| Clinical | Demographic |
| Tumour characteristics | Age |
| Treatment therapy | Region |
| Comorbidity | Hospital of diagnosis |
| Medication history and use |
ERα, oestrogen receptor alpha; ERβ, oestrogen receptor beta; 17β-hydroxysteroid dehydrogenase 1 and 2; ProBe CaRe, Predictors of Breast Cancer Recurrence.