Cell changes around early breast cancers provide clues into why some cases become invasive

UT MD Anderson News Release November 12, 2026

• Ductal carcinoma in situ (DCIS) can become invasive breast cancer, but not all cases will progress and many patients undergo unnecessary treatments
• Researchers created a detailed map of the cells surrounding DCIS, the most common form of stage 0 breast cancer
• Changes linked to invasive breast cancer appear to begin earlier than previously thought
• Findings could one day help doctors predict which patients need aggressive treatment and which patients may safely avoid it

Researchers at The University of Texas MD Anderson Cancer Center have created one of the most detailed maps to date of the cell environment surrounding ductal carcinoma in situ (DCIS), the most common form of preinvasive, or stage 0, breast cancer. The findings may help explain why some lesions progress to invasive breast cancer and others do not, informing strategies to improve patient risk prediction and develop better targeted approaches for patients at higher risk of invasive disease.

The study, published today in Science, was co-led by Nicholas Navin, Ph.D., chair of Systems Biology; Savitri Krishnamurthy, M.D., professor of Anatomical Pathology; Alastair Thompson, M.D., surgical oncologist at Baylor College of Medicine, as well as co-first authors Siyuan He, Ph.D., and Aatish Thennavan, Ph.D., postdoctoral fellows of Systems Biology at UT MD Anderson.

“DCIS is considered a snapshot before breast cancer becomes invasive, but not all DCIS cases progress to invasive disease, and the biology surrounding these lesions has been challenging to examine,” Navin said. “This atlas reveals the surrounding cells and structures that may help disease become invasive. In the future, these findings may allow clinicians to better identify and treat patients with DCIS who are at higher risk of invasive progression while also avoiding unnecessary treatments for those at low risk.”

What is DCIS and what do we know about its tumor microenvironment?

DCIS occurs when abnormal cells grow inside the breast milk ducts but have not yet spread into surrounding tissue. It is considered to be a precursor to the most common type of breast cancer. Mammograms and other breast examinations have increased the detection of DCIS cases, but many of these lesions never progress to invasive disease, making it challenging to determine which patients actually need more aggressive treatment.

While genetic changes in DCIS have been well-studied, little is known about its tumor microenvironment – the community of immune cells, blood vessels and tissue cells that surround and interact with the cancer cells. This led the researchers to generate a comprehensive atlas for DCIS.

How did the researchers create this map and what did it show?

Using advanced single-cell and spatial profiling technologies, the researchers mapped more than 850,000 cells from samples of normal breast tissue, DCIS and invasive breast cancer. They identified extensive changes in cancer cells and the surrounding microenvironment as disease progressed. The detailed atlas suggests that important biological features associated with invasive breast cancer begin to emerge earlier than previously known.

The study also uncovered previously unknown “cancer stromal loops,” ring-like structures made of supportive tissue and vascular cells that surround DCIS lesions, which create conditions that support tumor growth.

What does this mean for researchers and patients with breast cancer?

Additional research is needed to validate these findings and evaluate their potential use in future diagnostic tools and prevention or treatment strategies. Researchers will continue studying the cellular features identified in this atlas to determine whether they can predict which DCIS lesions are most likely to become invasive in order to better determine the best strategies for individual patients.

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This research was supported in part by the National Cancer Institute, the Cancer Prevention and Research Institute of Texas (CPRIT), the Vivian L. Smith Foundation, and UT MD Anderson institutional funding.  For a full list of collaborating authors, disclosures and funding sources, see the full paper in Science.