ESR1 and neoplasm: When comparing the characteristics of the study patients from our model to those of PREDICT, our patients were younger (age < 50 years, 50% vs. 23%) and had a larger size of tumor (size ≥ 3 cm, 47% vs. 20%), a greater number of positive nodes (node > 4, 27% vs. 11%) and a lower proportion of them were ER-positive (61% vs. 83%).