By multivariate analysis including grading, tumour size and ER immunohistochemical (IHC) status, the decision tree classification was shown to be the only significant independent predictor of DFS (P=0.0065), whereas histological grading (P=0.060), ER status (P=0.107) and tumour size (P=0.235) lost their significance (data not shown). The gene discussed is ESR1; the disease is neoplasm.