ESR1 and neoplasm: When we focused on patients treated with chemotherapy, we observed a highly significant reduction of relapse-free survival independent from the tumor subtype (p < 0.01, HR 1.91) in ER− patients (p < 0.01, HR 2.97) and in ER−/PR− patients (p < 0.01, HR 3.08) among patients expressing high levels of ST3GAL2 (Fig. 7b).