Scientists at HSE University have unveiled a pivotal molecular mechanism underpinning the aggressive nature of triple-negative breast cancer (TNBC), a subtype known for its resistance to existing targeted therapies and poor prognosis. Their groundbreaking research reveals that the driving forces for tumor progression stem not from the cancer cells themselves but from the intricate ecosystem of the tumour microenvironment, fundamentally reshaping our understanding of TNBC biology and highlighting new avenues for therapeutic intervention.
Triple-negative breast cancer accounts for approximately 20% of breast cancer cases worldwide. Its hallmark is the absence of estrogen receptors (ER), progesterone receptors (PR), and human epidermal growth factor receptor 2 (HER2). This receptor-negative status precludes the use of hormonal or HER2-targeted treatments, severely limiting therapeutic options. Clinically, TNBC disproportionately affects younger women, exhibits rapid metastatic potential, and is burdened by a high rate of early recurrence and mortality. These aggressive characteristics have positioned TNBC as a critical challenge in oncology.
Given the lack of conventional molecular targets in TNBC, research efforts have expanded beyond the malignant cells to encompass their surrounding environment. The tumour microenvironment comprises a dynamic consortium of connective tissue, immune cells, fibroblasts, extracellular matrix components, and vasculature. This environment can paradoxically either impede or foster tumorigenesis, suggesting that its molecular interplay may hold keys to combating the disease.
In an innovative study published in Current Drug Therapy, a multidisciplinary team at the HSE Faculty of Biology and Biotechnology dissected the gene expression profiles of both TNBC tumour cells and their microenvironment components. By correlating these molecular data with extensive patient clinical records, they identified critical regulatory pathways influencing tumour aggressiveness and patient outcomes. Central to their discovery is the insulin-like growth factor 2 (IGF2), a well-known signalling protein implicated in tissue growth and repair, but hijacked in cancer to fuel unregulated proliferation.
Contrary to conventional assumptions that the tumour cells produce the essential growth-supporting factors, this study found that fibroblasts—connective tissue cells resident within the tumour microenvironment—are the predominant source of IGF2 in TNBC. These fibroblasts, normally maintaining tissue architecture and homeostasis, seem to switch roles under the pathological state, becoming facilitators of cancer progression by secreting IGF2, effectively “fueling the fire” of tumour expansion.
Adjacent to this growth-promoting mechanism, the tumour possesses an intrinsic regulatory system aimed at tempering unchecked development. This restraint is mediated by the insulin-like growth factor binding protein 6 (IGFBP6), a molecular “trap” that binds IGF2, preventing it from excessive activation of tumour cells. Intriguingly, the researchers observed that both tumour and microenvironmental cells produce IGFBP6 as a counterbalance to growth stimuli, suggesting a finely tuned equilibrium under normal conditions.
The study’s clinical analysis revealed a troubling link between diminished IGFBP6 expression and heightened infiltration of macrophages within tumours. Macrophages, pivotal immune cells tasked with host defense, can undergo functional reprogramming in cancer to adopt tumor-supportive roles. This reprogramming fosters a pro-tumoral milieu, promoting angiogenesis, matrix remodeling, and immune suppression, factors collectively contributing to accelerated disease recurrence and poor prognosis in affected patients.
These findings carry immediate translational significance. Measuring IGFBP6 levels in tumour biopsies could serve as a prognostic biomarker, enabling clinicians to stratify patients by recurrence risk more accurately. High-risk individuals with low IGFBP6 expression and macrophage-enriched tumours might benefit from intensified surveillance and tailored therapeutic regimens, potentially improving survival outcomes.
Looking forward, the elucidation of this tumour microenvironment axis opens exciting prospects for the development of novel treatments. Current chemotherapeutic strategies targeting rapidly dividing cancer cells often fall short against TNBC’s resilience. Redirecting therapeutic focus to the supportive fibroblasts and immune components within the microenvironment offers a promising paradigm shift. For instance, elevating IGFBP6 levels pharmacologically or inhibiting IGF2 production in fibroblasts could undermine the tumour’s growth advantage, effectively “starving” cancer cells of their supportive niche.
Maxim Shkurnikov, leading the research at HSE’s Laboratory for Research on Molecular Mechanisms of Longevity, emphasizes this strategic reorientation: “Conventional chemotherapy primarily targets rapidly dividing cells, and in triple-negative breast cancer this is often insufficient. We propose shifting the focus to the tumour microenvironment and targeting the cells that support tumour growth. By modulating IGFBP6 and IGF2 dynamics, we hope to develop therapies that significantly reduce the risk of rapid recurrence.”
This research underscores the critical importance of the tumour microenvironment in dictating cancer progression and recurrence, particularly in TNBC, where options remain limited. It aligns with a growing body of evidence suggesting that addressing not only the malignant cells but also the surrounding stromal and immune components is essential for durable therapeutic success.
Moreover, this discovery may have implications beyond TNBC, offering insights into other malignancies where the IGF axis and immune microenvironment interplay governs tumour behavior. The identification of biomarkers like IGFBP6 and the delineation of fibroblast-derived IGF2 in cancer progression herald a new wave of personalized oncology approaches grounded in microenvironmental biology.
In summary, the HSE University study marks a significant advance in cancer biology, highlighting that the aggressive nature of triple-negative breast cancer is not solely an intrinsic feature of tumour cells but critically influenced by their microenvironment. By targeting these auxiliary cells and their molecular signals, there lies an opportunity to outmaneuver this formidable disease and improve outcomes for patients currently facing limited options.
Subject of Research: Molecular mechanisms and tumour microenvironment in triple-negative breast cancer
Article Title: IGFBP6 Expression Correlates with Macrophage Presence in Triple-Negative Breast Cancer Tumors
News Publication Date: 2 January 2026
Web References:
https://doi.org/10.2174/0115748855416908251120055038
References:
HSE University research team, Current Drug Therapy, 2026
Keywords:
Triple-negative breast cancer, tumour microenvironment, IGF2, IGFBP6, fibroblasts, macrophages, cancer recurrence, molecular oncology, tumour progression, targeted therapy, immune cells, cancer biomarkers
