MKI67 and breast cancer: The approach of individually matched case–control design shows that by elaborating conventional prognostic factors – Ki-67 proliferation index, p53 proto-oncogene expression, oestrogen hormone receptor and Her-2/neu proto-oncogene amplification detected by in situ hybridisation – with quantitative and statistical methods it is possible to intensify the prognostication of T1N0M0 breast cancer.