ESR1 and breast cancer: The proportion of TMB-H was significantly higher in specimens taken from metastatic sites and in those aged ≥ 50 (Fig. 3c, d).When the IDC and ILC groups were compared by subtype, 140 (11.2%) and 24 (20.3%) patients had ER+/HER2− breast cancer, respectively, with the latter group showing a significantly higher number of cases; however, for the other subtypes, no statistically significant difference was observed (Table 3).