Comprehensive Atlas Reveals Aging's Impact on Breast Tissue and Cancer Risk

Researchers at The Jackson Laboratory (JAX) have created a detailed atlas of how healthy breast tissue ages, offering new insights into the cellular, molecular, and genetic changes that may increase the risk of breast cancer. The study, published in Nature Aging, provides an open-access resource for scientists to explore the relationship between aging and cancer risk.

Using advanced single-cell and spatial transcriptomics technologies, the team compared young and older female mice to map changes in mammary gland cellular landscapes over time. They found significant shifts in epithelial, immune, and stromal cells, which are crucial for maintaining healthy breast tissue. Specifically, epithelial cells lose their specialized functions, becoming more adaptable but also more prone to malignancy. Stromal cells lose their specialized identity, potentially creating an environment conducive to tumor growth. Additionally, immune cells infiltrate aging tissue but become prone to inflammation and exhaustion, possibly fueling tumor development.

"For the first time, we’ve linked aging-related gene expression changes in breast tissues to alterations in chromatin accessibility, the molecular ‘script’ controlling gene activity,” said Duygu Ucar,  co-senior author of the study. “This implies that as breast cells age, alterations in chromatin structure may play a crucial role in regulating gene activity.” 

Importantly, the team compared their mouse data to genetic profiles of human breast tumors. They discovered that age-related molecular signatures in mice closely mirror patterns seen in human breast cancers, suggesting that the aging breast microenvironment directly influences cancer risk.

Brittany Angarola, co-first author, noted, "Finding these overlapping pathways was really exciting. It suggests that aging-related shifts in healthy tissue might create a more cancer-friendly environment before tumors even form."