Convincing or at least strong evidence has been presented showing that genetic mutations such as BRCA1/BRCA2 or a family history of breast cancer, hormonal factors increasing the duration of exposure to oestrogens such as early menarche/late menopause/hormonal replacement therapy/oral contraceptives, exposure to ionising radiation at an early age (especially <30 years) and a high breast density can all contribute to breast cancer [1-3]. Here, BRCA1 is linked to breast cancer.