ESR1 and neoplasm: In the pT1a-pT1b tumours a lower incidence of prognostic biological factors associated with poor prognosis was observed: ER-negative status (12.7% vs 18.5%; p = 0.01), ER and PgR negative status (11.9% vs 17.9%; p = 0.01), and HER2-positive status (12.2% vs 18.7%; p = 0.006).