The expanding frontier of mesenchymal stromal/stem cells (MSCs) in oncology research reveals a complex and multifaceted role of these cells in both tumor initiation and progression, as well as emerging therapeutic strategies. MSCs, traditionally recognized for their crucial function in maintaining tissue homeostasis across various organ systems, are increasingly appreciated for their dual nature in cancer biology. In diverse malignancies, including ovarian, breast, brain, hematologic, and colorectal cancers, MSCs are key players orchestrating the tumor microenvironment, influencing tumor growth trajectories, metastatic potential, and resistance to conventional therapies. This intricate involvement makes the study of MSCs a cornerstone for understanding tumor biology and developing innovative cancer treatments.
At the cellular level, MSCs exhibit remarkable plasticity, allowing them to adapt and respond dynamically within both normal and pathological tissue contexts. Their recruitment to neoplastic sites is driven by various chemoattractant signals released by tumor cells and associated stromal elements. Once localized, MSCs engage in reciprocal interactions with tumor cells and immune infiltrates, sculpting a microenvironment that often favors malignancy’s progression. These cells contribute to the remodeling of the extracellular matrix (ECM), secretion of pro-tumorigenic cytokines, and modulation of immune cell phenotypes—factors that collectively potentiate tumor aggressiveness and the maintenance of cancer stem cell niches.
Critically, recent research underscores the epigenetic reprogramming of MSCs in the tumor milieu, which shifts their phenotype from tumor-suppressive to tumor-supportive states. This plasticity is governed by chromatin remodeling, DNA methylation changes, and non-coding RNA activity, which recalibrate MSC gene expression and secretome profiles. Such reprogrammed MSCs secrete factors that enhance tumor cell proliferation, invasiveness, and survival. Understanding these epigenetic mechanisms provides new avenues for therapeutic interventions aimed at re-educating or targeting MSCs to restore their homeostatic and anti-tumor functionality.
In the context of tumor initiation, MSCs are emerging as potential facilitators of carcinogenesis. By creating a permissive stromal environment characterized by inflammation, oxidative stress, and altered stromal-epithelial crosstalk, MSCs may prime tissues for malignant transformation. Chronic exposure to tumorigenic signals alters MSC behavior, pushing them into a pro-inflammatory state that can destabilize genomic integrity in neighboring epithelial cells, thereby fostering cancer development. These insights challenge the conventional view of MSCs solely as passive stromal elements and highlight their active role in the early stages of tumorigenesis.
Another intriguing aspect of MSC biology is their sophisticated immune-modulatory capacity within tumors. MSCs can suppress cytotoxic T cell activity and promote the polarization of macrophages towards tumor-promoting phenotypes. They achieve immunosuppression through the secretion of indoleamine 2,3-dioxygenase (IDO), prostaglandin E2 (PGE2), and transforming growth factor-beta (TGF-β), thereby orchestrating an immune-privileged niche favorable for tumor survival. This immunomodulation not only aids tumor evasion from host defenses but also complicates the efficacy of immunotherapies. The evolving mechanistic understanding of MSC-mediated immune regulation is pivotal for designing combination therapies that can overcome immune escape.
Therapeutically, MSCs represent a double-edged sword—both as targets and tools. On the one hand, disrupting MSC-mediated support of tumors through inhibitors targeting their recruitment, survival, or function holds promise to stall tumor progression. On the other hand, harnessing MSCs’ innate tumor-homing abilities provides a novel vehicle for targeted drug delivery. Genetic engineering of MSCs to express anti-cancer agents, pro-apoptotic factors, or immune stimulators is an exciting frontier in precision oncology, offering localized therapeutic effects while minimizing systemic toxicity.
Current preclinical and clinical studies are exploring MSC-based therapeutics, ranging from modified MSCs capable of delivering cytotoxic molecules to the tumor, to MSCs engineered to secrete immune checkpoint blockers. However, the challenges are significant—including ensuring the stability and safety of engineered MSCs, avoiding potential pro-tumorigenic side effects, and overcoming the inherent heterogeneity of MSC populations. Rigorous characterization of MSC subsets and standardization of isolation and culture protocols are essential steps toward effective clinical translation.
The intricate interplay between MSCs and the cancer stem cell (CSC) population further complicates the tumor ecosystem. MSCs foster CSC maintenance by providing essential niche factors that promote self-renewal, dormancy, and therapy resistance. This interaction underlies the notorious difficulty in eradicating tumors completely, as CSCs can repopulate tumors and drive metastasis. Therefore, disrupting the MSC-CSC axis could represent a strategic vulnerability in cancers highly dependent on stem-like cells for progression.
Moreover, MSCs contribute to the metastatic cascade by facilitating tumor cell intravasation, survival in circulation, and colonization at distant sites. The molecular signaling pathways involved include CXCL12/CXCR4 chemotaxis, secretion of matrix metalloproteinases (MMPs), and enhancement of epithelial-to-mesenchymal transition (EMT) programs. Targeting these pathways in MSCs could impede metastasis, offering significant survival benefits for patients with advanced disease.
From a molecular perspective, detailed omics approaches—transcriptomic, proteomic, and metabolomic profiling—illuminate the diverse functional states of MSCs in the tumor stroma. These high-resolution datasets reveal context-dependent MSC phenotypes and identify novel biomarkers predictive of prognosis and therapeutic response. Integrating such multi-omics data with functional assays will refine patient stratification and tailor MSC-centric interventions.
Importantly, the dynamic co-evolution of MSCs and tumor cells presents a moving target, necessitating adaptive therapeutic strategies. Real-time monitoring of MSC phenotypes during therapy using non-invasive imaging and biomarker assessments may enable timely modulation of treatment regimens, improving outcomes. Future research must also delineate how systemic factors such as aging, metabolic syndrome, and therapy-induced inflammation modulate MSC behavior in cancer.
In conclusion, MSCs sit at the nexus of tumor biology, embodying both the promise and challenge of cancer stromal research. Their dualistic nature—capable of both tumor suppression and support—implicates them as potent regulators of the malignant environment. Unlocking the molecular underpinnings of MSC plasticity, immune modulation, and their symbiotic relationships with tumor and immune cells paves the way for novel, targeted interventions. As MSC-based therapies progress from bench to bedside, a cautious yet optimistic outlook endures for harnessing these cells to outmaneuver cancer’s adaptive resilience.
Sustained interdisciplinary efforts blending stem cell biology, oncology, immunology, and bioengineering are crucial in driving innovation. The path ahead demands rigorous mechanistic studies coupled with thoughtfully designed clinical trials to harness the full potential of MSC-targeted strategies. As our comprehension deepens, MSCs could transform from enigmatic supporters of malignancy to powerful allies in the fight against cancer.
Subject of Research:
Mesenchymal stromal/stem cells (MSCs) and their role in tumor initiation, progression, and therapeutic applications in cancer.
Article Title:
Mesenchymal stromal/stem cells in tumour initiation, progression and therapy
Article References:
Garcia, G.L., Baruwal, R., Suresh, S. et al. Mesenchymal stromal/stem cells in tumour initiation, progression and therapy. Nat Rev Cancer (2026). https://doi.org/10.1038/s41568-026-00936-w
Image Credits: AI Generated
