Researchers at the Icahn School of Medicine at Mount Sinai report that a rare subset of dendritic cells—specifically dendritic cell type 1—functions as the key architect of tertiary lymphoid structures (TLSs) inside tumors. These immune “outposts” act as on-site command centers where cancer-fighting responses are coordinated locally rather than relying on distant lymph nodes.
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
