ESR1 and neoplasm: Multivariate survival analysis including E2F1, nodal status, grade, tumor size, age, ER and ERBB2 status, and treatments revealed that only E2F1 and nodal status retained independent prognostic value in the STB data set (Table 4), and that E2F1, nodal status, tumor size, age and chemotherapy were significant in the NKI data set (Table 5).