Radiotherapy in girls and the risk of breast cancer later in life

Exposing young women and girls under the age of 20 to ionizing radiation can substantially raise the risk of their developing breast cancer later in life. Scientists may now know why. A collaborative study, in which Berkeley Lab researchers played a pivotal role, points to increased stem cell self-renewal and subsequent mammary stem cell enrichment as the culprits. Breasts enriched with mammary stem cells as a result of ionizing irradiation during puberty show a later-in-life propensity for developing ER negative tumours