Immune checkpoint inhibitors have transformed treatment for several advanced cancers by releasing molecular brakes that prevent T cells from attacking malignant cells. Anti-PD-1 drugs work by blocking the interaction between PD-1 on T cells and its ligands on tumor or immune cells, allowing exhausted T cells to regain some of their cytotoxic activity. However, colorectal cancer remains a particularly difficult setting for immunotherapy. Only a subset of tumors responds effectively, and many patients who initially benefit eventually develop acquired resistance. The new findings suggest that chronic inflammation may help explain why this resistance develops, by changing not only the immune cells surrounding a tumor but also the internal regulatory machinery of the cancer cells themselves.

The study, published in Nature Communications, was led by Assistant Professor Takumi Itoh of the Department of Therapy Development and Innovation for Immune Disorders and Cancers at Juntendo University’s Graduate School of Medicine. The researchers examined human colorectal cancer samples using single-cell RNA sequencing and broader transcriptomic analyses, then tested their observations in human IL-26 transgenic mice and inflammation-induced mouse models. These approaches were combined with immunofluorescence imaging, chromatin immunoprecipitation sequencing, co-immunoprecipitation experiments, and targeted interventions directed against IL-26, STAT1, BRD4, CXCL chemokines, the chemokine receptor CXCR2, and neutrophils. Together, the experiments followed the mechanism from cytokine production by immune cells to epigenetic changes inside tumor cells and, ultimately, altered responses to immunotherapy.

The researchers found that IL-26-producing CD8-positive type 17 T cells accumulated in colorectal tumors that had become resistant to anti-PD-1 treatment. Type 17 T cells are associated with inflammatory immune responses and can produce cytokines that influence both neighboring immune cells and tissue cells. In this case, IL-26 behaved in an unusual way. Rather than acting solely through receptors at the cell surface, the cytokine was detected inside the nuclei of tumor cells. There, it interacted with signal transducer and activator of transcription 1, known as STAT1, a transcriptional regulator that can move into the nucleus after cytokine signaling and bind regulatory regions of DNA. The findings indicate that IL-26 helped assemble a transcriptional complex involving STAT1, nuclear factor kappa B, and bromodomain-containing protein 4, or BRD4.

BRD4 is an epigenetic reader: it recognizes acetylated histones, the proteins around which DNA is wrapped, and helps recruit machinery that activates gene transcription. By engaging BRD4, inflammatory signaling can produce changes in gene activity without changing the DNA sequence itself. The Juntendo team’s experiments showed that the IL-26–STAT1 interaction promoted BRD4-associated regulatory activity at regions controlling genes for several C-X-C motif chemokines, including CXCL1, CXCL2, CXCL3, and CXCL7. These molecules are powerful chemoattractants. Their expression increased by several thousand-fold in some experimental settings, indicating that the pathway could convert a relatively localized inflammatory signal into a large-scale remodeling of the tumor microenvironment.

The consequences were particularly significant for neutrophils. Chemokines such as CXCL1 and CXCL2 can recruit neutrophils through CXCR2, a receptor expressed on these cells. Although neutrophils are essential components of normal host defense, tumors can manipulate them into immunosuppressive states. Within the colorectal tumor models examined in the study, the influx of neutrophils was associated with weakened antitumor CD8-positive T-cell activity. These neutrophils helped create conditions in which cancer-directed T cells were less effective, even when PD-1 signaling was pharmacologically blocked. The result was a feedback loop in which inflammation promoted chemokine production, chemokines recruited suppressive neutrophils, and the altered immune environment allowed the tumor to evade immune destruction.

The researchers then tested whether disrupting different components of this pathway could restore treatment sensitivity. Blocking IL-26 reduced the inflammatory program in tumor cells. Inhibiting BRD4 interfered with the epigenetic machinery responsible for maintaining increased chemokine transcription. Targeting CXCR2 limited neutrophil recruitment, while direct depletion or inhibition of neutrophils reduced their suppressive influence within the tumor. In preclinical models, these interventions improved antitumor immune responses and enhanced the activity of anti-PD-1 therapy. The results point to the IL-26–STAT1–BRD4 axis as a possible therapeutic vulnerability, although the experiments do not yet establish that the approach is safe or effective in human patients.

The findings also broaden the understanding of how inflammatory cytokines can influence cancer biology. Cytokines are often described as soluble messengers that bind receptors and activate signaling cascades, but IL-26 appears capable of exerting a more direct influence on the tumor-cell nucleus. By coupling immune-derived signaling to epigenetic regulation, it may give cancer cells the ability to reshape the immune landscape around them. Dr. Itoh described IL-26 as a rare cytokine capable of inducing epigenetic changes in cancer cells and emphasized that the resulting increase in CXCL chemokines was strong enough to substantially alter the tumor microenvironment. This mechanism offers a molecular explanation for how chronic inflammation can become an active participant in immunotherapy resistance rather than merely a background feature of the disease.

The study raises the possibility of combining anti-PD-1 drugs with therapies directed against IL-26, BRD4, CXCR2, or neutrophil-mediated suppression. Such combinations could be especially relevant for patients whose tumors contain high levels of IL-26-producing type 17 T cells or show evidence of CXCL-driven neutrophil infiltration. Before clinical applications can be considered, researchers will need to determine how common this pathway is across colorectal cancer subtypes and other malignancies, whether IL-26 activity can be measured reliably in patients, and how broadly its blockade can be applied without disrupting protective immune functions. The study also includes potential conflicts of interest: several researchers are inventors and patent holders of a humanized anti-IL-26 antibody, while some authors hold relationships with a company connected to the technology. Even with these considerations, the work provides a detailed preclinical framework for understanding how inflammation, epigenetic remodeling, and immune escape can converge to undermine cancer immunotherapy.

By revealing that IL-26 can drive a STAT1- and BRD4-dependent transcriptional program in colorectal cancer cells, the researchers have identified a previously unrecognized connection between immune signaling and cancer-cell epigenetics. The pathway does not simply suppress T cells directly; it changes the tumor’s chemical environment, recruits neutrophils, and helps establish resistance to immune checkpoint blockade. If future studies confirm the mechanism in patients, blocking IL-26-driven reprogramming could become part of a new generation of combination strategies designed to make resistant tumors visible and vulnerable to the immune system again.

Subject of Research: Animals

Article Title: IL-26-driven epigenetic remodeling promotes immune evasion in colorectal cancer

Web References: https://doi.org/10.1038/s41467-026-75754-7

References: Takumi Itoh, Ryo Hatano, Yuta Hasegawa, Nao Hosokawa, Kazuyoshi Takeda, Ayako Yamamoto, Yoshiya Horimoto, Jinghui Yu, Hayato Nakamura, Harumi Saeki, Shogo Ehata, Shuji Matsuoka, Haruna Otsuka, Hiroshi Ohtsu, Michio Tomura, Nam H. Dang, Yutaro Kaneko, Kei Ohnuma, and Chikao Morimoto. “IL-26-driven epigenetic remodeling promotes immune evasion in colorectal cancer.” Nature Communications. DOI: 10.1038/s41467-026-75754-7

Image Credits: Dr. Takumi Itoh, Juntendo University, Japan

Keywords: IL-26, colorectal cancer, cancer immunology, immunotherapy resistance, anti-PD-1 therapy, epigenetic remodeling, STAT1, BRD4, CXCL chemokines, neutrophils, tumor microenvironment, cancer research

GATA6 traditionally functions as a molecular guardian that preserves the specialized state of gut lining cells, ensuring cellular stability by regulating gene expression programs integral to intestinal cell identity. However, this new research demonstrates that diminished GATA6 levels correlate strongly with increased metastatic capacity and poorer clinical outcomes in both murine models and human colorectal cancer patients. This points to GATA6 not merely as a passive marker but as an active suppressor of metastasis, the deadliest phase of cancer progression.

The scientific community has long grappled with the mystery of what triggers liver metastases in colorectal cancer. Unlike primary tumorigenesis, liver metastasis has defied explanations rooted in genetic drivers, with no singular mutations yet identified as the key initiators. Instead, this study highlights an epigenetic mechanism: the loss of GATA6 leads to a switch in gene regulatory networks that governs cellular plasticity, rather than a mutation in the DNA sequence itself. This transition endorses a flexible, stem-like phenotype conducive to metastatic competence.

To dissect the complex cellular changes underpinning metastasis, the researchers engineered organoid models derived from liver metastases. These three-dimensional culture systems faithfully recapitulate tumor architecture and behavior, enabling the tracking of cancer evolution in controlled laboratory settings. When these liver metastasis-derived organoids were retransplanted into the colonic environment of mice, they formed aggressively metastatic tumors that reiteratively displayed diminished GATA6 expression over successive generations. This experimental design gave unprecedented insight into early metastatic events that are often inaccessible in clinical biopsies.

Remarkably, the suppression of GATA6 unleashed a phenomenon termed lineage plasticity, whereby colorectal cancer cells abandon their rigid intestinal epithelial identity and revert to a primitive, fetal-like state. This plasticity endows them with the remarkable ability to migrate, survive in circulation, and colonize foreign microenvironments such as the liver. Intriguingly, this same plasticity underpins normal physiological processes like wound healing and tissue regeneration, exposing the cancer’s exploitation of developmental programs for malignant advantage.

One of the hallmark features of this GATA6-dependent plasticity is the loss of the intestinal stem cell marker LGR5. Normally, LGR5-positive cells play a crucial role in maintaining the gut epithelium. However, the researchers demonstrated that metastatic cells lacking GATA6 express a fetal-like gene signature and are LGR5-negative, a phenotype increasingly recognized as central to initiating liver metastases. Experimentally silencing GATA6 triggered a cell state switch from LGR5-positive to LGR5-negative, which directly enhanced metastatic potential.

Conversely, reintroduction of GATA6 or activation of its downstream signaling pathways re-imposed cellular identity and significantly curtailed the ability of cancer cells to metastasize in vivo. These findings catapult GATA6 into the limelight not only as a biomarker for metastatic risk but also as a promising therapeutic target. Unlike conventional strategies that focus on tumor size or proliferation rates, this research illuminates metastasis as a process driven by dynamic, cell-state transitions controlled epigenetically.

Mouse models genetically engineered to lack GATA6 in colorectal tumors exhibited a marked increase in both the frequency and burden of liver metastases, while primary tumor growth remained largely unaffected. This dissociation underscores that metastatic potential is governed more by the quality and plasticity of cancer cell states rather than their proliferative capacity. It calls for a fundamental rethinking of therapeutic interventions aimed at halting cancer spread by stabilizing cellular identity.

Looking forward, this pioneering research paves the way for novel clinical applications. Assessing GATA6 expression in patient tumors could stratify metastatic risk, guiding personalized monitoring and treatment regimens. Furthermore, therapeutic approaches designed to preserve or restore GATA6 function, or to inhibit the epigenetic plasticity it regulates, may thwart the early steps of metastasis, offering hope for improved colorectal cancer outcomes.

Targeting plasticity presents formidable challenges, as the underlying cellular processes are also essential for normal tissue repair and homeostasis. Future studies will need to precisely dissect the molecular circuitry that distinguishes malignant plasticity from physiological adaptation. Additionally, investigating how interactions between cancer cells and the tumor microenvironment—including immune components and liver-specific cues—influence these cell-state transitions may reveal exploitable vulnerabilities unique to metastatic cells.

The researchers intend to identify molecular weaknesses specific to GATA6-deficient cancer cells which could be selectively targeted with therapeutic agents. By combining these insights with organoid modeling and in vivo validation, they aim to develop targeted interventions that disrupt the metastatic cascade at its inception, preventing the lethal spread of colorectal cancer.

In sum, this landmark study reveals that the loss of a single transcription factor, GATA6, orchestrates a reprogramming of colorectal cancer cells towards a fetal-like, highly plastic state with enhanced metastatic capability. This discovery transforms our understanding of metastasis from a purely genetically driven process to an epigenetically controlled cellular identity shift. By establishing GATA6 as a crucial molecular switch, the research opens new avenues for early detection, prognosis, and therapeutic targeting in colorectal cancer, potentially altering the clinical management of this devastating disease.

Subject of Research: Mechanisms of colorectal cancer metastasis and the role of transcription factor GATA6 in cell identity and plasticity.

Article Title: Loss of GATA6 Induces Epigenetic Reprogramming Facilitating Liver Metastasis in Colorectal Cancer.

News Publication Date: 22-Jun-2026.

Image Credits: Norihiro Goto Lab.

Keywords: Cancer cells, Colorectal cancer, Metastasis, GATA6, Transcription factor, Cell plasticity, Epigenetics, Liver metastasis, Organoids, Cancer progression, Oncology, Cancer biomarkers.