A new study published in The American Journal of Pathology has identified a distinct molecular program linking obesity with the progression of early-stage premalignant breast lesions to invasive breast cancer. The findings provide new insights into how obesity influences disease progression and suggest that metabolic stress adaptation, rather than the conventional pathways typically associated with tumor invasion, may play a central role in malignant transformation.
Obesity is a major and growing risk factor for breast cancer worldwide. Excess body weight has been associated not only with an increased risk of developing breast cancer but also with poorer clinical outcomes and an increased likelihood of disease recurrence. However, the biological mechanisms through which obesity promotes breast cancer progression have remained incompletely understood.
The study focused on ductal carcinoma in situ (DCIS), a non-invasive form of breast cancer classified as stage 0 disease that accounts for nearly one-quarter of newly detected breast lesions. Although women diagnosed with DCIS have an increased lifetime risk of developing invasive ductal carcinoma (IDC), only a proportion of these lesions progress to invasive disease. Determining which lesions are likely to become invasive remains one of the major challenges in breast cancer management.
Using advanced molecular and spatial transcriptomic analyses, researchers identified an obesity-associated biological profile characterized by metabolic stress adaptation, chronic inflammation, and remodeling of the tumor microenvironment. Rather than activating the classical molecular pathways linked to tumor invasion, obesity appeared to promote cellular mechanisms that enable breast tissue to adapt to persistent metabolic stress, thereby creating conditions that favor disease progression.
A notable finding was the increased expression of sulfatase 2 (SULF2), an extracellular enzyme involved in regulating cell signaling pathways associated with tissue remodeling and tumor development. The upregulation of SULF2 suggests that it could serve as a potential biomarker for identifying lesions at high risk of progression and may represent a promising therapeutic target.
The researchers also demonstrated that the transition from DCIS to invasive breast cancer is driven by coordinated interactions among epithelial, stromal, and immune cell populations. Obesity was found to influence each of these tissue compartments while simultaneously altering the signaling pathways that connect them, highlighting the complex relationship between metabolic health and tumor biology.
Advanced spatial transcriptomic analysis further showed that the local tissue environment plays a critical role in determining invasive potential. Unlike conventional bulk tissue analysis, spatial transcriptomics preserves the spatial organization of cells within the tissue, allowing researchers to identify cellular interactions that would otherwise remain undetected.
The findings indicate that current prognostic models, which primarily rely on cancer cell markers, may not adequately predict the risk of invasive disease in individuals with obesity. Incorporating metabolic health, immune cell composition, and obesity-associated molecular characteristics into diagnostic and prognostic models could improve risk stratification and facilitate more personalized treatment strategies.
The study also identified several obesity-associated molecular pathways, including oxidative stress responses, inflammatory signaling, extracellular matrix remodeling, and SULF2 upregulation, as potential therapeutic targets. These pathways may provide new opportunities for interventions aimed at preventing or delaying the progression of premalignant breast lesions.
The researchers further emphasized the importance of incorporating metabolic factors, including obesity and diabetes, into breast cancer risk assessment and treatment planning. As obesity rates continue to increase globally, integrating metabolic health into precision oncology approaches may improve early detection, refine prognostic models, and support individualized treatment strategies for patients at increased risk of invasive breast cancer.
Reference
- Hladik C, Sekhri M, Cen HH, Elaya Pillai SP, Lee S, Gao B, et al. Spatially resolved obesity-driven molecular changes in early breast cancer. Am J Pathol. 2026.