The research found that nearly all participants had about 3% of their breast cells exhibiting cancer-associated genetic alterations, despite appearing healthy.

Lead author Dr. Samuel Aparicio highlighted that while these mutations are harmless on their own, they could serve as foundational elements for future cancer development.

The identified mutations, known as copy number alterations, involve the duplication or loss of large DNA segments, which the body typically corrects through its DNA repair mechanisms.

A recent study published in Nature Genetics utilized advanced single-cell gene sequencing technology to analyze breast cells from 28 women, revealing genetic alterations primarily in luminal cells, which are thought to be the origin of major breast cancer types.

If these mutations remain undetected or unrepaired, they could accumulate over time, potentially leading to cancer.

The study raises important questions about how and when mutations accumulate in breast cells and suggests that similar research could enhance our understanding of cancer in other organs.

The methodology employed in this study allowed for a comprehensive analysis of rare genetic events that are not detectable with standard sequencing techniques.

Some women, particularly those with high-risk BRCA1 and BRCA2 variants, exhibited cells with six or more mutations, suggesting a progression from normal to cancer-like cells.

These findings indicate that the presence of rare genetic anomalies may serve as early indicators of potential breast cancer development, highlighting the need for further investigation.

Co-senior author Dr. Joan Brugge noted that the accumulation of genetic alterations in luminal cells supports the idea that these changes predispose them to cancer.

The research team, led by Vinci Au, Dr. Michael Oliphant, and Dr. Marc Williams, received support from several institutions, including the Gray Foundation and the US National Cancer Institute.

Understanding these low-level mutations could inform preventive strategies and early detection methods for breast cancer.