Low RPA1 was strongly associated with features characteristic of aggressive behaviour including larger size, high grade, cellular de-differentiation and pleomorphism, high mitotic index, high Ki67 index lympho-vascular invasion, lymph node positivity, high-risk Nottingham Prognostic Index (NPI), and with ER negative, PR negative, and triple negative (TNBC) and luminal B breast cancer subtypes (all P values <0.001) (Supplementary Table 5). This evidence concerns the gene MKI67 and breast cancer.