffitt and leads the study, articulated the research’s implications by noting that targeting MARCO could bolster the efficacy of existing immunotherapeutic drugs without necessitating the depletion of macrophages. This finding not only introduces a new paradigm for treating melanoma but also lays the groundwork for broader application in various types of cancers, providing hope to those in need of innovative treatment options.

Investigators performed an experimental study utilizing animal models, wherein they introduced a monoclonal antibody aimed at MARCO, observing its effects when combined with anti-CTLA4 therapy. The results were striking: the combination treatment led to a substantial increase in immune cell infiltration within the tumor. Dendritic cells, which are instrumental in priming the immune response against tumors, showed particular enhancement in their numbers following the combination therapy, highlighting the synergistic potential of this new approach.

It is intriguing to note that this study specifically mentioned that similar improvements were not observed when anti-MARCO therapy was paired with anti-PD1 treatment. This distinction underscores the unique role MARCO plays in enhancing anti-CTLA4 efficacy. The researchers emphasize the necessity of further dissecting the underlying mechanisms at play to better understand the immunological dynamics following MARCO inhibition.

Furthermore, the study opens doors for clinical trials aimed at integrating MARCO-targeting strategies into both neoadjuvant and adjuvant therapy settings. By mitigating the chances of cancer recurrence through enhanced immune preparation within the tumor microenvironment, the findings could significantly reshape our approach to cancer prevention and treatment.

Publications such as these have essential implications not only for melanoma treatment but also for a multiplicity of cancers where current therapies fall short. This research underlines the importance of continual innovation in cancer treatment modalities, striving to provide more comprehensive care to patients.

The significance of this study cannot be overstated, as it brings to light the intricate interplay between immune cells and tumor cells and emphasizes the need for tailored therapies that resonate with the biology of the disease. As Moffitt Cancer Center continues to push the envelope in cancer research, this study represents a vital stepping stone toward more effective and personalized treatment options for patients battling cancer.

In conclusion, the targeting of MARCO presents a promising avenue for enhancing the efficacy of immunotherapy for melanoma and potentially other cancers. The implications of this research are profound, suggesting that a redefined approach to immuno-oncology could lead to substantial improvements in patient outcomes. These findings herald an exciting future in cancer therapy, where personalized medicine and innovative strategies converge for better patient care.

Subject of Research: Animals
Article Title: Targeting MARCO in combination with anti-CTLA-4 leads to enhanced melanoma regression and immune cell infiltration via macrophage reprogramming
News Publication Date: March 13, 2025
Web References: Moffitt Cancer Center
References: Journal for ImmunoTherapy of Cancer
Image Credits: None provided
Keywords: Immunotherapy, melanoma, MARCO, anti-CTLA4, cancer research, immune cells, tumor microenvironment, clinical trials, personalized medicine.