ESR1 and lung adenocarcinoma: We have demonstrated that nuclear ERα expression is an independent predictor of increased risk of recurrence in patients with pT1aN0 (≤2.0 cm) lung adenocarcinoma, especially in male patients, and positively correlates with poor prognostic immune microenvironments (CD3+ and FoxP3+ lymphocyte infiltration, and tumoral IL-7R expression).