Due to improved screening, DCIS now makes up about one-quarter of all breast cancer diagnoses. However, most cases of DCIS never progress to invasive breast cancer (IBC), meaning that many women undergo unnecessary aggressive treatments like surgery, radiation, and hormone therapy. Molecular predictors of which DCIS cases will progress remain poorly understood.
To better understand which DCIS cases are likely to progress to IBC, researchers studied nearly 200 breast tissue samples from DCIS patients who either stayed healthy or later developed invasive cancer. They analyzed the samples’ genes, DNA changes, and other molecular patterns. The results were published earlier this month in Breast Cancer Research.
The study concluded that DCIS is extremely diverse at the molecular level, even between patients with similar clinical features. No single gene could predict which cases would become invasive. However, groups of genes (pathways) were different between DCIS that stayed harmless and DCIS that became cancerous. In DCIS that later became invasive, there were stronger signals for processes like epithelial-mesenchymal transition (EMT) — where cells become more mobile and invasive. Researchers also found differences in DNA methylation (chemical changes to DNA) and gene splicing, but these alone weren’t strong enough to predict outcomes reliably. Some molecular features found in invasive cancers were already visible in DCIS that progressed — suggesting early warning signs exist.
This study suggests that in the future, genetic “risk signatures” could help doctors better identify which women need strong treatments and which could safely avoid them. It also highlights the need for larger, more detailed studies to create reliable, personalized treatment plans based on a tumor’s unique molecular makeup.