ESR1 and neoplasm: Gallen International Consensus Guidelines recognize that while the use of transcriptomic assays is preferable for patients with intermediate risk, integration of traditional clinical factors (tumor grade, ER, PR, and HER2 status, and proliferation by Ki-67 assessment) can also be used to identify patients at low risk of recurrence to inform adjuvant chemotherapy treatment decisions when the more accurate and standardized transcriptomic assays are not available50.