ESR1 and neoplasm: These tools included: (1) the PREDICT tool, an online calculator (available at https://breast.predict.nhs.uk/) [41]; (2) the simplified risk score, which uses ER, PR, tumor size, nuclear grade and histologic grade to calculate a score ranging from 0–21; (3) the Tennessee prognosticator, which is based on age, tumor size and grade, PR status, presence of lymphovascular invasion, and histologic subtype; and (4) GR-PR, derived from the study group themselves, which attributes a score of 0–2 based on the presence of a grade 3 tumor or PR staining of any intensity in ≤20% of tumor cells.