ESR1 and neoplasm: During the analysis, the conforming variables were the pathological characteristics [for pN0 cases Tumour size, grade, PNI, LVI, ER (%), PR (%), PR group, Ki-67 (%), Ki-67 group, stage, clinical risk, NPI, NPI risk group; for the pN1 cohort all characteristics of the pN0 cohort were analysed except clinical risk, and the number of positive nodes] and the target variable was the RS.