How Obesity Rewires Breast Cancer's Path From DCIS to Invasion

In an interview with Targeted Oncology^TM, Bethany Hannafon, PhD, and Elizabeth Wellberg, PhD, discuss a study that investigated how obesity shapes the molecular landscape of early breast cancer, specifically the transition from ductal carcinoma in situ (DCIS) to invasive ductal carcinoma (IDC). Using spatially resolved digital spatial transcriptomics (GeoMx DSP), researchers profiled epithelial (CK+), stromal (α-SMA+), and immune (CD45+) compartments from 19 breast tissue specimens, stratified by body mass index (BMI) into nonobese (≤29.9 kg/m²) and obese (≥30 kg/m²) groups, with findings validated in an independent cohort.

The results revealed that the invasive transition follows fundamentally different molecular paths depending on host BMI. In non-obese patients, the shift from DCIS to IDC followed a classical pattern driven by proliferation (E2F/G2M cell-cycle programs) and epithelial-to-mesenchymal transition. In obese patients, however, invasion was instead marked by a stress-adaptive phenotype featuring metabolic reprogramming, oxidative stress responses, and inflammatory signaling (TNF-α/NF-κB, IL-6/JAK/STAT3).

This epithelial shift was accompanied by fibro-inflammatory remodeling of the stroma and an immunosuppressive immune niche in obese tissue, characterized by B-cell depletion and enrichment of M2 macrophage-associated transcripts. A key molecular finding was consistent up-regulation of sulfatase 2 (SULF2), an enzyme involved in extracellular matrix remodeling, in obese epithelium—confirmed at the protein level via immunohistochemistry.

Together, these findings suggest that obesity does not simply accelerate the same invasive program seen in non-obese patients, but instead promotes an alternative, metabolically driven route to invasion. The authors note this is an exploratory, hypothesis-generating study limited by small cohort size, and call for larger studies incorporating detailed metabolic covariates. The results raise the possibility that standard prognostic markers based on proliferation may need to account for a patient's metabolic/obesity status for more accurate risk stratification.

REFERENCE

Hladik C, Sekhri M, Cen HH, et al. Spatially Resolved Obesity-Driven Molecular Changes in Early Breast Cancer. Am J Pathol. 2026 Jul;196(7):1471-1486. doi: 10.1016/j.ajpath.2026.03.016. Epub 2026 May 1. PMID: 42069142.