Fibroblast dynamics during mammary oncogenesis: senescence, Wnt9a and beyond

Mammary gland fibroblasts are highly plastic and transition through distinct states during development and disease. A new study by Pascual et al (2025) provides a comprehensive single-cell atlas of murine mammary stromal cell hierarchies, revealing dysregulation of progenitor-driven fibroblast lineages in breast cancer and a senescence role of Wnt9a in cancer-associated myofibroblasts.