ESR1 and breast cancer: Although the panel was divided regarding the determination of the Ki-67 threshold that would justify chemotherapy in node-negative, hormonal-positive, and HER2-negative breast cancer as 35% of them decided that the threshold is not known, while only 47% set a threshold level of at least 30% to be the cutoff (Fig. 1), they mostly agreed that in ER-positive, HER2-negative, and T1-2 and N0-1 tumors, a Ki-67 ≤5% would not warrant chemotherapy, while a ki67 ≥30% would justify it (84%).