MKI67 and neoplasm: A high nuclear CDK2/low nuclear CDK6 co-expression showed a significant association with a younger patient age (p = 0.035), high tumour grade (p < 0.0001), low tubule formation (p = 0.015), high degree of nuclear pleomorphism (p < 0.0001) and high mitosis (p < 0.0001), NST tumour type (p < 0.0001), presence of lympho-vascular invasion (p = 0.01), luminal B subtype (p < 0.0001), poor NPI groups (p < 0.0001), and high Ki67 expression (p < 0.0001) (Supplementary Table S7).