ERBB2 and breast cancer: In the NRG/NSABP B-31 trial, where early HER2+ BC patients were randomized to receive either chemotherapy alone or in combination with trastuzumab, strTIL levels were reported to be positively associated with improved DFS in both trastuzumab-treated and trastuzumab-untreated patients, while no association between TIL levels and trastuzumab benefit was found [33].