ESR1 and breast carcinoma: Patients classified as ‘equivocal cases’ by classical clinical pathologic features (like women with ER+, HER2neg, N0, grade 2, Ki67 between 10–20%), and the integrating multi signatures (eg. EndoPredict, Genomic Grade Index, PAM50, Breast Cancer Index, Oncotype, DX, MammaPrint) for this reason can be used to help decision-making on treatment.