For years, cancer research has treated tumor cells as relatively stable enemies: cells that multiply, spread and acquire resistance through genetic mutations. A study published in Cell Death Discovery challenges that simplified view in non-small cell lung cancer, suggesting that some of the most dangerous tumor cells can change their behavior in response to the immune cells surrounding them. The research by Alessandro Zeuner, Giulia Sette, Sara Rossi and colleagues focuses on the relationship between lung cancer stem cells and macrophages, immune cells that can either attack tumors or, under certain conditions, become powerful supporters of cancer progression.
The study describes how specialized regions known as macrophage niches can influence the biological state of non-small cell lung cancer stem cells. A niche is more than a physical location inside a tumor. It is a dynamic microenvironment made up of immune cells, connective-tissue cells, blood vessels, signaling molecules and extracellular matrix components. Together, these elements provide chemical and mechanical instructions that can alter how cancer cells grow, move, survive and respond to treatment. In this setting, macrophages appear to help push tumor cells into flexible states associated with dormancy, epithelial–mesenchymal transition and drug resistance.
Cancer stem cells are a small but important population within many tumors. Unlike the majority of cancer cells, they can self-renew and generate different tumor cell types, allowing a malignancy to rebuild itself after treatment. Their ability to remain alive in a slow-growing or non-dividing state is particularly significant. Dormant cells may escape therapies designed to kill rapidly dividing cells, then become active again months or years later. This biological “pause” can help explain why a patient may initially respond well to treatment but later experience relapse.
The research links macrophage-rich environments to this dormant behavior. Macrophages are part of the innate immune system and normally remove damaged cells, coordinate inflammation and support tissue repair. Tumors can reshape these cells through chemical signals, creating tumor-associated macrophages that often suppress immune attacks and promote tissue remodeling. Within lung tumors, these macrophages may release growth factors, cytokines and other signaling molecules that activate survival programs in cancer stem cells. Instead of simply stimulating proliferation, the signals can encourage cells to enter a protected, low-activity state.
A central concept in the study is tumor plasticity, the ability of cancer cells to change their characteristics without necessarily acquiring new genetic mutations. This flexibility allows a tumor cell to shift between states depending on environmental pressure. A cell may become highly invasive during one phase, dormant during another and actively dividing when conditions improve. Such changes are controlled through networks involving transcription factors, cell-surface receptors, metabolic pathways and epigenetic modifications, which alter gene activity without changing the underlying DNA sequence.
The researchers also connect macrophage niches with epithelial–mesenchymal transition, commonly known as EMT. During EMT, cells lose features associated with epithelial tissue, such as strong cell-to-cell adhesion, and acquire mesenchymal traits that increase mobility and invasiveness. In cancer, EMT can help tumor cells detach from the primary mass, migrate through surrounding tissue and enter the bloodstream. It is also associated with stem-like properties and resistance to several forms of therapy. The study suggests that macrophage-derived signals may help lung cancer stem cells move along this spectrum, linking dormancy and metastatic potential rather than treating them as separate phenomena.
Chemoresistance is another major consequence of this cellular flexibility. Many chemotherapy drugs are most effective against cells that are actively replicating or depend heavily on particular metabolic pathways. Dormant cancer stem cells may avoid these vulnerabilities by reducing proliferation and changing their metabolism. EMT-associated cells can also increase drug-export mechanisms, strengthen DNA-damage responses and activate anti-apoptotic pathways that prevent programmed cell death. If macrophage niches maintain these protective states, they could act as local shelters where cancer cells survive treatment and later repopulate the tumor.
These findings may help explain why targeting tumor cells alone is often insufficient. A therapy can eliminate a large fraction of malignant cells while leaving behind a smaller population protected by its microenvironment. The results point toward combination strategies that attack both cancer stem cells and the macrophage signals supporting them. Potential approaches could include therapies that reprogram tumor-associated macrophages, block specific communication pathways between macrophages and cancer cells, or force dormant cells into a vulnerable state before conventional treatment. Such strategies remain an area of investigation and would require careful testing because macrophages also perform essential functions in normal immunity and tissue repair.
The study does not suggest that every macrophage in every lung tumor behaves identically, nor that dormancy, EMT and drug resistance are controlled by a single mechanism. Tumors are highly diverse, and the behavior of a macrophage niche can depend on its location, molecular composition and interaction with other immune and stromal cells. Translating these observations into patient treatments will require determining which signaling pathways are most important in individual tumors and identifying reliable biomarkers that reveal when cancer stem cells are being protected by their surroundings. Even so, the work reinforces a growing principle in cancer biology: treatment resistance is not solely a property of tumor cells, but can emerge from an ongoing conversation between malignant cells and the ecosystem around them.
Subject of Research: The role of macrophage niches and tumor plasticity in regulating dormancy, epithelial–mesenchymal transition and chemotherapy resistance in non-small cell lung cancer stem cells.
Article Title: Tumor plasticity in macrophage niches promotes dormancy, EMT and chemoresistance of non-small cell lung cancer stem cells.
Article References: Zeuner, A., Sette, G., Rossi, S. et al. “Tumor plasticity in macrophage niches promotes dormancy, EMT and chemoresistance of non-small cell lung cancer stem cells.” Cell Death Discovery (2026). https://doi.org/10.1038/s41420-026-03261-1
Image Credits: AI Generated
DOI: https://doi.org/10.1038/s41420-026-03261-1
Keywords: non-small cell lung cancer, cancer stem cells, macrophages, tumor microenvironment, tumor plasticity, dormancy, epithelial–mesenchymal transition, EMT, chemoresistance, cancer relapse
Tags: cancer cell dormancycancer therapy resistancechemoresistance mechanismsepithelial-mesenchymal transition in NSCLCimmune cell influence on tumor progressionlung cancer stem cellsmacrophage nichesmacrophage-cancer cell interactionsnon-small cell lung cancer microenvironmenttumor cell plasticitytumor immune microenvironmenttumor microenvironment
