ESR1 and ductal breast carcinoma in situ: We selected frozen invasive tumor samples (ductal carcinoma in situ [DCIS]/invasive ductal carcinoma [IDC]) from 5 untreated patients with TNBC that were negative for the ER, PR, and Her2 receptor levels (evaluated by immunohistochemistry) and Her2 amplification (evaluated by cytogenetic analysis) for bulk exome sequencing followed by MPT profiling using a microfluidics system (Tapestri, Mission Bio) (Table S1).