A groundbreaking study from The University of Texas MD Anderson Cancer Center has revealed that normal breast cells in healthy women may exhibit chromosome abnormalities typically associated with invasive breast cancer, challenging long-held beliefs about the genetic origins of the disease.

The research involved analyzing breast tissue samples from 49 healthy women undergoing breast reduction surgery, allowing for a direct comparison of chromosomal changes in normal tissues with clinical breast cancer data.

Utilizing advanced techniques such as single-cell sequencing and spatial mapping, researchers focused on breast epithelial cells, which are believed to be precursors to cancer.

The study identified common chromosomal changes, including additional copies of chromosome 1q and losses of chromosomes 10q, 16q, and 22, which are also found in invasive breast cancers and linked to specific cancer-associated genes.

Data indicated that the aneuploid cells represented known cell lineages of the mammary gland, displaying distinct gene signatures related to estrogen receptor positivity and negativity, suggesting different potential origins for ER-positive and ER-negative breast cancers.

Significant correlations were found between a woman's age and the frequency of aneuploid cells, indicating that older women accumulate more cellular changes over time.

Navin, a lead researcher, emphasized the need for further longitudinal studies to explore risk factors that could lead these aneuploid cells to become cancerous, suggesting that the implications of these findings may extend beyond breast cancer.

The study received substantial support from multiple institutions, including the National Cancer Institute and the American Cancer Society, highlighting the importance of institutional backing in cancer research.

This research builds on previous work from the Human Breast Cell Atlas, which mapped over 714,000 cells to create a detailed genetic profile of normal breast tissue.

Results showed a median of 3.19% of epithelial cells were aneuploid, with over 82.67% exhibiting copy number changes typical of invasive breast cancers.

While not everyone may have precancerous conditions, the study underscores the necessity for larger investigations to understand the broader implications for cancer development.

Acknowledgments for the research are available in the published study, reflecting the collaborative effort behind this significant scientific inquiry.