Within the post-mortem tissue donation programs, UPTIDER (Belgium) and Hope for Others (USA), we first aimed to explore intra-patient heterogeneity of key prognostic and predictive markers (stromal tumor-infiltrating lymphocytes (sTIL), estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) and KI67). Here, ESR1 is linked to neoplasm.