Is oestrogen receptor-negative/progesterone receptor-positive (ER−/PR+) a real pathological entity?

The existence of oestrogen receptor-negative (ER-)/progesterone receptor-positive (PR+) breast cancer continues to be an area of controversy amongst oncologists and pathologists.To re-evaluate breast cancers originally classified as ER-/PR+ via Oncotype DX® assay and compare molecular phenotype with Recurrence Score® (RS) result, clinicopathologic features and clinical outcomes were retrospectively obtained from electronic health records between...