University of Cambridge Mar 31 2026 Scientists have created the most detailed map to date, comprised of over 3 million cells, showing how breast tissue changes as women age – including dramatic changes during menopause. The map reveals how, as women age, the number of cells in their breast tissue decreases, and these in turn proliferate less, and the structure of breast tissue changes. This creates a 'micro-environment' in which cancer cells can thrive. Details of the study, led by scientists